344 
The Ohio Naturalist. 
[Vol. VIII, No. 7, 
canadensis, etc., a few small oaks, and Acer rubrum as the dom¬ 
inant form. An interesting comparison is afforded when we 
note that the country surrounding the lake and especially the 
northern shore near the bog-island supports at various places 
a forest vegetation in the form of woodlots. The most common 
trees are the beech, elm, maple, oak, chestnut and walnut,— 
examples of a temporary mesophytic climate society. 
In determining the influence on annual accretion of wood the 
stumps of red maple were selected. A number of these trees 
had been just recently felled both in the bog and on the shores near 
by. It seemed desirable therefore to procure and record data 
on measurements from such trees of the two conditions of hab¬ 
itat, as were nearly the same in size, age, uniformly concentric 
growth of wood, and general environment. The general climate 
is assumed to be almost identical for both places, and being thus 
eliminated, it became more easy to determine the effect of 
edaphic conditions upon the rate of diameter growth of the species. 
From the number of trees at disposal five were selected from 
the marginal bog-zone, and three were chosen from the wood- 
lots near the shore. It may be objected that not enough trees 
were analyzed to permit the conclusion drawn. In order to 
eliminate sources of error, measurements were made, indeed, on 
a larger number of sample trees. To the writer, however, it 
seemed that the degree of confidence and the accuracy of the 
statistical result depended not so much upon numbers, as upon 
the functional criteria of the environment. It was not so much 
the object of this study to establish variability, as to find a 
suitable method of determining the influence of various factors 
in the environment. A method was sought by which temper¬ 
ature, light, humidity and soil data could be combined in a 
single number. The fact that so large a part of plant activities 
and adaptation is directly or indirectly connected with climatic 
and edaphic factors, suggested that if a comparative and statis¬ 
tical study of secondary growth on similar trees of various pro¬ 
nounced habitats were made, a new basis for determining climatic 
and edaphic regions of optimum development would be at hand. 
Put in tabular form the results of the measurements are as 
follows: 
Width of Rings 
in mm. 
i. 
1.5 
2. 
2.5 
3. 
3.5 
4. 
4.5 
5. 
5.5 
6. 
6.5 
7. 7.5 
8. 
8.5 
9. 
9.5 
10. 
Tot. 
Frequencies in 
Bog habitat 
16. 
10. 
23. 
20. 
27. 
12. 
20. 
5. 
7. 
5. 
5. 
5. 
1 
6.1 1. 
1 
2. 
0 . 
1 . 
0 . 
2. 
167 
Frequencies in 
Woodlots 
2 , 
30. 
31. 
9. 
6. 
1 
1 
1 
102 
