HAYFEVER STUDIES 
in 
NEW HAMPSHIRE 
1947 STATE OF NEW HAMPSHIRE 
HAYFEVER STUDIES 
IN 
NEW HAMPSHIRE 
1947 
by 
Frederick J. Vintinner 
and 
George W. Morrill, Jr. 
State Department of Health 
John Samuel Wheeler, M. D. 
State Health Officer 
Division of Industrial Hygiene 
Frederick J. Vintinner, Director 
Concord, New Hampshire 
1948 “Measuring the Amount of Hayfever Pollen in the Air” INTRODUCTION 
Hayfever 
Playfever (pollinosis) consists essentially in hypersensitivity 
to the airborne pollens of weeds, grasses, shrubs and trees. The 
terms “hayfever” and “hay asthma” are misleading, since the 
manifestations are elicited not by hay itself, but by the pollens of 
various plants. The expression is further misleading since it is 
rarely that a patient has an actual fever, although it is not uncom- 
mon for the patient to complain of the sensation of feverishness. 
Other terms have been used rather loosely for this disease such 
as June cold. Summer catarrh and Autumnal catarrh. The ex- 
pression “hayfever” has been commonly used by physicians and 
laymen for such a long time that it is now generally accepted. 
The majority of hayfever cases are attributable to the pollens 
of weeds, grasses, shrubs and trees which are wind pollinated. 
Generally the showy flowered plants which are insect pollinated 
are not a factor in hayfever. One of the characteristics of hayfever 
is the fact that the patient is affected with the same symptoms each 
year approximately on the same dates. For this reason hayfever 
in New Hampsire may be classified into the following types, 
according to the seasons of plant pollination or flowering. 
1. The spring type, begins the latter part of March or the 
first of April, and continues to about the first of June. The 
etiological agents responsible for this type of hayfever are the 
pollens of trees, the principal genera in New Hampshire being: 
Elm. Maple, Willow, Poplar. Birch. Oak, Beech, and Ash. 
2. The summer type, begins about June 1 and extends to 
about the middle of July. Summer hayfever is caused by the 
pollens of grasses, Plantain and Dock. The principal grasses 
are Red and Meadow Fescue, Meadow Foxtail. Sweet Vernal- 
grass, June Grass, Orchard Grass, Canada Bluegrass, Timothy, 
and Redtop. 
3. The fall type, begins about the middle of August and 
continues until the end of the growing season. The pollen of 
Common or Short Ragweed (Ambrosia elatior) is the principal 
cause. The Tall or Giant Ragweed (Ambrosia trifida), Solidagos, 
Cocklebur, and Marshelder occur to such a small extent in New 
Hampshire as to be negligible. 
Symptoms 
The disease usually begins with repeated attacks of nasal 
irritation and sneezing and is sometimes accompanied by con- 
junctivitis and bronchitis. The symptoms appear at the start 
of the blooming season of the plant involved. The onset of 
symptoms varies with the individual, in some the manifestations 
are slow and gradual, while in others they are sudden and acute. 
5 The symptoms vary considerably in severity and duration, and 
may occur with great variation from hour to hour, or from day 
to day. 
Symptoms consist of an itching and sandy sensation of the 
eyelids, with redness, tickling, burning and itching sensations of 
the nose. Violent attacks of sneezing may occur, usually accom- 
panied by a clear thin mucous discharge. The mucous membrane 
of the nose is congested, and when irritation is severe, may 
cause a complete obstruction to nasal breathing. The ears, roof 
of the mouth, and throat often-times itch. In addition to these 
principal symptoms of hayfever, i. e. associated with the eyes and 
nose, there are severe clinical manifestations that occur rarely in 
certain individuals. 
Seasonal hayfever may affect some individuals throughout all 
three periods. It is estimated that over 50% of the hayfever 
patients are sensitive to more than one allergen. An estimated 
33% of those with summer type hayfever are also sensitive to the 
pollen of Ragweed. It is not uncommon for seasonal hayfever 
to begin in the spring and continue until the end of the growing 
season. Occasionally typical seasonal hayfever continues on into 
the winter, ceasing only with the cold weather. Hayfever may 
lead to secondary infection of the sinuses, and repeated attacks 
may develop eventually into asthma and bronchiectasis. 
Treatment 
Seasonal hayfever may be treated by having the patient leave 
the area in which the pollen occurs during the period when it is 
present. Spring or summer type hayfever is difficult to get away 
from unless one is upon the ocean, or in the mountains. Sufferers 
with the autumn type hayfever may avoid the attack by travelling 
into some of the pollen free areas. Pollen free air also may be 
obtained by air conditioning a room (removing pollens by filtration) 
by any one of the several methods available commercially.1 
Drug therapy has been used as a temporary expedient to modify 
the attack. The use of some of these drugs is dangerous and 
should be administered only under the supervision of a physician. 
The treatment of hayfever with pollen extracts has been advo- 
cated by some physicians. This usually is done after determining 
the sensitivity of the individual to various pollens or their extracts. 
Treatment usually is started several months prior to the pollinating 
time of the particular offending plants, and continued to the 
beginning of, or through, the entire season. 
PATHOGENESIS 
Hayfever is a disease of civilization. It has been estimated 
by some authors 2 that there are between 4,000.000 and 5,000.000 
hayfever patients in the United States. In other words, 3% of 
the entire population suffer with hayfever. Other authors arrive 
1 R. L. Cecil, M. D., Textbook of Medicine—5th edition. 
* Piness, G. and Miller. H.. J. A. M. A. 85 :339—1925 at even higher figures such as 8% (Pipes’) and 10% (Service4). 
Scheppegrell " estimated in 1022 that there were 1,200,000 hayfever 
sufferers. It is believed by some authorities that the incidence of 
hayfever in the United States is increasing continually. 
Several theories have been advanced to explain this continual 
increase, namely: 
1. More accurate and prompt diagnosis bv physicians. 
2. Continual irritation of the mucous membranes by smoke, 
gases and fumes from factories, chimneys, automobile 
exhausts, and by atmospheric dusts from heavy traffic. 
3. Tension and emotional strain of urban life. 
4. Exposure to massive concentrations of pollen through 
travel by means of automobiles and trains. 
Whatever the cause of this increase in hayfever may be. the 
fact remains that the disease causes a substantial amount of mor- 
bidity among the people. Such morbidity also causes great 
economic losses to the nation through medical expenses, absentee- 
ism from work, and a consequent decrease in industrial production. 
It is well known that people will travel long distances, often 
at great inconvenience and expense, to seek relief from this 
disease. One of the classic examples is that of Daniel Webster 
who. while Secretary of State, spent the greater part of the 
hayfever season in New Hampshire and Massachusetts away 
from his Washington desk, in search of relief. There is some 
evidence which suggests that he refused to be a candidate for 
the Presidency because of his incapacity during the hayfever 
season. It is known through his letters that he suffered severely 
from this disease, which he often termed autumnal catarrh and 
hayfever. 
Summary of Present Knowledge on the cause of Hayfever (Pollin 
osis) 
Present knowledge of the causes of hayfever may lie summar- 
ized as follows: 
1. Hayfever consists essentially in hypersensitivity of the in- 
dividual to the pollens of weeds, grasses, shrubs, and trees. 
2. In order for a susceptible person to contract hayfever, he 
must be exposed to sufficient concentrations of the pollen 
to which he is sensitive. The disease most commonly has 
its onset between the ages of 16 and 35 years, although 
it may appear in infants and in older people. 
3. There appears to be a relationship between the concentra- 
tion of pollen in the air to which patients are exposed, 
and the onset, severity and duration of the disease. 
4. The concentration of pollen in air is influenced by the 
3 Pipes, D. M.. South M. J. 30:1012—1937 
4 Service. W. C.. J. A. M. A. 112: 2034—1939 
6 Scheppegrell, W., Hayfever and Asthma. Philadelphia : December 1922 pollinating capacity and density of growth of the hayfever 
plants. These characteristics are affected by such eco- 
logical factors as altitude, topography, soil, precipitation, 
temperature, sunshine hours, cultivation, and other vege- 
tation. Thommen" figured that a single Giant Ragweed 
plant yields 8,000,000,000 pollen grains in five hours of 
active pollination. 
5. The symptoms appear chiefy during the pollination periods 
of the offending plants. They can, however, be induced at 
any time by exposing the patient to sufficient quantities 
of pollen. 
6. Individuals may be susceptible to more than one type of 
pollen. 
7. It has been estimated that 90% of hayfever is due to 
the pollen of Ragweed. 
8. The chemical component of the pollens which causes an 
allergenic reaction is not definitely known, evidence sug- 
gests it is a protein. According to Abramson,' the ex- 
citants of the symptoms of pollinosis are comparatively 
small molecules having properties similar to. but not char- 
acteristic of, proteins. The allergenic factor is not found 
on the outer shell of the pollen grain, but is somewhere 
inside the shell. 
Purpose of Study 
The study was undertaken by this Department to determine ex- 
isting conditions in the State relative to the occurrence and extent of 
growth of plants which caiise hayfever, and the resulting density 
of pollen in the atmosphere. The study also included the collection 
and analysis of data on soil types, vegetational types, topography, 
climactic conditions and other factual data affecting the growth of 
hayfever plants. The Department believed that the results of such 
a study would provide for an evaluation of the potential causation 
of the disease in New Hampshire, and serve as a basis for pre- 
ventive measures if they are considered necessary. 
A large number of inquiries are received yearly from hay- 
fever sufferers requesting information as to locations in the State 
which are free from hayfever pollens. There was no source from 
which this information could be obtained. Previous replies were 
based upon knowledge of locations recognized as being beneficial to 
hayfever victims due to a trial and error method of exposure. 
In the treatment of hayfever patients, physicians often are 
confronted with the problem of the type of allergens causing the 
disease. Basic facts must he known to make this determination. 
Among these are the species of plants which occur in the patients 
environment, and the types which produce pollen causing the 
disease manifestations. Such data could only be obtained by the 
0 Thommen: A. A. Hayfever 
7 Abranson: Annals of Allergy—January—February 1947, 
8 physician’s own observations and experience. It is planned that 
through the data obtained from this study, physicians in New 
Hampshire will he provided with pollination charts which will 
aid them in their diagnosis. While a few commercial drug esta- 
blishments have prepared and distributed such charts, it is ques- 
tionable if the data presented is based upon scientific studies. 
New Hampshire is well known as a recreational State because 
of the excellent natural features which exist within her boundaries. 
'The State also has a reputation among hayfever patients as a 
place where relief from their symptoms may be obtained. Various 
towns have inaugurated programs for the control of hayfever plants. 
Some of these programs are based upon scientific knowledge, others 
are not. 
There has been no cumulative source of information on the 
morbidity caused by hayfever. Tt is well known that such mor- 
bidity can cause much discomfort and illness, as well as absentee- 
ism and loss of production efficiency among industrial groups. It 
is the intent of this study to determine basic information on 
these subjects, and to evaluate existing conditions upon the data 
obtained. 
