Research Branch Staff Publications

Sap flow in old lodgepole pine trees.

Citation:

Spittlehouse, D.L. 2002. Sap flow in old lodgepole pine trees. Proceedings 25th Conference on Agricultural and Forest Meteorology, 20-24 May 2002, Norfolk Virginia, American Meteorological Society, Boston, MA, pp. 123-124.

Abstract:

Thermal dissipation probes were used in determining sap flow in lodgepole pine trees from June to October 2000 at a high elevation site in the southern interior of British Columbia, Canada. Hourly weather data, rainfall interception by the lodgepole pine and root zone water content were also measured. Sapwood area was measured on each tree to give total flow and was scaled to the stand level using stem diameter distribution. Daily sap flow for large trees on sunny days was over 50 L d-1, 3 to 4 times that of smaller trees. Daily sap flow showed linear or slightly non-linear relationships between trees with R2 > 0.94 in most cases. North and south side flows showed similar excellent agreement. Mean daily forest evaporation varied from 2.4 mm d-1 in June to August to 1 mm d-1 in late September. The trees and the below canopy vegetation contributed 42% and 25%, respectively, of the total evaporation. 28% of the rainfall was interception and this comprised 33% of the total evaporation.

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