260 TRANSACTIONS OF THE 
RELATION OF PRECIPITATION TO HEIGHT 
GROWTH OF FOREST TREE SAPLINGS. 
BY CLARENCE F. KORSTIAN.1 
In passing through stands of coniferous saplings five 
to twenty feet tall, surprising variations are noted in the 
distance between the whorls of branches. The dis- 
tance between whorls, usually corresponding with 
the internodes, represents the amount of height growth 
made during a given growing season. The growth of 
each season for the past thirty or forty years can be deter- 
mined by measuring the length of the internodes. Var- 
ious explanations supported by experimental data have 
been offered as to the cause of these variations, the most 
common and logical of which have taken into account the 
environmental conditions, especially the moisture relations 
between the plant and its habitat. The relation between 
the loss of water from the plant, or transpiration, and the 
available moisture supply of the soil is of vital importance 
in regions where arid or semi-arid conditions are prev- 
alent. Probably the most satisfactory expression or sum- 
mation of moisture conditions is to be found in the ratio 
between the evaporating power of the air and the avail- 
able soil moisture as proposed by Fuller.2 Unfortunately 
neither of these factors can be used in the discussion at 
1U. S. Forest Service. 
2Fuller, Geo. D. Evaporation and Soil Moisture in Relation to 
the Succession of Plant Associations. Botanical Gazette 59: 
198-234. 1914. 
