416 BOTANICAL GAZETTE a [MAY 
and forest management, sawing and planting, felling and measurement, there 
are chapters on forest animals, birds, insects, weeds, and fungi. e fina 
chapter deals with the uses of British timber. The book is in an easily readable 
style and seems to give a good idea of forestry as practiced in Great Britain.— 
Geo. D. FULLER. 
NOTES FOR STUDENTS 
Vegetation and climate——The most recent phase of ecology, which finds 
expression in attempts to introduce quantitative methods for the investigation 
of vegetation and of the factors that determine its nature and distribution, 
has received a notable contribution in a recent volume by LivincsTon and 
HREVE.? ‘The existence, limits, and movements of plant communities are 
controlled by physical candittons” is stated as a fundamental law of plant 
geography, and an attempt is made to map the distribution both of various 
physical factors and of a considerable number of plants and plant communities. 
Data for the latter are obtained from a variety of sources, and more particularly 
from SHREVE’s well known map of the vegetation areas of the United States. 
In fact a generalized form of this map is employed as a basis upon which to 
display the distribution of climatic factors. In addition to this, ranges of 
various plant species and groups of species, such as deciduous, microphyllous, 
and broad-leaved evergreen trees, are delimited. Here emphasis is placed 
upon the lack of anything like an adequate knowledge of the ecological distri- 
bution, based on relative abundance, dominance, or density of stand, of any 
considerable number of plants even in such a well explored land as our own. 
general discussion of the influence of the environment on plant life 
classifies environmental factors which are important in distribution as: (1) 
moisture conditions, (2) temperature conditions, (3) light conditions, (4) 
chemical conditions, (5) mechanical conditions. These are considered in turn. 
In discussing the supply of water to vegetation the “residual soil moisture 
content” of the soil is not regarded as a soil constant, in spite of many data 
tending to prove that within very considerable limits its constancy holds. 
No mention is made of wilting or hygroscopic coefficients, nor of the notable 
contributions of such well known investigators as ALWAY, SHULL, KEEN, an) 
Bovyoucos. These omissions constitute be most serious defect in an other- 
wise admirable and comprehensive volum 
The tabulation of the climatological eae used for the construction of the 
mation regarding conditions limiting growth and distribution, the table of frost 
data may be cited. Here for 1803 different stations the altitude, number 0 
years of record, average date of the last frost in spring, and the earliest in the 
* LivINGsTON, B. E, and SHREVE, F., The distribution of vegetation in the 
United St ti Carn. Inst. Wash. Publ. 284; pp. Vit 
5090. pls. 73. figs. 74. 1921. 