It is recognized that the degree of growth of hayfever plants 
and resulting concentration of atmospheric pollen are influenced by 
many factors from year to year. Data based upon one year’s 
study do not provide sufficient evidence to draw definite conclus- 
ions. However, it is our belief that the results here presented are 
fairly representative and with continual study, as planned, a more 
accurate evaluation will be made in the future. 
Air sampling devices used in this study are those recommend- 
ed by the National Pollen Survey Committee of the American 
Academy of Allergy. The final determination of airborne pollen 
density permits only the exact evaluation of the air at the sampling 
device, and will not provide data on pollen density at other loca- 
tions. Pollen density figures given in this report are representa- 
tive of conditions in the general atmosphere as measured at the 
sampling point. 
Tt is obvious that airborne pollen concentrations vary with 
the density of plant growth. Susceptible persons may develop 
symptoms when exposed to high concentrations from Ragweed 
growing near their dwellings, or when they travel through areas 
where Ragweed growth is heavy and at the pollinating stage. 
The data presented are useful in the evaluation of the concentra- 
tion of pollens carried by air movement or wind, and in the deter- 
mination of the magnitude of the hayfever problem. As will be 
noted in this report, the actual pollen densities at sampling loca- 
tions were generally low, which indicates that Ragweed growth 
is the individual problem of each community, since pollens are 
not of sufficient density to be carried into the community by the 
winds. Previous Studies 
Two surveys relating to hayfever have been made previously 
in New Hampshire. One was made in 1870 by Dr. M. Wyman, 
who found that the mountainous parts of northern New Hamp- 
shire were free of Ragweed. He concluded that the situation 
in the southern part of the State was probably similar to that of 
eastern Massachusetts. 
The second study was made in 1934 and 1935 at Bethlehem, 
in the White Mountains. These studies revealed only traces of 
Ragweed pollen in the air. 
Methods used in Studies 
It will be noted from the information and data presented in 
tliis report that the study did not get under way for the season 
of 1947 until June 22. The 1948 survey will he started not later 
than March 15th and will he ended October 15th. This will cover 
the entire growing season from early spring to late fall. 
The techniques, equipment, and methods of evaluating the 
density of airborne pollen were those recommended by the National 
Pollen Survey Committee of the American Academy of Allergy. 
Pollens were trapped on greased slides which were exposed in the 
“Durham Pollen Sampling Device” 
10 Durham sampling- device. This is the standard instrument for 
air sampling by the gravity slide method which was devised and 
calibrated by O. C. Durham, and approved by the National Pollen 
Survey Committee. 
The procedure briefly consisted of exposure of a one by three 
inch glass slide on the stage of a standard sampling device. Slides 
were exposed in the 12 selected locations each day from June 22, 
to October 15, inclusive. The slides were coated with a petrolatum 
jelly to which the pollen grains adhered as they were desposited by 
air movement. 
The sampling device consists of two 9 inch heavy, polished, 
stainless steel discs set horizontally three inches apart, and held 
with three struts. One inch above the center of the lower plane is 
a slide holder into which the slide fits readily. The supporting 
rod of the apparatus, thirty inches long, rises from a tripod base 
equipped with holes so that it may be screwed to a solid platform. 
Slides were received every two weeks at the Department Office 
in Concord for examination. A staining solution was added to 
the slides and a 22mm. square cover glass was placed approxi- 
mately in the center of the slide. The slides were placed under a 
compound binocular microscope, and the pollen grains counted and 
identified as to species. The counts were computed and reported 
on the basis of the number of pollen grains of each species found 
on a square centimeter of slide area. No attempt was made to 
supplement the one square centimeter figures with cubic yard 
estimates. Approximately 1600 slides were exposed and examined 
by this method. 
The slide counts were made by trained bacterologists and 
biologists. Pollens were provided by O. C. Durham of the 
Abbott Laboratories for use as standards for identification. Dr. 
Matthew Waltzer, Chairman of the National Pollen Committee, 
kindly ran check counts on several slides which were forwarded 
to him. These counts compared very favorably with those obtained 
by the Department personnel. 
11 “Identifying and Counting Pollen in the Laboratory" 
Supplementing- the actual measurement of the density of air- 
borne pollen, a reconnaissance type survey was made of the growth 
of Ragweed. Observers traveled throughout the State making 
observations. Maps and records were kept as to the growth, 
pollinating date, and general habitat of Ragweed. 
A questionnaire was included in the Department's monthly 
publication “Health News” requesting hayfever victims to for- 
ward to the Department certain information about their hayfever 
experience. Results of this questionnaire are discussed further in 
this report. Factors Influencing Growth of Hayfever Plants 
Following is a general description of the various natural fea- 
tures of New Hampshire which affect the growth of hayfever 
plants. The information is necessarily generalized due to the 
large land area covered. Detailed information concerning the area 
surrounding the various pollen collecting locations will be given 
in the discussion of the individual stations. 
The following tables are from the U. S. Weather Bureau re- 
cords for Concord, N. H. These records cover a period of at 
least 75 years and represent the various mean annual ranges. The 
information is representative for the entire State up to the medium 
altitudes, which would cover the major area of the State. All of 
the pollen collecting stations were well within this zone. 
Comparative Data—Concord, New Hampshire 
(Averages from all available records, including the year 1946) 
TEMPERATURE (°F) RELATIVE HUMIDITY 
(per cent) 
Mean 
Mean 
Mean 
1:30 
7:30 
1:30 
7:30 
Month 
Maximum 
Minimum Monthly 
AM 
AM 
PM 
PM 
Jan 
29.2 
•8.9 
19.0 
78 
79 
56 
70 
Feb 
31.0 
9.6 
20.3 
76 ' 
77 
54 
66 
Mar 
38.8 
20.0 
29.4 
76 
76 
52 
62 
Apr 
52.6 
30.7 
41.6 
77 
73 
46 
59 
May 
64.8 
40.9 
52.9 
85 
74 
49 
64 
J une 
73.5 
49.9 
61.7 
87 
77 
52 
67 
J uly 
79.0 
55.9 
67.4 
89 
80 
51 
70 
Aug 
76.4 
54.6 
65.5 
91 
84 
53 
73 
Sept 
69.1 
47.1 , 
58.0 
92 
86 
53 
77 
Oct 
58.6 
37.1 
47.8 
86 
85 
53 
73 
Nov 
44.5 
26.5 
35.5 
82 
82 
61 
73 
Dec,. 
32.9 
15.0 
24.0 
78 
80 
58 
71 
Annual 
Mean 
54.2 
33.0 
43.6 
83 
79 
53 
69 
Comparative Data—Concord, New Hampshire 
(Averages from all available records, including the year 1946) 
PRECIPITATION SUNSHINE WIND 
(inches) 
Snou’fall 
Number 
Percent 
Average 
(Unmelted) 
of 
of 
Hourly 
Prevail- 
Month 
Total Total 
Hours 
Possible Velocity 
ing Dir. 
Jan 
2.98 17.9 
139 
SO 
6.1 • 
NW 
Feb 
2.65 17.3 
154 
54 
6.5 
NW 
Mar 
3.11 11.6 
199 
57 
6.6 
NW 
Apr 
2.97 4.6 
205 
54 
6.9 
NW 
May 
3.12 0.1 
226 
53 
6.0 
NW 
June 
3.24 T 
268 
57 
5.2 
NW 
July 
3.69 0.0 
273 
57 
4.8 
NW 
Aug 
3.50 0.0 
261 
58 
4.6 
NW 
Sept 
3.47 T 
198 
55 
4.8 
NW 
Oct 
3.23 0.1 
163 
49 
5.3 
NW 
Nov 
3.27 5.3 
122 
44 
6.0 
NW 
Dec 
2.89 12.1 
112 
43 
5.9 
NW 
Annual 
38.12 69.0 
2323 
53 
5.7 
NW 
13 NUMBER OF DAYS 
Average 
Free ip- 
Snow, 
Clondi- 
itation 
0.01 
ness 
0.01 
inch 
(Scale 
Partly 
inch or 
or more 
Thunder- Fog 
Month 
0-10) Clear 
Cloudy 
Cloudy 
more 
(Melted) 
storms Dense 
J an 
5.5 11 
8 
12 
11 
8 
# 1 
Feb 
4.9 12 
7 
9 
9 
7 
0 1 
Mar 
4.8 13 
8 
10 
10 
5 
1 2 
Apr 
5.2 11 
9 
■ 10 
11 
3 
1 1 
May 
5.3 12 
9 
10 
10 
# 
3 3 
June 
4.8 12 
10 
8 
10 
0 
5 4 
July 
4.7 12 
12 
7 
10 
0 
6 7 
Aug 
4.7 13 
11 
7 
10 
0 
5 6 
Sept 
5.0 12 
9 
9 
10 
# 
2 9 
Oct 
5.3 12 
8 
11 
9 
# 
1 6 
Nov 
5.9 9 
8 
13 
10 
3 
# 3 
Dec 
5.9 10 
7 
14 
10 
6 
# 1 
Year 
5.2 139 
106 
120 
120 
32 
24 44 
The precipitation affecting the growth of plants during the 
normal growing season, is furnished primarily by thunder storms. 
These records for thunder storms would not cover Zone 1 and 
probably one-half of Zone 2. The wind velocities as reported in 
Concord would hold for the entire State, with the exception of 
the extreme north and along the seacoast, where they would be 
somewhat higher. The higher altitudes of the State are, with 
very few exceptions, those in which no major hayfever plants 
would occur. At these altitudes the land is heavily forested, pri- 
marily with the Spruce-Fir type, or is barren rock above timber- 
line. Therefore, these records generally would be indicative of 
growing conditions for hayfever plants. 
Comparison of the Weather Bureau records for 1947 with 
those of the mean annual records reveals the following: The 
month of April was normal for precipitation and temperature. 
The months of May and June had a precipitation slightly above 
normal, approximately 5%. together with a slight temperature de- 
ficiency. The temperature and precipitation for the month of 
July were slightly above normal. During the month of August 
the precipitation was about one third below normal, and the 
temperature somewhat above. The month of September had 
precipitation about 20 percent under the normal, and a temperature 
exceeding the mean annual. The month of October was consider- 
ably below the normal for precipitation, and had an excess of 
temperature. 
In the latter part of October and the first part of November, 
New Hampshire had such extreme forest lire weather that a 
state of emergency was declared. Huge fires raged in New Hamp- 
shire, Maine, and Massachusetts. 1 hose fires were a direct result 
of the deficiency in precipitation during the latter part of the 
growing season. 
14 The date of the average killing frosts, records extending 
from 1851 through 1947, were May 5th and October 3rd. The 
average growing season is 150 days. 
During the 1947 season the last killing frost in spring occur- 
ced May 15, and the first in the fall on September 27. This would 
indicate the 1947 growing season to he 135 days, which is 15 days 
below the average. 
