Daily height increment of trees was measured throughout two growing seasons as was 2-day radial increment of 212 of the same trees in the second season. The relationships between phenological variables and total growth, and the effect of environment on short term growth were assessed. Inferences taken from the latter data were tested on seedlings under more controlled conditions in the laboratory. The arbitrarily defined dates of initiation and cessation of growth, and the grand period growth rates were read from the growth curves. The respective simple r2 values between these variables and height growth were 0.10, 0.40, and 0.71, and r2 for the multiple regression of height growth and these variables was 0.94; for radial growth these values were 0.07, 0.56, 0.64, and 0.94. Length of the growing season and grand period growth rate were positively correlated. Dates of growth initiation and growth cessation were also positively correlated.Daily height growth varied considerably, depending strongly on temperature and relative humidity. The latter was associated with both a change in growth rate and a physical (nongrowth) change in size. Radial growth varied less, and depended less on environmental conditions. Minimum daily radius occurred several hours after the occurrence of maximum xylem sap tension.In seedlings, dimensional changes were very rapid on change of water stress. Day height growth rate was higher than night growth rate, presumably because of current photosynthate use.