Heat-Pulse Velocity and Bordered Pit Condition in Living Engelmann Spruce and Lodgepole Pine Trees

Abstract

The purpose of this study was to correlate sap movement and ultrastructure of wood. Heat-pulse velocity measurements indicated a low flow in the vicinity of the cambium, a peak flow in the region from 30 to 42 mm from the cambium, and a tailing off of flow as the distance from the cambium increased. Bordered pits located in the area of peak sap movement were not aspirated and were only partially incrusted. Pits located in the area of low flow near the cambium were immature and nearly imperforate, whereas those in the area of low flow deep within the trees showed a high frequency of aspiration or nearly complete incrustation. Forest Sci. 19:291-296.