CHAPTER IV. THE PLANT FORMATION 
Metruons oF INVESTIGATION AND REcORD 
198. The need of exact methods. The use of instruments in the study of 
the habitat has made it evident that the loose methods of descriptive ecology 
were altogether inadequate to the accurate investigation of the formation. 
This feeling has been heightened by the recognition of the fact that vegeta- 
tion exhibits both development and structure, and is, in consequence, open 
to exact methods of inquiry. In the search for feasible methods, it was 
quickly seen that the quadrat, first! used for determining the abundance of 
species, furnished the key to the problem. Accordingly, the principle un- 
derlying it, viz., that of intimate detailed study and record, was developed 
and extended in such a way as to give rise to a number of methods of 
precision. These have been applied in the field for several years with 
signal success, and they are here described in the conviction that they con- 
stitute a satisfactory svstem, if not, indeed, the only one for the exact study 
of formations. j 
There has been a growing appreciation of the fact that the superficial 
methods of descriptive ecology made it impossible to build upon such a 
foundation, and they, indeed, were making actual progress in the field of 
ecology more and more difficult. Ecologists have now begun to see clearly 
that precise methods are as indispensable in the habitat as they are to the 
study of the structure and: modification of the plant. For some reason, 
‘however, they have been slow to perceive that accuracy in the investigation 
of the cause, the habitat, is a fruitless task unless it be followed by corres- 
ponding exactness in the study of the effect, the formation. After having 
utged the fundamental necessity of instrumental methods, for six or seven 
years, both in season and out of season, the writer does not feel called 
upon to further plead the cause of the quadrat. The final acceptance of the 
instrument was inevitable if progress were to be made in.the habitat, and 
it is just as obvious that the quadrat must be accepted if the study of the 
habitat is to bear fruit in the interpretation of the formation. The use of 
the quadrat does not mean that the general methods of descriptive ecology 
are all to be discarded, whether they have value or not. The statement that 
quadrat methods are indispensable signifies merely that they must be used 
for research work in the development and structure of vegetation. They are 
1PoUND AND CLEMENTS. A Method of Determining the Abundance of Secondary 
Species. Minn. Bot. Studies, 2:19. 1898. 