The dates of the average growing seasons would not apply 
to most of the area in Zone 1, and that area in Zone 2 which 
lies above the medium altitudes. These figures would also be 
somewhat modified in the coastal area by the effects of the ocean. 
The growing season decreases from 10 to 20 days from the south 
to the north. 
The total annual precipitation increases from 38 inches in 
the southern part of the State to 44 inches in the extreme north. 
The normal summer rainfall increases from approximately 10 
inches in the south to 13 inches in the north, these figures are for 
the months of June, July and August. 
The altitude of New Hampshire varies from zero at the 
coast to 6,262 feet above the ocean at the top of Mt. Washington. 
These extremes offer a wide variation of weather, altitude, veg- 
etation, and soils. A comparatively small area of the State 
exceeds a moderate altitude of 4000 feet. 
The State, on the basis of vegetation and topography, can 
he divided roughly into 3 zones, which are: 
Zone 1 is that area which is north of the White Mountains 
proper, consisting primarily of Coos County. The topography 
is rolling, and the soil covered with a heavy stand of Spruce and 
Fir. The major industries are pulp and other forest industries, 
farming, and wholesale dairying. This country is also heavily 
endowed with areas in which the sportsmen and vacationists de- 
light. 
Zone 2 consists of the White Mountains and the National 
Forest contained in them. These mountains lie slightly above 
the center of the State in a more or less circular mass. The 
mountains range from moderately high to rugged peaks, and are 
dominated by the Presidential Range and Mt. Washington. The 
entire area is heavily forested, primarily with the Spruce-Fir type, 
with an admixture of hardwoods. Forest industries, and various 
tourist enterprises, predominate in this zone. 
Zone 3 consists of the central and southern sections of New 
Hampshire and ranges from hilly, to a low rolling disected plateau 
sloping gently from the White Mts. to the sea. There are occasional 
mountain peaks isolated in this general plains area which tapers 
off into the coastal lowland in the southeast. Vegetation in Zone 
3 ranges from pure stands of White Pine to pure stands of hard- 
15 “Zonal areas arbitrarily established on the Basis of Vegetation, 
Topography, Population, and Pollen occurrence” wood. This zone also contains most of the cities and manufactur- 
ing industries, together with dairying and poultry raising* 
Figure 2 shows New Hampshire’s general topography, divided 
into altitudinal regions increasing from light to dark shading. 
Most of the State’s soil cover consists of sandy or stony loam, 
which is excellent for forest growth and farm crops when cleared 
and when topography is not too severe. The river valleys provide 
sizeable areas of rich heavy soil. The U. S. Soil Survey classilies 
soil productivity as 60% non-arable. 29% poor, and 11% from 
fair to excellent. These figures would indicate that the area of 
New Hampshire suitable for farming is restricted. 
Reference is made to the attached forest timber type map 
(Figure 4) indicating generally the vegetational zones. The forests 
consist of approximately 50% softwood or conifers, and 50% 
hardwoods. The softwood acreage is approximately 29% White 
Pine and 21% Spruce and Fir. The hardwood acreage is made 
up of 27% Birch-Beech-Maple; 16% Oak; and 7% miscellaneous. 
The total forest area in New Hampshire is 4,671.693 acres. 
The total land area of New Hampshire, according to figures 
based on a survey of 1940,s can be broken down into the following: 
USE ACRES 
PERCENT 
Developed in Cities, Towns. 
Highways, etc. 334,983 
5.7 
Agriculture (less farm 
woodland) 723,199 
12.5 
Barren, permanently treeless 
bog, rock, sand, 45,485 
0.8 
Forest 4,671,693 
81.0 
Total 5,775,360 
100.0 
Froip the reconnaissance survey made by this Department it 
is estimated that less than 10% of the acreage listed for cities, 
agriculture, and barren would be that on which Ragweed, the 
main hayfever offender, could occur. Using these figures, less 
than 2% of the entire land area of New Hampshire is that on which 
Ragweed would be able to grow. 
Hayfever Plants 
The following hayfever plants occur in New England, accord- 
ing to Dr. R. P. Wodehouse in his book. “Hayfever Plants.” 
They are arranged in approximately the order of pollination by 
zones in New Hampshire. (See Figure 1). Their relative im- 
portance within the zones is indicated by use of letters, as follows: 
H-heavy; M-medium; L-light. 
s Biennial Report—N. H. Forestry and Recreation Comm.—1945-46 
17 TOPOGRAPHICAL MAP 
°f 
NEW HAMPSHIRE 
FROM UNITED STATES GEOLOGICAL SURVEY MAPS 
SHOWING CONTOUR. LINES AT VARIOUS 
ELEVATIONS ASOVE SEA'LEVEL, SHADING 
FROM LIGHT TO DARK AS ELEVATIONS INCREASE 
□ e a ■ 
0-200 200-500 500-1000 1,000-2000 AftOWB 200* 
NEW .HAMPSHIRE 
STATE PLANNING BOARD 
Figure #2—General Topography by Altitudinal Region Species 
Spring Season 
Summer Season 
Fall Season 
Winter Season 
Zone 
1 2 3 
Zone 
1 2 3 
Zone 
1 2 3 
Zone 
1 2 3 
Elms (Ulmus) 
L L H 
Maple (Acer) 
L L L 
Willow 
(Salix) 
L L L 
Poplar 
(Populus) 
L L L 
Birch (Betula; 
H H H 
Oak 
(Quercus) 
L L H 
Beech (Fagus) 
L L L 
Ash 
(Fraxinus) 
L L L 
Meadow 
Foxtail 
(Alopecurus 
pratensis) 
L L L 
Sweet Vernal 
Grass 
(Anthoxan 
thum odora 
turn) 
H M H 
English 
Plantain 
(Plantago 
lanceolata) 
L M K 
June Grass 
( Poa praten 
sis) 
H H H 
Orchard Grass 
(Dactylis 
glomerata) 
H H H 
Sorrel Dock 
(Rumex ace 
tosella) 
L L L 
Red Fesque 
(Festuca 
rubra) 
L L L 
Meadow 
Fesque 
(Festuca 
elatior) 
L L L 
Canada Blue 
Grass 
(Poa com- 
pressa) 
L L H 
Timothy 
(Phleum 
pratense) 
H L H 
Red Top 
(Agrostis 
alba) 
H L H 
Marshelder 
(Iva oraria) 
L L L 
Goldenrods 
(Solidago) 
L L L 
Short Rag- 
weed 
(Ambrosia 
elatior) 
M L 11 
Cockleburs 
(Xanthium) 
L L L 
“Table #2— Hayfever Plants in New Hampshire and Their Relative 
Zonal Importance” PODSOLS- 
FOREST SOILS 
PREDOMINANTLY 
1 STONY SOIL AREA 
KSSj SANDY 
LOAMS 
HEAVY SOILS 
DEVELOPED FROM 
C——1 ALUVIUM, SHALES, 
AND PHYLLITES 
“Figure #3—New Hampshire Soil Types Areas—U. S. Soil Survey” The most important of these species in New Hampshire are; 
Spring or tree season— Oak and Birch. Summer, or grass season— 
Sweet Vernalgrass, English Plantain, June Grass, Orchard Grass. 
Timothy, and Red Top. In the fall season, Ragweed is the most 
important species pollinating, and in fact Ragweed is the main 
offender in the State. Meadow Fescue. Meadow Foxtail, Lambs 
Quarters, Atemisias, Cocklebur, Tall Ragweed, and Marshelder 
occur so infrequently, or in such small stands, that they are not 
major causative agents of hayfever in this State. 
The pollination period for Elm, Maple, and Willow was over 
before the present study commenced. There were no pollen grains of 
these genera present on the exposed slides. Pollen grains of Poplar, 
Birch, Ash. June Grass. Orchard Grass, and Timothy, appeared 
on the slides June 22, the first day slides were exposed. Beech 
pollen appeared for the first time on June 26. Oak pollen first 
was found on the slides July 6. The first recorded date for Short 
Ragweed was August 15. Pollen of no other species listed by 
Wodehouse (Table $:2) were found on the slides. 
Location of Sampling Stations 
Pollen collection stations were located approximately 50 air 
miles apart. Reference is made to Figure 5 indicating station 
location and distribution. 
Stations were located wherever possible at places having per- 
sonnel on duty seven days a week. Through the cooperation of 
the State Fish and Game Department, personnel at four fish 
hatcheries changed the slides daily. Professor F. E. Hodge of 
Colby Junior College, while making daily weather observations, 
assisted in this study. Other stations were located at the homes 
or offices of various local health officers. Three of the stations 
were at the offices of personnel of the State Health Department. 
It was thought that representative sampling could be attained 
by spotting the stations as nearly the same distance apart as possible 
throughout the State. They were located from the Spruce-Fir 
forest type area in the North to the border of the State of Mass- 
achusetts ; and from the seacoast area on the East, to the Beech- 
Birch-Maple forest in the south-west. Vegetation, soil, altitude, 
and population were considered in the location of sampling station 
distribution. 
A further attempt was made to obtain a representative sample 
by placing the pollen collecting devices on different sites at the 
various stations. Some were on the roofs of the highest buildings 
in the largest cities, one on the crest of an open grassed area at 
an altitude of 1345 feet; some located in areas surrounded by farms, 
and others located in forested areas. Check slides were exposed 
in the City of Concord during the height of the Ragweed season in 
an attempt to determine any possible difference between having 
the pollen collecting device on the top of a high building, (State 
House Annex) and one located at the home of one of the Health 
Department employees. 
21 SPRUCE-FIR 
□ WHITE PINE 
NORTHERN 
i 1 HARDWOOD 
JIM H* 1*41 
“Figure #4—Forest Timber Type Map H. I. Baldwin—N. H. Forestry 
and Recreation Department” ti 1947 STATION LOCATIONS - 
• 1948 STATIONS TO BE ADDED 
JUNf 1436 Unlit* StpttmMr 1442 
“Figure #5—Location of Pollen Collection Devices” Results of Studies at Sampling Stations 
Each sampling station has been dealt with separately in re- 
spect to airborne pollen density, Ragweed growth, and other 
factors relating to the incidence of hayfever. The basis for the 
evaluation of Ragweed growth is discussed in detail under the 
section on reconnaissance surveys. 
STATION 1 was located about 2 miles east of the Town 
of Colebrook, in the Mohawk River Valley, at an altitude of 
1100 feet. The device was handled by the employees of the 
Colebrook Fish Hatchery, where the collecting device was placed. 
This hatchery is in a shallow valley, with a southern exposure. 
A Spruce-Fir forest surrounds the hatchery on three sides, the 
southern side being an old field of an abandoned farm. The station 
was partly protected from winds, but not to such an extent as to 
interfere with any pollen which might be carried through the 
general atmosphere. 
