UTAH ACADEMY OF SCIENCES 191 
ficial reforestation or through natural reproduction. If 
the life histories of our forest trees were thoroughly known, 
many of the methods of handling our forests would have 
been determined. 
2. Studies of the relation of tree life to the physical 
and climatic factors of the habitat which go into the basic 
causes of the biological characteristics of forest trees, 
Studies of the relation of light, climate and soil to tree 
growth are now under way. 
3. Volume, growth and yield studies of individual trees 
and stands, which embrace the laws of the growth of in- 
dividual trees and stands. This field of investigation has 
been barely entered. There is a great opportunity for 
developing basic principles which will simplify the methods 
of the regulation and management of our forests. 
4. The ecology of virgin forests, which includes a 
study of the relation between forest types or associations 
and their physical conditions of growth. This group is 
really an extension of the studies of life histories of in- 
dividual trees to entire stands. When further progress 
has been made these studies should furnish a solid basis for 
the silvicultural management of our different forest types. 
5. Studies of ecological succession on cut-over, burned- 
over, and culled forest areas. Studies of what actually 
takes place after a virgin forest is cut-over, or burned un- 
der the prevailing climatic and physical conditions of the 
region afford the best opportunities for establishing definite 
relations between a method of cutting and natural repro- 
duction. Such studies also provide a basis for the rational 
determination of the suitability of the site for artificial 
reforestation and the species to be used. 
6. Studies of the organic and climatic enemies of 
forest trees. The study of the organisms which injure 
forest trees is really a field for the forest pathologist, 
forest entomologist, and forest zoologist, while the study of 
the effects of snow, hail, wind, sun-scald, lightning and 
other climatic factors upon trees properly belongs to the 
forester. 
