Seedlings of Douglas fir, grand fir, western larch, western red cedar, and western white pine were grown in modified environments for four growing seasons to see whether characteristic growth responses of roots and shoots might suggest a cause for pole blight of white pine. Environments included three soil profiles (topsoil, hardpan, and rock) and two moisture regimes (adequate and deficient). Of several variable characteristics of growth, total root weight was the only significant source of variation in diameter and height growth of white pine. Of all five species, white pine also appeared least efficient in competing for moisture on all soil types and was least able to adapt to soils having inadequate available moisture and low potential for recharge. The lack of response to poor environment can result in imbalance of root/shoot ratios. If this imbalance of root/shoot ratios can subsequently cause internal physiological stresses during droughty periods, these stresses, in turn, may cause deterioration of the root system and consequent decline in tree vigor, both of which usually precede appearance of pole blight.