There was no Ragweed found within the immediate vicinity 
of the pollen collecting station. There was, however, a scattered 
and light growth of Ragweed in a few places in the Town of Cole- 
brook. 
The following graph indicates the density and frequency of 
airborne pollens at this site: 
RAGWEED 
OTHER HAYFEVER POLLENS 
ALL POLLENS 
‘Station #1—Daily Pollen Occurrence” 
24 Birch pollen occurred daily from June 23 to June 28 inclusive, 
the largest number showing on any one day being two grains per 
square centimeter. 
The pollen of Orchard Grass appeared on the slides for one 
day only on July 9. 
Timothy in relatively small numbers appeared on the slides 
on July 9, continuing to July 11. Timothy reappeared July 13 
and continued to July 16. 
From July 16, until the occurrence of Ragweed, September 
4, no pollens of the types generally considered as causing seasonal 
hayfever appeared on the slides. Grass pollen appeared only 
four days out of this period in amounts exceeding ten grains per 
square centimeter slide surface. 
The graph indicates that Ragweed pollen appeared on the 
slide September 4 for a count of three grains per square centimeter, 
and September 14, when only one grain was found per square 
centimeter. Ragweed hayfever, as indicated from these counts, 
is not a problem in the area surrounding this station. 
These data indicate that the area in and around Colebrook, 
excepting for one week out of the entire period studied is relatively 
free from airborne hayfever pollen. 
STATION 2 was located in the City of Berlin, on the roof 
of the highest building, at an elevation of 1110 feet. The station 
was maintained by employees of the State Health Department 
and the City Health Officer. 
The City of Berlin is located in the narrow valley of the 
Androscoggin River. The Presidential Range of the White Mts. 
lies as a barrier about 10 miles to the south. The river valley at 
Berlin runs directly north and south, and is protected on the west 
side by a low range of hills. Berlin is actually located at the 
hub of six valleys which radiate like the spokes of a wheel. The 
City is surrounded primarily by a Spruce-Fir forest which supplies 
wood for the Brown Paper Company. There are a few small farm 
scattered through the woods and valley bottoms. The station 
was exposed to the full sweep of the wind in all directions. 
Surveys for Ragweed revealed dense growths throughout mill 
yards, along the many railroad tracks, in vacant lots, and around 
residences. There was little Ragweed in the valley to the north, 
but heavy growths were noted in the City, and through the valley 
to the south. 
The following graph indicates the daily occurrence of airborne 
pollens at this location; 
25  RAGWEED 
OTHER HAYFEVER POLLENS 
ALL POLLENS 
“Station #2— Daily Pollen Occurrence” 
An examination of the graph of Station 2 indicates that the 
first day a slide was exposed, Birch pollen occurred in such abun- 
dance as to he an irritant to susceptible persons, with 22 grains per 
square centimeter being counted. Birch continued until June 26 
after which it was not again encountered on the slides. 
June grass occurred once, on July 7, when one grain was 
recorded. 
Timothy occurred once on the slides, July 9, when only three 
grains of pollen were seen. 
No other grass pollens were encountered at any time. 
Ragweed first occurred on August 23. when five grains were 
counted. Ragweed pollen continued to appear on the slide every 
day, except August 27 and 28. until September 10. One grain 
only was found September 15. The greatest concentration of Rag- 
weed found at one time was fourteen grains per square centimeter 
of slide surface. 
Counts at this station indicate that there were three days in 
which hayfever inducing pollens occurred in the general air to 
such an extent as to be conducive to symptoms of hayfever. These 
days were August 26, and September 1 and 2. Near the local areas 
26 in which Ragweed growths were heavy, the air would be more 
highly contaminated with pollen. 
STATION 3 was located in the Township of Carroll, about 
two miles north of the Village of Twin Mts., at an altitude of 
1340 feet. This station was maintained by the employees of a 
State Fish Hatchery, and was located in the center of the trout 
rearing area. The hatchery is located at the south end of the 
heavily forested Cherry Valley. The surrounding timber types 
are primarily Spruce-Fir. with a mixture of Poplar and Birch. 
There are a few scattered farms in the area. 
The presidential Range of the White Mts., lies about six miles 
to the south of this location. The collecting device was so located 
that it was exposed to the wind from all quarters, the only interfer- 
ence with air movement being a low hill about 500 yards to the 
south of the device. 
An examination of the surrounding area was made for 
Ragweed plants. Those growths found were scattered and few 
in number. Ragweed was classified as light even beside the 
main traveled road, and along the railroad right-of-way in such 
locations as are generally heavily infested. 
The following graph indicates the occurrence and densities of 
the various pollens. 
RAGWEED 
— OTHER HAYFEVER POLLENS 
ALL POLLENS 
“Station #3—Daily Pollen Occurrence” 
2 7 Examination of the data for Station 3 indicates that Birch 
pollen occurred from June 22 to June 24. inclusive. There were 
only two grains showing on the 22nd, and one grain apiece on the 
other two days. The pollen of Birch in this area is evidently not 
occurring in sufficient quantities to be detrimental. 
In the grasses, the pollen of Orchard Grass occurred June 23 
and 24. These were the only two days throughout the season in 
which any of the grass pollens appeared on the slides. The great- 
est number occurred on June 23 when five grains were counted. 
The airborne pollen of grass does not seem to occur in sufficient 
quantities to constitute a hazard. 
Ragweed pollen appeared on the slides August 30 and 31. 
No Ragweed pollen was found at any other time during the period 
of slide exposure. The highest count was August 31, when three 
grains were recorded. 
This station from June 25 until August 29 inclusive, had no 
pollens occurring which would be conducive to causing hayfever. 
At the time in which the pollens did occur, they occurred in such 
densities as to be considered negligible as far as seasonal hayfever 
is concerned. 
STATION ft: 4 was located in the center of the Township of 
Conway, at an altitude of 520 feet. The collecting device was 
in the yard of the local health officer and was supervised by him 
throughout the season. 
North Conway is in the Saco River Valley about five miles 
south of the point at which Pinkham Notch and Crawford Notch 
come together, and eight miles below the White Mts. The Town 
is situated on the northern edge of a large glacial outwash plain, 
and is on generally level land. A National Forest partly surrounds 
the region, which is noted for its winter sports and summer vaca- 
tionists. Dominant timber types are Spruce-Fir on the heights, 
merging into White Pine, Pitch Pine, and Oak on the plains. 
There are a few farms which are primarily engaged in dairying. 
The pollen device was open to the wind from all directions, 
excepting the east, where it had a slight interference from the 
home of the health officer. The only other interference was a 
large Elm tree which stood near the device and shaded it to 
some extent. 
An ocular survey of the surrounding area indicated a small 
amount of Ragweed, occurring in a more or less scattered manner. 
There were no extensive growths occurring. The area to the 
north was almost completely free of the plant. The following 
graph indicates the occurrence of the various pollens during the 
season:  RAG W CEO 
OTHER HAYFEVER POLLENS 
ALL POLLENS 
Station #4—Daily Pollen Occurrence’ 
An examination of the graph and records indicates the follow- 
ing: 
Birch pollen appeared on the slide the first day it was exposed, 
June 22, and continued to June 24. Birch reoccurred. once on each 
of the following dates; June 28, June 30, and July 1. The greatest 
number of Birch pollen grains was counted June 28, at which time 
eight grains were recorded. 
The pollens of the various grasses causing summer hayfever 
did not appear on the slides at any time throughout the entire 
season. This probably is due to the heavily forested character of 
the surrounding territory. 
Ragweed occurred at this station for the first time August 
25, when two grains appeared. The only other time that Short 
Ragweed occurred was on September 3, when seven grains were 
counted on the slide. At no other times was Ragweed noted in 
this area. 
It would appear from the foregoing that the incidence of sum- 
mer and fall hayfever in this area should be very slight. Ragweed 
pollen occurred on only one day in amounts sufficient to cause 
hayfever symptoms. 
STATION # 5. This station was operated by employees 
of the Warren State Fish hatchery, which is at an elevation of 
700 feet. The hatchery is located in a wide valley of the White 
29 Mts., on the banks of the Baker River. The valley runs generall}' 
north and south at Warren with the main mountain ranges at 
the north and east. 
The surrounding area is heavily forested, primarily Spruce and 
Fir, with a heavy admixture of various hardwoods. Extensive stands 
of White Pine appear at the lower elevations. There are a few 
small farms in the valley, most of which are engaged in general 
farming. 
The following graph indicates the occurrence and density of 
the various hayfever pollens: 
RAGWEED 
OTHER HAYFEVER POLLENS 
ALL POLLENS 
“Station #S—Daily Pollen Occurrence” 
Examination of the records and graph of this station reveals 
that Birch occurred on June 22 and 23. On neither day did the 
count rise beyond live grains of pollen per square centimeter of 
30 slide area. This is below the number suggested that may cause 
hayfever in susceptible individuals. 
Ash pollen occurred the same two days, June 22 and June 23. 
The greatest density occurred on June 23 when seven grains were 
counted. 
These were the only two days throughout the season when the 
pollen of trees causing hayfever appeared on the slides. 
The only grass pollen occurring was Timothy, which contri- 
buted one grain the first day, and continued on to July 16, with 
only June 25 and July 2 as blank days. There was a lapse of 
three days and Timothy reoccurred on July 20 with one grain, and 
July 22 with one grain. This was the last occurrence of any grass 
during the study period. The days from July 1 to July 8, excepting 
July 2, were the only ones in which the Timothy pollen count 
exceeded ten. It varied from 23 grains on July 8 to 215 grains on 
July 4. In the five days from July 3 to July 7, inclusive, the count 
ran from 69 to 215. 
An investigator made inquiries at the fish hatchery and its 
surrounding territory as to the probable cause for this high count. 
It was found that a farmer carried on his haying operations, during 
this period, on a field approximately 200 yards from the pollen 
device. A high percentage of his crop was Timothy, therefore, it 
is postulated that the haying operation was responsible for this 
high count. 
There were no hayfever inducing pollens found on the slides 
from July 23 to September 11 inclusive. 
Ragweed occurred September 12, 15. 17. and 27. On only 
two days of the four in which Ragweed occurred did the grains 
reach a count of five. It would seem from these figures that 
Ragweed, at present, is not an important problem in this area. 
It can be concluded that the hayfever problem in this area 
is one which should cause no concern. The only time the counts 
were excessive were those days on which haying operations were 
being performed. These counts only occurred then due to the fact 
that the hay field was so near to the collecting device. 
STATION 6 was located on the outskirts of Lebanon, on 
the lawn of the town clerk’s residence at an altitude of 600 feet. 
Lebanon is in the wide, shallow valley of the Mascoma River 
about three miles from the Connecticut River Valley. General 
exposure is southwest, the Mascoma River flowing from east to 
west. 
The surrounding area has many large dairy farms, and is 
intensively cultivated. Timber types in the adjacent hills are 
predominately White Pine, with an intermixture of various hard- 
woods principally Beech, Birch, and Maple. 
