RESEARCH METHODS IX STUDY OF FOREST ENVIRONMENT. 173 
Ity, insolation, wind exposure, etc., be witnessed by photographs and 
topographic map. The former should be taken from as many posi- 
tions as possible to show the general position of the station with re- 
spect to topographic features, to show the position of the trees which 
may influence atmospheric factors, to furnish a map of the canopy 
(by vertical view) which affects the insolation at the ground, and 
finally to show in detail the nature of the ground and ground cover. 
The view of the canopy should be taken as nearly as possible from the 
position which will be occupied by solar apparatus and evapori- 
meter. 
The local topographic map should be made on a scale adequate to 
show in detail the immediate surroundings and those which are close 
enough to have appreciable effect on insolation, wind velocity, etc. 
Especially when two or more stations in close proximity, but different 
presumably in some essential aspect, are being studied, should the 
map be made full enough to bring out clearly the contrast which 
exists in conditions. In such cases a joint map for the several sta- 
tions may well be used. Such maps should, if possible, be restricted 
to the size of the tabulating forms used. 
Form 1. 
[U. S. Forest Service, Physical Survey.] 
DESCRIPTION OF OBSERVATION POINT, LIMITED AREA, TREE ENVIRONMENT. 
Project ■ 
Station No Area involved 
Forest type Absolute elevation 
Permanent sample plot No Block No 
National Forest Nearest post office 
County State 
Legal location Exact location 
TOPOGRAPHIC FEATURES. 
Aspect Gradient 
Distance from ridge Distance from channel 
Elevation above water Wind exposure 
Air drainage conditions 
Elevation of horizon to east ; west ; north ; south 
Character of topography 
FOREST ENVIRONMENT. 
Distance of nearest trees to north ; east ; south ; west 
Age of trees Height 
Diameter Trees per acre 
Stand, feet b. m Stand, cubic feet 
Growth rate ; height, diameter, or cubic feet per A. A 
Shading, amount From trees on 
Tight at the ground, per cent Determined by 
