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Abstract
Understanding crown rise and sapwood taper will help meet management objectives such as producing long branch-free boles for clear wood and old-growth restoration, or producing sawlogs with a high proportion of heartwood. Coast redwood (Sequoia sempervirens) tree crown ratio data were collected 20 years after partial harvesting in a 65-year-old second growth stand. Crown ratio correlated with stand density and relative tree height, and differed between stand interior and edge locations. The sum of tree crown lengths in each plot gave crown length/ac which exhibited an asymptotic relationship with stand density (i.e., crown length/ac peaks at higher densities). Maximum crown length/ac can be used to constrain simulations of crown rise by limiting the increase in crown length following thinning. Sapwood cross-sectional area was sampled at breast height and at the base of the live crown (BLC) of redwood trees growing in northern, central, and southern portions of redwood’s natural range. Variability in sapwood area taper prevented detection of significant differences between regions, but on average sapwood tapered most rapidly among northern trees and least among southern trees. We present a robust sapwood taper model derived from the power function that has the desirable property of predicting zero taper for trees with BLC at breast height. Models predicting sapwood area at breast height from DBH allow prediction of sapwood from forest inventory data. Results indicated that dominant and codominant trees in the northern region had more sapwood than trees of similar size growing in the hotter, drier southern region.
Parent Publication
Citation
Berrill, John-Pascal; Deffress, Jesse L.; Engle, Jessica M. 2012. Coast redwood live crown and sapwood. In: Standiford, Richard B.; Weller, Theodore J.; Piirto, Douglas D.; Stuart, John D., tech. coords. Proceedings of coast redwood forests in a changing California: A symposium for scientists and managers. Gen. Tech. Rep. PSW-GTR-238. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture. pp. 473-484.