The collection device was somewhat shielded on the north-east 
side by a small barn situated about 100 feet away. There are 
31 a great many Elm trees throughout the Town, one of which partly 
shaded the sampling device. 
The reconnaisance survey for Ragweed plants classified the 
growth for most of the surrounding territory as being from moder- 
ate to heavy. There were no plants immediately adjacent to the 
site of the collecting device. 
The following- graph shows the density and occurrence of 
pollen; 
RAGWEED 
OTHER HAYFEVER POLLENS 
ALL POLLENS 
“Station #6—Daily Pollen Occurrence” 
Examination of the records and graph from this collection 
station indicates the following: 
32 Three grains of Poplar pollen were found on the slide, in a 
one square centimeter count on June 23. Poplar pollen did not 
appear again on the slides. 
Birch pollen appear on June 23 and 27; and on July 1, 2, and 9. 
The highest count per square centimeter was June 23 when four 
grains were recorded. 
Beech pollen was found on one day, June 26, when one grain 
was recorded. Beech did not occur at any other time. 
The pollen of June Grass was recorded June 25 to June 28 
inclusive. These were the only four days in which June Grass 
did appear. The highest count was made June 27 when four grains 
of pollen was seen. 
Orchard Grass appeared on the slides June 29 and June 30, 
one grain each day. In July the pollen was recorded the 1,4, 7, 8, 
9, and 14. The greatest number occurred on July 8, when eight 
grains appeared. 
Timothy put in its appearance at this station for the first 
time July 10. The only other days on which it appeared were 
July 11, 17, 23, and 24. The greatest number of pollen grains 
recorded at any time was July 24 when four were found. 
Ragweed occurred once, on August 19, when one pollen 
grain was found. Ragweed was not found at this station at any 
other time. 
It appears from these data that the problem of hayfever in this 
locality is not a major one in respect to contamination of the gen- 
eral air with offending pollens. Heavy growth of Ragweed in certain 
areas would cause air contamination in the vicinity of these areas. 
STATION $7 was located at a State fish hatchery about one 
mile south of Laconia at an elevation of 580 feet. The collecting 
device was maintained by employees of the State Fish and Game 
Department. This hatchery is located about three miles from 
Lake Winnipesaukee on the south slopes of the lake basin. The 
exposure is generally north and slightly west. 
The surrounding timber type is predominately White Pine 
with a mixture of Birch and Poplar. The area immediately north 
and some to the west of the hatchery is used for farming. The 
collecting device was located in such a manner that there was 
no interference to the wind in any direction, and small possibil- 
ity of pollution from other sources. 
An examination of the surrounding area revealed a moderate 
density of Ragweed plants to the north, and a relatively heavy 
occurrence in the City of Laconia. 
The following graph indicates the daily densities of hayfever 
pollens at this location: 
33  RAGWEED 
OTHER HAYFEVER POLLENS 
ALL POLLENS 
“Station #7—Daily Pollen Occurrence’ 
Examination of the records and graph for this station reveals 
the following facts: 
The pollen of Birch was found on the slide the hrst day it 
was exposed, June 22, and continued to June 24. Birch pollen 
was also recorded June 26, ,30, and July 1. The highest count 
occurred on June 22, when thirteen grains were recorded. The 
pollen did not exceed three grains per square centimeter on the 
other five days in which Birch was found. 
The pollen of Beech was seen on one day. June 27, when two 
grains were recorded. 
There were no other tree pollens, generally considered as 
hayfever inducing, found during the period these slides were 
exposed. 
34 June Grass occurred June 22. the first day the slides were 
exposed, and continued up to and including the 28th. These were 
the only days in which June Grass appeared. The highest count 
was made June 26. when eighteen grains were recorded. 
Orchard Grass occurred June 22, the first day a slide was 
exposed, and on June 23. There was a lapse of two days, then 
it reoccurred on June 26 and continued until July 13. It was last 
recorded as appearing on July 16. There were nine days in which 
Orchard Grass occurred in densities of more than ten. These were 
June 22, and 27; and July 1, 3, 6, 7, 8, 9, and 10. On July 7 
there were a total of 103 grains of pollen counted per square cen- 
timeter of slide area. This period was one in which the owners 
of the surrounding farms were doing their haying, causing the 
count to jump to this extreme figure. 
No other grass pollens were recorded as occurring on the slides 
exposed at this station. 
The pollen of Short Ragweed appeared here first on August 
26. There was a lapse of two days and reoccurrences were August 
29 and 31 ; and September 2, and 8. The highest count on 
any of these days was three grains of pollen per square centimeter 
of slide area. 
The data indicate that the seasonal hayfever sit.nation in 
spring and fall is not serious in respect to contamination of the 
general air. The summer hayfever pollens are present in sufficient 
quantities to cause some trouble to persons allergic to those parti- 
cular species. The modertae to heavy growths of Ragweed plants 
in certain areas at this location would cause an increase of the 
pollen density in the air surrounding these areas. 
STATION #8 was located at Colby Junior College in New 
London, at an altitude of 1345 feet. It was situated in the midst 
of a campus area, at the crest of a series of rolling hills, which drop 
off into the Connecticut Valley in the far distance. The only ob- 
struction to air movement was a school building about 100 yards 
south of the station site. 
There are some small farms in the area, none of which were 
close to the collecting site. The surrounding forest is primarily 
White Pine, with a mixture of Porch, Beech, Maple and Spruce-Fir 
types. 
A survey of the vegetation within a half mile of the campus 
was made for Ragweed plants. Those found were scattered and 
in very small concentrations. The entire area might be said to 
be generally free of Ragweed. 
The following graph shows the daily variation in airborne 
pollen densities in this area: 
35  RAGWEED 
OTHER HAYFEVER POLLENS 
ALL POLLENS 
‘Station #8—Daily Pollen Occurrence” 
Examination of the records and graph for this station indicates 
the following: 
Pollen from the Birches occurred on the slide the first day 
it was exposed. June 22 and repeated on June 23, 26, and 27. At 
no time did it exceed four grains per square centimeter of slide 
surface. 
Beech pollen occurred on only one day, June 26, when one 
grain was recorded. 
Orchard Grass appeared on the slides on June 25, 28, 29, and 
30; and July 1,4, 6, 7, 8, 10, 12, and 14. The counts did not exceed 
three grains per square centimeter of slide surface on any day. 
The only other pollen occurring on the slide was that of 
Timothy, which appeared one day only, July 15, when six grains 
per square centimeter were recorded. 
The pollen of Ragweed did not appear on the slides at any 
time during the course of the study. 
From the data as determined at this station, it would appear 
that this area is generally free from all hayfever inducing allergens 
considered in this study. 
36 STATION #9 was located at Concord on top of the State 
House Annex. This is one of the highest buildings in the City, 
and is situated approximately 340 feet above sea level. The station 
was maintained by the staff of the Division of Industrial Hygiene. 
The only major interference to the sweep of the wind at this 
station was that caused by the State House dome, which was 
approximately 200 yards north-east of the pollen device. 
Concord is located in the wide Merrimack River Valley, 
which runs north and south, and is bordered on both sides with 
low hills. The surrounding area is farmed to some extent, primar- 
ily for dairy and vegetable products. Predominating timber types 
are approximately 50% White Pine and 50% mixed hardwood. 
A survey of the surrounding area for Ragweed plants indicated 
moderate to heavy growths. These occurred on the street burms, 
in vacant lots, around the edges of peoples’ gardens, and in other 
waste areas. 
The following graph shows the daily density and character 
of pollen at this station: 
RAGWEED 
OTHER HAYFEVER POLLENS 
ALL POLLENS 
‘Station #9—Daily Pollen Occurrence” 
37 From the records and graph made of pollen concentrations 
at this station, the following can he educed: 
One pollen grain of Birch occurred on each of the following 
days, June 22, 26 and 30; and July 1 and 2. These were the only 
days in which Birch did occur. 
One grain each of Oak and Ash pollen was found on July 6. 
These were the only times at which any of the tree pollens 
under study occurred. 
The pollen of Orchard Grass occurred only on July 7, when 
two grains per square centimeter of slide area were recorded. 
Timothy pollen was found July 10. 13. and 24. The concen- 
tration did not exceed two grains per square centimeter of slide 
area. 
The pollen of Short Ragweed occurred from August 25 to 31 
inclusive; and September 1, 2, 3, 7, 8, 9, 12 and 16. Counts exceeded 
five per square centimeter on three of these days, the highest being 
August 29, when 26 grains were recorded. 
These data indicate that the hayfever pollen density in the 
general air was excessive in this area on three days. 
The air surrounding those areas in which Ragweed growths 
were classified as moderate and heavy would be more highly con- 
taminated with Ragweed pollen, and these areas would contribute 
to the pollen density which was determined in the general air. 
STATION #10 was located in Keene, on top of one of 
the highest buildings, at an altitude of 480 feet. It was maintained 
by Mr. Evan White, City Health Officer. 
Keene is situated at the northern edge of a large flat valley, 
immediately south of the foot hills of a low mountain range. The 
Ashuelot River runs through the City to the Connecticut Valley 
a short distance to the west. The territory surrounding Keene, 
excepting to the north and east, is heavily farmed. The northern 
and eastern regions are heavily forested, being predominantly White 
Pine and mixed hardwood. 
The collecting device was located so that there was no inter- 
ference to air movement, general exposure of the station being 
south-west. 
Examination of the vegetation within a mile of the station 
for Ragweed plants revealed moderate to heavy concentrations. 
These grew on the edges of roads, in vacant lots and in the perimeter 
of peoples’ gardens. 
The following graph shows the occurrence and density of 
hayfever pollens at this station: 
38  RAGWEED 
OTHER HAYFEVER POLLENS 
ALL POLLENS 
“Station #10—Daily Pollen Occurrence’ 
From the records and the graph the following facts can be 
educed; 
Tree pollen occurred only one day June 22, when four grains 
of Birch were recorded. 
Timothy first appeared July 4, and continued up to and in- 
cluding July 14, with the exception of the 10th. The count did 
not exceed eight grains per square centimeter of slide area on 
any day. This is the only time grass pollens were found on the 
slides. 
Ragweed pollen occurred August 26, 29. and 31 : and Septem- 
ber 1 through 5, 7, 11, 12, 16, 18, and 19. The count exceeded six 
grains per square centimeter on three days during this period; 
August 26, and September 3, and 4. The highest number for any 
day was eight on September 4. 
These data indicate that the Ragweed pollen density in the 
general air was excessive on three days. Persons exposed to the 
air in the vicinity of areas in which Ragweed growth was moderate 
to heavy would be subjected to higher concentrations of air borne 
pollen during the plant pollinating periods. 
STATION # 11 was located in Exeter at the home of one 
of the State Health Department employees, who maintained it 
throughout the survey. The only interference to the collecting- 
device was a house about 150 feet away, and a large Elm tree 
100 feet away. 
