A formal growth and yield research trial was initiated in 2001 on a poor growing lodgepole pine (Pl) stand in the Northern Interior of British Columbia. This report describes the response of the stand to treatments four years after treatments were imposed. The stand developed on a moist to mesic, fine-textured site within a 23 year-old wildfire, known locally as the Swiss Fire near Houston BC. The trial was designed to look at response of a 15 year-old Pl problem forest type (PFT) stand to innovative and conventional silviculture treatments to see if poor growing stands respond positively to treatment. As PFTs are currently removed from the THLB, it was decided that more research was needed to determine whether such PFTs have greater site growth potential than expressed by the repressed Pl stand category that currently exists. The stand being studied is approximately 22 years old and very dense (~50,000 sph), approximately 1.5m in total height and has an estimated Site Index of 6.6m/50 years. Such a stand fits the category of non-merchantable, low site or PFT, given current harvesting/utilization standards (Yole, 2001). Left untreated, this stand would not be expected to be merchantable in size in less than 150 years. This trial was designed and installed in an attempt to reveal what factors are limiting growth and whether treatments can eventually lead to a productive stand that will contribute to the THLB. The four?year results of this study are showing that this PFT stand is responsive to treatment and that both rehab and subsoiling treatment show an increment growth improvement over the untreated condition. Juvenile spacing appears to improve height increment growth significantly in the short term (stems reduced from 50000 sph to 1600 sph). Height increment growth was not significantly improved by the subsoiling treatment. However, the significant improvement in soil nutrient status and aeration in the upper root zone should help boost growth in the future.
by David W. Yole.
Yole, David W.. 2006. Fourth year post-treatment response for a problem forest type research trial. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2006MR185