Sunscald of Eastern White Pine, Pinus Strobus L.

Abstract

Many eastern white pine trees (Pinus strobus L.) standing on the edge of cuttings often show dead strips of bark on their sun-exposed sides. In many cases the dead bark peels off, exposing the sapwood, or appears merely as a depressed discolored area. The injury apparently is seldom serious enough to kill the tree, but because of the exposed area and the formation of callus tissue on its edges, it seriously degrades logs. It may provide entrance to fungi and boring insects which can damage the rest of the tree and endanger the remainder of the stand. A similar injury called sunscald is well known in fruit orchards, especially on apple, peach, and cherry trees, and is thought to be traceable to the combined action of sun and low temperature during the winter. It is difficult to estimate the extent of the damage from this injury in terms of board feet. However, injured trees have been observed throughout the white pine region of New England, and in plantations outside this region. Old-time operators in Maine and New Hampshire talk about sun-scorch as something that always hits white pine left after cutting. This is a somewhat exaggerated picture of the importance of the injury because only trees immediately adjacent to the northern or eastern edge of cuttings or along roads are likely to be even