EESEAECH METHODS IN/'STUDY OF FOEEST ENVIRONMENT. 169 
growth particularly were too crude ; no means was at hand of 
determining closely when growth began, how rapidly it proceeded, 
when it ceased. In consequence, phenological observations have 
fallen into disrepute. 
The object of these conclusions is to suggest that, after all, in the 
study of ecology there is nothing more important than the behavior 
of the plant itself, its reactions at various times and seasons ; in other 
words, phenology in the fullest sense. Otherwise, ecological studies 
may as well be left to climatologists and soil physicists. 
How, then, may observations on the plant be made worth while? 
The observable external phenomena which accompany a reaction to 
certain environmental conditions must be measured more precisely 
than in the past if they are to serve any useful purpose. There is 
room here for instrumental development, quite as much as in the 
study of the environment. The field has been even more neglected. 
Again, there is opportunity for studying changes in the plant 
through internal physical and chemical conditions. This brings this 
study directly into the field of physiology, which can not be covered 
further than has already been done. Finally, experimental physi- 
ology, or the study of reactions to a limited change in environment, 
most of the conditions being stable and under control, is necessarily 
a laboratory study. The nature of the studies involved has been 
indicated in preceding discussions, especially in connection with 
light and soils studies. They ma} 7 have a very useful result in show- 
ing how better to study conditions in the field, but they do not take 
the place of field observations. The reactions produced by changing 
one factor while other conditions are more or less perfectly con- 
trolled, may not be at all the same as in the field where all the factors 
vary synchronously. After all, then, the problem for the ecologists 
simmers down to one of determining plant reaction in the field as 
closely as possible. 
In the past the plant society has perhaps been used too much as 
an index to reactions : that is. the effect of environmental conditions 
has been judged almost wholly by end results, in which competition 
plays an important part. A plant is either absent from a given site, 
occasional, abundant, moderately successful, or vigorous and domi- 
nant. From this is judged the extent to which the species is 
favored or inhibited by the environmental conditions that have been 
measured. This method is altogether too gross and undoubtedly has 
led to a great many erroneous conclusions. A great deal more is to 
be learned as to the requirements of different species by closer ob- 
servation of individuals. 
