Condition, Growth, and Projected Yield of Lodgepole Pine and Interior Spruce 20 Years After Rehabilitation of an Understocked Site in North-Central British Columbia: The Stony Lake Trial

Authors
Roger Whitehead
F. Cortini
S.W. Taylor
A.F. Linnell Nemec
J.W. Goudie
J. Vallentgoed
K.R. Polsson
Resource Date:
2011
Page Length
19

The Stony Lake trial was established in 1987 to benchmark growth performance of interior spruce (Picea glauca [Moench] Voss x engelmannii Parry ex Engelm.) and lodgepole pine (Pinus contorta Dougl. Ex Loud. Var. latifolia Engelm.) planted into 12 treatment regimes for rehabilitating an understocked sub-boreal spruce site (SBSwk1). All combinations of three options for primary site clearing treatments (burn, spray and burn, or windrow), two options for secondary site preparation treatments (disc-trenching or no disc-trenching), and two options for tertiary weeding treatments (broadcast application of herbicide three years after planting or no treatment) were tested. Twenty years after planting, both species had high survival (> 90%), but pine showed much less evidence of damage that could affect future survival or sawlog form than interior spruce. Pine saplings were 57-82% taller and 28-58% larger in diameter than the spruce. Mean total stand volume ranged from 61 to 112 m3/ha for lodgepole pine, with 10 out of 12 treatments yielding > 95 m3/ha at 20 years. Total volume for interior spruce ranged from 28 to 52 m3/ha. High levels of leader weevil damage made it inappropriate to use the Tree and Stand Simulator (TASS) to project future growth for spruce, but simulations for pine predicted yields of at least 300 m3/ha (merchantable volume) between 40 and 50 years after planting for all but one treatment combination. In addition, growth advantages observed in the first 20 years were associated with a yield of higher stand volume and larger logs with potential for a higher recovery of value at harvest. Our results suggest that establishing plantations of lodgepole pine during rehabilitation of similar sites will require fewer entries than interior spruce and produce larger trees and higher stand-level volumes much earlier.