39 Exeter is located in the Southeast corner of New Hampshire 
at an elevation of 30 feet, approximately ten miles from the ocean. 
The surrounding area is moderately cultivated, primarily for dairy 
and truck farming. Forest types are predominately White Pine 
with an admixture of hardwoods. 
Examination of the area surrounding the station indicated a 
Ragweed density ranging from moderate to heavy, some plants 
being within 100 yards of the station location. 
The following graph indicates the density and occurrence of 
the various pollen being studied: 
RAGWEED 
OTHER HAYFEVER POLLENS 
ALL POLLENS 
“Station #11—Daily Pollen Occurrence” 
Examination of the records and graph for this location indi- 
cates the following facts: 
The only tree pollen occurring at this station was one grain 
of Birch on July 2. 
June Grass was recorded once during the course of the survey 
with one pollen grain per square centimeter of slide area July 1. 
The pollen of Timothy was recorded as occurring on July 12, 
13, and 18. On none of these days did the count exceed six grains 
per square centimeter of slide area. 
Short Ragweed appeared August 15, 25, and 27 through 31 ; 
and September 1, 3 through 15, 20 and 24. The counts exceeded 
six per square centimeter on only live of the twenty-two davs in 
which Ragweed was observed. 
40 Ragweed pollen density of the general air was excessive on 
5 days. The pollen density in the air in the vicinity of areas in 
which Ragweed growths were moderate to heavy would be higher 
and probably present over a longer period of time. 
STATION #12 was located in Nashua on the roof of the 
City Hall, at an altitude of 200 feet. This station was maintained 
by the staff of the local health officer. The building is one of the 
highest in the City, the only interference to air movement being 
a clock tower about 150 feet southwest of the collecting device. 
There were no other obstructions to interfere with operation of 
the device. 
Nashua is in south-central New Hampshire, about live miles 
north of the Massachusetts border. The City is located in a wide, 
shallow valley which has been eroded by the Merrimack River. 
There are no hills in any direction near enough to cause wind 
changes. 
The surrounding territory is moderately agricultural, primarily 
dairy and truck farms. The timber types immediately adjacent to 
the City are predominately scrub Oak, interspersed with some Poplar 
and White Pine. 
A survey within a one mile radius of the station location for 
Ragweed plants indicated a moderate to heavy growth. These 
plants occurred along the edges of the city streets, vacant lots, 
gardens, and in waste areas throughout the City. 
The following graph indicates the density and occurrence of 
hayfever pollens in this location; 
RAGWEED 
OTHER HAYFEVER POLLENS 
ALL POLLENS 
Station #12—Daily Pollen Occurrence” 
41 From the records and graph of this station the following in- 
formation can be educed: 
The only tree pollen found at this station was Birch, which 
occurred June 22, and 24. On each of these days there was one 
grain of pollen per square centimeter of slide area recorded. 
The grasses are represented at this location July 10 when one 
grain of June Grass pollen was recorded. This is the only time 
in which the pollens of grasses causing summer hayfever were 
found. 
Short Ragweed pollen was observed the following dates: 
August 18, 19, 23, 24, 28, 29, and 30; and September 2, 3, 6, 7, 
and 9 through 13 inclusive. The greatest number of grains appeared 
September 6, when eleven grains were recorded per square centi- 
meter of slide area. There were no other days when this figure 
was approached by half. From these data it appears that the 
pollen density of the general air was excessive for one day. In the 
vicinity of those areas where Ragweed growths were moderate and 
heavy, the amount of pollen in the air would be substantially 
increased. 
Summary of Results of Sampling Stations: 
A comparison of the graphs from all stations indicates a peak 
in airborne pollen which is on the decline at the time slides were 
first exposed. These pollens were in all cases from those of the 
various trees, the principle species represented being Birch. Due 
to the fact that the slides were exposed at the end of the flowering 
season for trees, conclusions in regard to these genera are not signi- 
ficant. Plans for the 1948 survey are such that the complete tree 
pollinating- season will be covered. 
The only stations at which the pollens of trees occurred to 
such an extent that they would be a factor in hayfever were #2 
and #5. These amounts appeared on the slides only for the 
first three days of the survey, occurring in negligible amounts 
after that. There were a few grains of Oak, Beech and Poplar 
recorded. These last appeared at scattered locations in small 
numbers, and were not a factor in hayfever during the period of 
study. 
Records were made of all pollens seen, both known and un- 
known. The graphs indicate the incidence of all pollens to be the 
highest during the tree flowering period. The pollens, other than 
those listed as being hayfever inducing, consisted primarily of Pine. 
Spruce, and Fir. 
Tree pollens had generally disappeared by the 25th of June. 
Grass pollens began to appear on the slides about the 1st of 
July, and had generally disappeared by the 15th of this month. 
The stations at which grass pollens appeared in sufficient density 
as to be a factor in hayfever were 5, and #7. 
At two of these stations, ijt5 and #7, there was a tremendous 
peak in Timothy occurrence in the period from the 5th to the 10th 
of July. This was such an outstanding departure from the normal 
42 amount being counted, that an investigator spent some time 
checking the farmers in the surrounding areas. It was found at 
both stations that owners of adjacent land had harvested their hay 
crop at this time. Examination of the hay in the barn revealed 
that a high percentage was Timothy. It is believed that these hay- 
ing operations caused an abnormal amount of pollen to be in the air 
at this time, which was detected on the exposed slides. 
Records for the grass season indicate that there were varying 
densities of other grass pollens in the air. These pollens were re- 
corded as being unknown, no attempt being made to identify 
them by species, due to the time necessary for identification. 
The information available from the present survey indicates 
the summer hayfever situation in New Hampshire, at least in the 
localities studied, is not one to cause particular concern. The 
pollen does not seem to be airborne in sufficient numbers or density 
unless artificially disturbed by an operation such as haying. 
The grass pollen season was generally over at all stations by 
the 15th of July. 
From the 15th of July until the 15th of August there were 
no pollens in the atmosphere which are considered harmful to 
hayfever victims. This was true at all stations. 
The first appearance of Ragweed was at station #11 on August 
15. It appeared at other stations in the following order: Station 
12, August 18; Station 6, August 19; Station 2, August 23; Stations 
4 and 9, August 25; Stations 7 and 10, August 26; Station 3, August 
30; Station 1, September 4; Station 5, September 11. Station 8 
recorded no Ragweed pollen at any time during the entire season. 
There were only five stations at which Ragweed occurred in 
sufficient quantities in the general air to be a factor in hayfever, 
according to density concentrations suggested by the American 
Academy of Allergy. These stations, with the number of days 
exceeding the limits are : Station 2, four days; Station 9, three days; 
Station 10, three days; Station 11, five days; and Station 12 one 
day. 
A Ragweed survey of the area within one mile of Station #2 
at Berlin revealed a relatively large number of plants. A large 
pulp mill there has miles of railroad track, and acres of ground on 
which pulpwood is usually piled, which were heavily infested with 
Ragweed. In addition, vacant lots, sides of streets and the grounds 
around residences showed growths of Ragweed plants in varying 
density. The plants were not present in the forest land north 
of the City, and were present in light to heavy densities south of 
the City. The counts at this station were affected by this dense 
growth of Ragweed in the city and on the pulp mill grounds. 
The upper two-thirds of New Hampshire, that is from Station 
#7 (Laconia) north, except the City of Berlin, was relatively 
free of airborne Ragweed pollen. Results from these stations 
indicate that, even in areas where Ragweed did occur on the slides, 
it occurred in the general air in such small amounts and on so few 
days, that its effect on hayfever sufferers should be of short duration, 
43 excepting in a few restricted local areas. This would not, of course, 
be true for individuals living in the vicinity of places where 
Ragweed growth was moderate or heavy. 
Ragweed pollen, excepting at Stations 9, 10 and 11, had com- 
pletely disappeared from the slides by September 15. It continued 
at these three stations for about 10 days longer, but in small 
amounts. 
Reconnaissance Surveys; 
Supplementing the actual pollen count from exposed slides, a 
reconnaissance survey of the entire State was made. The purpose 
of this reconaissance survey was to determine the actual stand of 
Ragweed in the various areas of the State. 
“Short Ragweed Along the New Hampshire Seacoast’ 
The following1 method of recording the density of growth 
was used: 
Evaluation was based on observed growth along the highways, 
in vacant lots, cultivated fields, and various waste areas through- 
out the cities and towns. The density and extent of growth in 
listed areas was estimated, and classified into four categories, which 
are: negative, light, medium, and heavy. No attempt was made 
at actual measurement of the density of growth, results being 
based entirely upon visual estimates of three observers working 
independently. 
The density growth categories were arbitrarily established 
according to maximum growth as found in New Hampshire, and 
will not, of course, parallel results of other studies in states 
where hayfever plant growth is more extensive. 
44 No instances were found where areas of Ragweed exceeded 
more than one-tenth of an acre. The areas classified as heavy 
consisted essentially of a one to two foot width of Ragweed 
growth in the bnrm running continuously along the highways, and 
along town or city streets. Growths were also evaluated as found 
in cultivated areas, such as corn fields and bean patches, in vacant 
lots, near telephone poles, driveways, commercial buildings, filling 
stations and residences. Ragweed attained its heaviest growth in 
the center of the largest cities and towns. Many resorts and 
hotels in an otherwise Ragweed-free area had Ragweed growing 
immediately beside the buildings, and throughout the entire service 
area at the rear of the establishment. It was noted in many areas 
that Ragweed grew along the edges of main highways in strips 
averaging 1-2 feet in width. However when the sides of the high- 
way were shaded by trees, or heavy growths of grasses, shrubs 
and ferns, no Ragweed was seen. 
Following is a list of the Townships in New Hampshire, by 
Counties, according to the observed Ragweed growth: 
(Note; Density growth classification was arbitrarily establish- 
ed according to maximum growth as found in New Hampshire.) 
