Patterns of Water Movement in Forest Trees

Abstract

1. Experiments were conducted in central and north-central Wisconsin on paths of upward water movement in stems of trees unilaterally injected at the base with acid fuchsin dye. The path of uptake was traced by felling the injected trees and observing the pattern of dye staining in horizontal 1-inch-thick cross-sections of the stem taken at intervals of 2 feet along the stem. Four species of gymnosperms and seven of angiosperms were studied. 2. Marked variations in paths of water movement were observed among genera and species. There also was considerable variation in patterns of dye ascent among individual trees of certain species, but in other species the pattern among trees was very consistent. 3. Deviation in water movement from a vertical path was more common over a wide range of species than was strictly vertical water transport. Some tendency for spiraling of water in its ascent was observed in all species studied. 4. Patterns of water movement were correlated with spiraling of xylem elements. Hence, the path of ascent may be predictable by analyzing spiral grain in trees. 5. In ring-porous angiosperms water transport was confined to a thin cylinder of the outer sapwood, while in diffuse-porous angiosperms and in gymnosperms the path of ascent involved a much greater proportion of the sapwood. 6. Variations in the path of water movement are discussed in relation to transmission of vascular wilt diseases.