Document Details
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Title |
Development of residual trees and regeneration following MPB attack in thinned lodgepole pine stand | ||||||||
Author |
Brockley, Robert P. | ||||||||
Date |
2008 | ||||||||
Abstract |
Beginning in 1982, a series of long-term thinning experiments (EP 922) were established by the B.C. Ministry of Forests, Forest Science Program to document the growth and yield impacts of a wide range of post-thinning stand densities in early- and mid-rotation, fire- and harvest-origin lodgepole pine stands in the B.C. interior. A total of 11 lodgepole pine installations are distributed among four biogeoclimatic (BEC) zones (IDF, MS, SBPS, SBS). Stand ages ranged from 7 to 60 years old at the time of trial establishment. The field installations test 4 or 5 post-thinning densities (500 to 3000 stems per hectare) plus an unthinned control. Each of the treatments is replicated two or three times at each of the study sites. In the early fall of 2005, several of the lodgepole pine EP 922 field installations were visited to determine whether they had been attacked by the MPB. During these visits, it was confirmed that a large percentage of the trees within treatment plots at several of the study sites had been attacked by the MPB in the summer of 2005 (?green attack?). The current ages of attacked stands range from 28 to 79 years. These damaged EP 922 field installations provide an excellent opportunity to document post-attack stand dynamics in unsalvaged, thinned, pine-dominant lodgepole pine stands in the B.C. interior. We are documenting the pattern and progression of attack, mortality, and fall down rate of overstory trees, and the growth and development of surviving residual trees, in all of the thinned and control plots at two EP 922 study sites ? a young harvest-origin stand and an older fire-origin stand. We are also quantifying, characterizing, and measuring the advance regeneration that exists at the time of beetle attack and the subsequent ingress and development of natural regeneration following attack. This project is progressing with only minor deviations from the originally approved project. Upon field inspection in the spring of 2006, it was determined that one of the proposed study sites (EP 922-4, Strimboldh Creek) was, in fact, not attacked by the MPB in 2005. This 78-year-old, fire-origin stand was replaced with an 80-year-old, fire-origin stand within the SBSdk BEC subzone southwest of Burns Lake, B.C. (EP 922-6, Takysie Lake) that was attacked by the MPB in 2005. Post-thinning treatments, sizes of thinned plots, and replication at the Takysie Lake site are identical to the Strimboldh Creek study site. Minor adjustments to the proposed experimental methodology are described in the Experimental Design and Methods section. | ||||||||
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