Following is a list of the Townships in New Hampshire, by Coun- 
ties. according to the observed Ragweed growth : 
Name 
Negative Light 
Medium 
Heavy 
Belknap County 
Alton 
X 
Barnstead 
X 
Belmont 
X 
Center Harbor 
X 
Gilford 
X 
Gilmanton 
X 
Laconia 
X 
Meredith 
X 
New Hampton 
X 
Sanbornton 
X 
Tilton 
X 
Carroll County 
Albany 
X 
Bartlett 
X 
Chatham 
X 
Conway 
X 
Eaton 
X 
Effingham 
X 
Hale’s Location 
X 
Hart’s Location 
X 
Jackson 
X 
Madison 
X 
Moultonborough 
X 
Ossipee 
X 
45 Name 
Negative 
Light 
Medium 
Heavy 
Sandwich 
X 
Tam worth 
X 
Tuftonboro 
X 
Wakefield 
X 
Wolfehoro 
X 
Cheshire County 
Alstead 
X 
Chesterfield 
X 
Dublin 
X 
Fitzwilliam 
X 
Gil sum 
X 
Harrisville 
X 
Hinsdale 
X 
Jaflfrey 
X 
Keene 
X 
Marlborough 
X 
Marlow 
X 
Nelson 
X 
Richmond 
X 
Rindge 
X 
Roxbury 
X 
Stoddard 
X 
Sullivan 
X 
Surry 
X 
Swanzey 
X 
Troy 
X 
Walpole 
X 
Westmoreland 
X 
Winchester 
X 
Coos County 
Atkinson and Gilmanton 
Academy Grant 
Bean’s Purchase 
X 
X 
Berlin 
X 
Cambridge 
X 
Carroll 
X 
Chandler’s Purchase 
X 
Clarksville 
X 
Colebrook 
X 
Columbia 
X 
Crawford’s Purchase 
X 
Dalton 
X 
Dartmouth College Grant 
X 
Dix’s Grant 
X 
Dixville 
X 
Dummer 
X 
Errol 
X 
Erving’s Location 
X 
46 Name 
Negative 
Light 
Medium 
Heavy 
Gorham 
X 
Green’s Grant 
X 
J efferson 
X 
•Kilkenny 
X 
Lancaster 
X 
Martin’s Location 
X 
Milan 
X 
Millsfield 
X 
Northumberland 
X 
Odell 
X 
Pinkham’s Grant 
X 
Pittsburg 
X 
Randolph 
X 
Sargents Purchase 
X 
Shelburne 
X 
Stark 
X 
Stewartstown 
X 
Stratford 
X 
Success 
X 
Thompson and Meserve’s 
Purchase 
X 
Wentworth’s Location 
X 
White tie Id 
X 
Grafton County 
Alexandria 
X 
Ashland 
X 
Bath 
X 
Benton 
X 
Bethlehem 
X 
Bridgewater 
X 
Bristol 
X 
Campton 
X 
Canaan 
X 
Dorchester 
X 
Easton 
X 
Ellsworth 
X 
Enfield 
X 
Franconia 
X 
Grafton 
X 
Groton 
X 
Hanover 
X 
Haverhill 
X 
Hebron 
X 
Holderness 
X 
Landafif 
X 
Lebanon 
X 
Lincoln 
X 
Lisbon 
X 
47 Name 
Negative 
Light 
Medium 
Heavy 
Littleton 
X 
Livermore 
X 
Lyman 
X 
Lyme 
X 
Monroe 
X 
Orange 
X 
Orford 
X 
Piermont 
X 
Plymouth 
X 
Rumney 
X 
Thornton 
X 
Warren 
X 
Waterville 
X 
• 
Wentworth 
X 
• 
Woodstock 
X 
Hillsborough County 
Amherst 
X 
Antrim 
X 
Bedford 
X 
Bennington 
X 
Brookline 
X 
Deering 
X 
Francestown 
X 
Goffstown 
X 
Greenfield 
X 
Greenville 
X 
Hancock 
X 
Hillsborough 
X 
Hollis 
X 
Hudson 
X 
Litchfield 
X 
Lyndeborough 
X 
Manchester 
X 
Mason 
X 
Merrimack 
X 
Milford 
X 
Mt. Vernon 
X 
Nashua 
X 
New Boston 
X 
New Ipswich 
X 
Kingston 
X 
Londonderry 
X 
New Castle 
X 
Newfields 
X 
Newington 
X 
Newmarket 
X 
Newton 
X 
North Hampton 
X 
48 Name Negative Light Medium Heavy 
North wood 
X 
Nottingham 
X 
Plaistow 
X 
Portsmouth 
X 
Raymond 
X 
Rye 
X 
Salem 
X 
San down 
X 
Seabrook 
X 
South Hampton 
X 
Stratham 
X 
Windham 
X 
Strafford County 
Barrington 
X 
Dover 
X 
Durham 
X 
Farmington 
X 
Lee 
X 
Mad bury 
X 
Middleton 
X 
Milton 
X 
New Durham 
X 
Rochester 
X 
Rollinsford 
X 
Somersworth 
X 
Strafford 
X 
Sullivan County 
Ac worth 
X 
Charlestown 
X 
Claremont 
X 
Cornish 
X 
Croydon 
X 
Goshen 
X 
Grantham 
X 
Langdon 
X 
Lempster 
X 
N ewport 
X 
Plainfield 
X 
Springfield 
X 
Sunapee 
X 
Unity 
X 
Washington 
X 
Pelham 
X 
Peterborough 
X 
Sharon 
X 
Temple 
X 
Weare 
X 
Wilton 
, - - x Name 
Negative Light 
Medium 
Heavy 
Windsor 
X 
Merrimack County 
Allenstown 
X 
Andover 
X 
Boscawen 
X 
Bow 
X 
Bradford 
X 
Canterbury 
X 
Chichester 
X 
Concord 
X 
Danbury 
X 
Dunbarton 
X 
Epsom 
X 
Franklin 
X 
Henniker 
X 
Hill 
X 
Hooksett 
X 
Hopkinton 
X 
Loudon 
X 
Newbury 
X 
New London 
X 
Northheld 
X 
Pembroke 
X 
Pittsfield 
X 
Salisbury 
• 
X 
Sutton 
X 
Warner 
X 
Webster 
X 
Wilmot 
X 
Rockingham County 
Atkinson 
X 
Auburn 
X 
Brentwood 
X 
Candia 
X 
Chester 
X 
Danville 
X 
Deerfield 
X 
Derry 
X 
East Kingston 
X 
Epping 
X 
Exeter 
X 
Fremont 
X 
Greenland 
X 
Hampstead 
X 
Hampton 
X 
Hampton Falls 
X 
Kensington 
X 
50 Attention is invited to photographs 4, 5, and 6 illustrating 
areas which were classified by the observers as being heavily in- 
fested with a growth of Short Ragweed. 
Area Surrounding the State: 
The hayfever incidence in New Hampshire is effected by the 
area surrounding the State to some extent, particularly in those 
regions immediately adjacent to the border. These surrounding 
areas effect the situation as follows: 
The north end of the State, and about twenty-five miles of 
the north-western part, borders on Canada. The land in Canada be- 
yond the Boundary Mountains is largely plains and heavily culti- 
vated. The area to the west is primarily forest land. Ragweed and 
grasses which may occur in these cultivated areas will have little 
or no effect on the populated sections of New Hampshire, due 
to large tracts of privately owned timber land which act as a 
barrier. The forested portion of Canada would have a very negli- 
gible effect as Spruce and Fir are the predominating timber types. 
The western neighbor is Vermont, whose boundary runs com- 
mon with New Hampshire along the Connecticut River, for more 
than nine-tenths of the entire western length of the State. The 
northern quarter of Vermont, adjacent to New Hampshire is largely 
timber land. This timber type is once again the predominating 
northland Spruce-Fir, with an admixture of hardwood, primarily 
Beech and Birch. Birch pollen may have some effect on the hayfever 
incidence in the northern reaches of the State. 
The lower three-quarters of Vermont is heavily farmed. These 
farms are in the rich river bottoms of the Connecticut River Valley, 
and are mostly given over to dairying. Hay crops are raised for 
cattle feed, and some of these plants are those which cause hayfever. 
There is also Ragweed, which varies in density from light to ex- 
tremely heavy. 
The prevailing winds in New Hampshire are from the north- 
west throughout all months of the year. Therefore, any hayfever 
plant pollens which are produced in Vermont, particularly in the 
Connecticut Valley Region, will probably find their way into New 
Hampshire. This is particularly important as the Valley on the 
New Hampshire side is as heavily populated as on the Vermont 
side, and it is possible for the Vermont allergens to have some 
effect on the people in these areas. 
Massachusetts borders New Hampshire on the south, but would 
have little effect on the hayfever situation in the State, due to the 
prevailing winds being from the northwest. The adjacent central 
and western parts of Massachusetts are made up of small farms 
and farm woodlots. Timber types in the farm woodlots occur in 
about the same proportion as they do in the southern part of New 
Hampshire. The eastern part of Massachusetts is heavily indus- 
trialized, and the cities are surrounded by truck gardening farms. 
Excepting for areas very close to the New Hampshire border, at 
51 “Short Ragweed Growth in the City of Concord” times when the winds were blowing- from the south or southeast, 
hayfever pollens as they occur in Massachusetts would have little 
effect on the problem in New Hampshire. 
Maine borders New Hampshire on the east entirely, excepting 
for an eighteen mile stretch of New Hampshire coast line, and a 
small area of the industrialized section of Massachusetts. The 
Maine country is heavily timbered for nearly its entire length. 
Timber types vary from Spruce-Fir in the north, to White Pine 
in the south. These two softwood timber types are interspersed 
with hardwoods consisting primarily of Birch, Beech, and Maple; 
with Oak appearing at the south. Due to the direction of the prevail- 
ing wind in New Hampshire, and the vegetational types along the 
border, the hayfever incidence should be little effected by pollens 
as they may occur in the State of Maine. 
Generally speaking, the only area adjacent to New Hampshire 
which would have an appreciable effect upon its hayfever problem, 
is that land which lays along the Connecticut Valley in the State 
of Vermont. 
Control Measures 
The data from these studies indicate that the pollen of Rag- 
weed is the primary cause of seasonal hayfever in New Hampshire. 
There are various methods of Ragweed control which may be 
used. These control methods include the following: 
(1) Pulling 
The simplest and least expensive method of control is pulling 
up the plants as they appear. This method is slow, and can be 
applied only to relatively small areas, where the density of growth 
is high. This method could be used primarily around residences, 
vacant lots, small resorts, and in the center of cities and towns, where 
the surrounding area was relatively free of Ragweed. 
(2) Cuttings 
Another method of control is by the use of various cutting 
instruments such as scythes and mowing machines. This can be 
used in somewhat larger areas, particularly by farmers and local 
groups who are interested. In order to carry out this system 
successfully, several cuttings a year have to be made. The cutter 
bar on a standard mowing machine can be raised to cut off the 
tops of the plants early in the season. This can be done in rough 
pasture lands, large city lots, and along the right-of-way of various 
town and city streets. The character of Ragweed is such, however, 
that if the top is not cut off immediaely prior to the beginning of 
the flowering season the plant will continue to develop flower 
heads, pollinate, and pollen will be released into the air. Examples 
of this were noted along some of the highways, where the plant 
had been cut back during the course of the State Highway Depart- 
ment’s regular weed control program. The plants flowered and 
pollinated when only three to six inches in height, which is partic- 
ularly striking when the normal height of this plant is two to three 
feet. 
53 (3) Herbicides 
The most efficient and inexpensive control method for use on 
large areas are herbicides. These may be placed in three major 
groups: 
A. Soil sterilants—These chemicals make the soil toxic to 
plants. They are used either in sprays or in dry form. Sodium 
chlorate, sodium arsenate, and borax are the principal compounds 
in this class. .Soil sterilants are chiefly used for fire lanes, parking- 
lots, railroad right-of-ways, and other places where vegetation is 
not wanted. 
