52
M. E. D. POORE
and there is no doubt that criticism on this score is valid, if conclusions
are drawn which are more detailed than the data justify. This is not
usually the case in plant sociological literature. The published description gives, to any other worker experienced in the technique, an accurate impression of the actual vegetation, but analytical comparisons are
usually confined t o differences in presence or absence of species, and t o
large and consistent differences in abundance. Under these circumstances subjective estimation is not only justified but provides the most
economical way of obtaining the necessary data.
On the other hand very little attention has been paid t o the disadvantages of the more rigidly quantitative methods; these may be considered t o be excessively abstract and give false security.
Most statistical methods select a certain number of features of the
vegetation, number of shoots, basal area, height etc. which can readily
be measured, and examine these in great detail. The results are a
numerical presentation of these features abstracted from the total
biology of the plant community. Details of the vitality of species, the
mechanism of the plant community and its periodicity are often ignored.
The more qualitative the information, the more likely it is to be omitted
from any description. Yet these qualitative features are likely t o be
quite as important in an understanding of the place of the community
in the scheme of things.
Similarly the reduction of observations t o a table of figures may give
a sense of psychological security which is unwarranted by the method.
One might cite the example of vertical point quadrats which have been
very widely used in vegetation analysis, and which have recently been
shown by Warren Wilson (1960) to have a very wide range of error.
Neither of these disadvantages is inherent in statistical methods a5
such. Refinements of technique and fuller awareness of the total biology
of the community may minimize their effects. But they should not be
ignored in any assessment of the value of various techniques for the
study of vegetation.
There is a clear advantage in using rapid and standardized techniques
in regional vegetational studies. This facilitates the task of comparing
large numbers of descriptions. Their value is clearly shown by the advanced and organized knowledge of vegetation in those countries where
such techniques have been applied, as opposed t o those where a preoccupation with technique has stultified the extensive application of any
one method.
c. ABSTRACT UNITS O F VEQETATION
After following these procedures the ecologist’s note-book contains
descriptions of those communities which he thinks are uniform, and are
both typical of the region and occur frequently in it.
M. E. D. POORE
and there is no doubt that criticism on this score is valid, if conclusions
are drawn which are more detailed than the data justify. This is not
usually the case in plant sociological literature. The published description gives, to any other worker experienced in the technique, an accurate impression of the actual vegetation, but analytical comparisons are
usually confined t o differences in presence or absence of species, and t o
large and consistent differences in abundance. Under these circumstances subjective estimation is not only justified but provides the most
economical way of obtaining the necessary data.
On the other hand very little attention has been paid t o the disadvantages of the more rigidly quantitative methods; these may be considered t o be excessively abstract and give false security.
Most statistical methods select a certain number of features of the
vegetation, number of shoots, basal area, height etc. which can readily
be measured, and examine these in great detail. The results are a
numerical presentation of these features abstracted from the total
biology of the plant community. Details of the vitality of species, the
mechanism of the plant community and its periodicity are often ignored.
The more qualitative the information, the more likely it is to be omitted
from any description. Yet these qualitative features are likely t o be
quite as important in an understanding of the place of the community
in the scheme of things.
Similarly the reduction of observations t o a table of figures may give
a sense of psychological security which is unwarranted by the method.
One might cite the example of vertical point quadrats which have been
very widely used in vegetation analysis, and which have recently been
shown by Warren Wilson (1960) to have a very wide range of error.
Neither of these disadvantages is inherent in statistical methods a5
such. Refinements of technique and fuller awareness of the total biology
of the community may minimize their effects. But they should not be
ignored in any assessment of the value of various techniques for the
study of vegetation.
There is a clear advantage in using rapid and standardized techniques
in regional vegetational studies. This facilitates the task of comparing
large numbers of descriptions. Their value is clearly shown by the advanced and organized knowledge of vegetation in those countries where
such techniques have been applied, as opposed t o those where a preoccupation with technique has stultified the extensive application of any
one method.
c. ABSTRACT UNITS O F VEQETATION
After following these procedures the ecologist’s note-book contains
descriptions of those communities which he thinks are uniform, and are
both typical of the region and occur frequently in it.