H. Non-selective contact herbicides—These chemicals destroy 
top growth of plants when they are wetted with the spray. They 
do not kill roots or perennials. Contact herbicides are used in 
places where mowing is impractical, or where vegetation should 
he kept in check, such as ditch banks, fence rows and the edges ol 
lawns. 
C. Selective herbicides—These are chemicals which may be 
sprayed on an area to destroy the unwanted growth, while not 
affecting that growth which is desirable. 
“New Hampshire State Highway Department Spraying 
2, 4-D for the Control of Ragweed” 
There are three sub-groups of these selective herbicides: 
a. Those selective because they do not wet the crop; b. oil sprays 
that kill most plants; and c. the growth regulator or hormone 
type. The only one of these three groups which is practical for 
Ragweed control is the so called 2, 4-Dichlorophenoxyacetic Acid, 
(commonly known as 2, 4-D.) The effect of 2, 4-D is physiological 
in that the chemical, or its effect, travels through the plant system 
to induce a telemorphic response which contributes to the death of 
54 the plant. The action is not rapid and death comes on gradually 
but surely. 
The remarkable thing about 2, 4-D is that it affects most 
broad-leaved plants but usually not the grasses. It may be used 
as a selective spray for turf to kill Ragweed, Dandelions, Plaintain 
and many other weeds. Care should be used in handing this 
2, 4-D so that the chemical will not land on some of the more 
desirable broad-leaved plants, such as the various horticultural 
species used in landscaping. This chemical is non-toxic to man 
or animals. 
2, 4-D is produced by a number of manufacturers, and may be 
purchased in local stores. It is usually applied in a spray, using the 
proper concentration found on the container as given by the 
manufacturer of the product. 
Control Programs 
The New Hampshire State Highway Department, during the 
summer of 1947, conducted a program of Ragweed control along 
certain highways. This spraying was done principally around the 
Town of Lancaster, using a tank truck and 2, 4-D solution. 
Several communities have inaugurated control programs spon- 
sored by social organizations. These for the most part consisted of 
pulling Ragweed along the principal streets, in vacant lots and 
around residential homes. 
Control of Ragweed within the limits of various communities 
can be obtained through such programs of pulling or spraying. 
This activity should be supplemented in the less congested areas 
by local highway department equipment, with facilities for spray- 
ing 2, 4-D solution. Such programs are of particular interest to 
resort areas. 
It should be noted however, that the seeds of the Ragweed 
plant remain viable in the soil for a period of forty to fifty years. 
Control by hand methods necessarily disturbs the soil, thereby 
creating a place in which the plants will reoccur. These control 
methods must be continued over a period of years to reduce Rag- 
weed growh to an effective point. 
Questionnaire on Hayfever Experience 
A questionnaire was included in one issue of the Department’s 
monthly publication, “Health News,” requesting the recipients, 
if they were hayfever victims, to fill out the attached form and 
return it to the State Health Department. This questionnaire in- 
cluded spaces for the name and address of the individual, the 
date on which their symptoms of hayfever began for the current 
year, the period of years in which they had had the symptoms of hay- 
fever, and whether or not they had been treated for this disease. 
The circulation of this publication includes approximately 9,500 
residents. 
Answers to this questionnaire were received from eighty per- 
sons. While it is realized that data obtained through question- 
55 naires of this type is subject to many criticisms, an analysis of the 
data received showed the occurrence of hayfever among those in- 
dividuals who returned the questionnaires as follows; Spring Hay- 
fever 2.5% ; Summer Hayfever 12.5% ; and Fall Hayfever 82.5% ; 
the percentage affected in all three seasons was 2.5%. 
The largest percentage of the group is affected during the 
fall, or Ragweed, season. Eighty-two and one half percent of 
the affected people reported their symptoms occurring at this 
time. This is particularly striking due to the fact that Ragweed 
is listed by individuals in case after case as being the plant responsi- 
ble for this disease. 
The data from this group showed the geographical distribution 
of cases according to zones as follows: 
Zone 
Spring 
Summer 
Fall 
All-Seasons 
T otal 
1 
0 
1 
4 
0 
5 
2 
1 
4 
12 
0 
17 
1 
5 
50 
2 
58 
Total 
2 
10 
66 
2 
80 
The incidence of Hayfever in New Hampshire can not he 
determined or estimated from the data received from this question- 
naire. 
Summary 
The results of this preliminary study suggest that Ragweed 
hayfever in New Hampshire, when compared with other more 
intensively cultivated areas in the northeast is not serious, and read- 
ily lends itself to nearly complete control. This conclusion is sup- 
ported by the following facts: 
(1) A large percentage of the land area of the State is at 
such an altitiude that Ragweed will not grow. 
(2) Approximately 81% of the total acreage of the State is 
forest, in which Ragweed does not grow. 
(3) The various States and Provinces surrounding New 
Hampshire, with the exception of a small part of Vermont, have 
little or no effect on the airborne pollen density in this State. 
(4) Data on airborne pollen concentrations was obtained 
throughout the State, at twelve stations located fifty air miles apart. 
These data indicate that the airborne pollen concentration was not, 
in general, occurring in quantities sufficient to cause hayfever 
symptoms, except for five locations, and at these for only short 
periods of time. 
(5) A reconnaisance survey of the State made to evaluate 
Ragweed growths showed that, in most areas, growths were not 
of sufficient magnitude but that they could be controlled readily. 
Many localities were found to be practically free, or to have very 
light growths in restricted areas. In other areas the growth was 
found to be more extensive, but no Ragweed growths were found 
which exceeded one-tenth of an acre. It is estimated that Ragweed 
has a probable habitat of less than 2% of the State’s area. 
In respect to hayfever caused by pollens of trees, the data 
obtained in this study is insufficient to make any evaluation of the 
56 problem. It is expected that such data will be obtained in future 
studies. 
Hayfever caused from the pollens of grasses may be placed 
in a similar growth category with Ragweed hayfever. Factors 
such as the large forest acreage have a similar importance iu 
reducing the incidence to grass hayfever as to Ragweed hayfever. 
Haying operations will temporarily affect the pollen concentra- 
tions in air as described in this report. 
Ragweed pollen concentrations in the air at the twelve sampl- 
ing stations were very low, except at five stations for short periods 
of time. In general, the pollen density was greater in the southern 
part of the State. These data suggest that the exposure of indi- 
viduals to hayfever pollen is a local problem, namely that of in- 
dividual communities, and the hayfever patient's own immediate 
environment. In other words, the hayfever pollen concentrations 
are not sufficient to be transported into other communities by 
air movement, or wind, in sufficient quantities to be detrimental 
to hayfever victims. In addition, the general air in the communities 
studied was only slightly contaminated with pollens except as 
noted above. 
Reconnaisance surveys showed that the growth of Ragweed 
was high in areas of dense population and the growth decreased 
as the population decreased. Ragweed appears to be a civilized 
plant, occurring mostly in the waste areas surrounding human 
habitations, and is unable to compete with the hardier plants in 
the wild. This fact is well demonstrated by this study where it 
was found that the forested and mountainous two-thirds of the 
State is comparatively free of Ragweed. Heavily forested land, 
altitude, soil types and human concentrations all affect Ragweed 
growth. 
Returns from the hayfever questionnaire show that a few of 
the allergic individuals live in the same general locality where little 
or no pollen appeared on the sampling slides. Investigation re- 
vealed that these patients were living in dwellings where the yard, 
back of the garage, or surrounding waste area had small local 
growths of Ragweed. Many of these persons worked around 
their yards in close proximity to the Ragweed, and brushed re- 
peatedly against pollinating plants. Slight movements of the 
flowering plant will release thousands of pollen grains into the 
air in the immediate breathing zone of the individual. 
It should be noted that the collecting devices were operated 
in an attempt to evaluate the average pollen density being carried 
some distance by air currents, and will not measure specific local 
air concentrations. 
During the course of the survey investigators found many 
individuals who said they knew Ragweed on sight. Few recog- 
nized the plant when it was actually shown to them. Pigweed 
(Amaranthus) was commonly confused with Ragweed, and vice 
versa. Individuals ordinarily well-informed called practically any 
57 plant “Ragweed” which had some of the same growing habits and 
characteristics. Before any control program could be inaugurated, 
it would be necessary to inform the public as to what Ragweed 
is, where it grows, and what can be done to control it. Many 
resort hotels, cabins, and tourist homes in our large generally 
pollen free areas could afford their guests complete freedom from 
Ragweed pollen with a little Ragweed control in their own back- 
yard. 
This report covers the period from June 22 to October 15, 
1947. Additional study will be made in order to get samples cov- 
ering several years weather variations. Growing seasons differ 
from year to year, and the findings of one summer would not 
necessarily be applicable to the average season. A study covering- 
live consecutive years should reveal facts which can be applied 
generally throughout various weather conditions. The findings 
of this report cannot be considered conclusive but will be revised 
by the data from future years. Comparisons of the 1947 weather, 
with the average figures covering a period of more than 75 years, 
indicates that a departure from normal tended to produce condi- 
tions which would aid in the development of the various pollens. 
Studies are to be continued at 26 locations in the State, rather 
than at 12. This will provide a better coverage pattern, and enable 
this Division to better interpret the situation as it occurs. Reports 
of each years findings will be made at the time they are compiled 
and interpreted. At the completion of the entire course of the 
study, a final report will be made in an attempt to correlate the 
factors of the various seasons. 
58 Acknowledgements 
Acknowledgement is made to the following individuals and 
organizations for their assistance and full cooperation in the conduct 
of this study: 
United States Weather Bureau; New Hampshire Forestry and 
Recreation Department; New Hampshire Planning and Develop- 
ment Department. New Hampshire Fish and Game Department. 
The late Mr. William Roderick Macleod, whose keen interest 
and technical skill in microscopy contributed extensively to the 
success of this study. 
Dr. Matthew Waltzer, Chairman; and Mr. O. C. Durham, 
Technical Director; of the National Pollen Survey Committee of 
the American Academy of Allergy. 
Acknowledgment also is given to the following people for 
faithfully changing slides at the various pollen collection stations 
during the season: Grover Patten, Laconia; James Worsley, 
Whitefield; Reginald S. Evans, Warren; and Donald W. Ingram, 
Colebrook; all hatchery superintendents for the New Hampshire 
Fish and Game Department. The following private individuals 
maintained stations at their own time and expense: Dr. G. H. Shedd, 
Conway; Mr. J. C. Smith, Lebanon, Mr. H. Bassy, Lebanon; 
Mr. Evan White, Keene; Mr. C. Brodeur, Nashua; Miss F. 
Wojcizki, Exeter; Mr. C. Ross, Concord; Mr. E. J. Montminy, 
Berlin; and Professor F. E. Hodge of Colby Junior College. 
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THE CONCORD PRESS