Roads, trails and landings are needed to access timber and other benefits of the forest, but excessive access development can have negative consequences as well. Rehabilitation of access structures improves forest productivity, improves soil hydrologic function, and reduces the risk of erosion. Rehabilitation can also facilitate a wider range of harvesting options that can reduce costs. In many parts of BC, development of access management strategies requires decisions about short- and long-term road use: should roads remain open, should they be deactivated with the option for future use, or should they be rehabilitated and a new forest established. Such decisions rely on long term data on the productivity of roads and landings that in many cases were restored using a variety of methods.
Several trials have been established over the past twenty years to evaluate the productivity of rehabilitated roads, trails and landings. Short-term results have been reported and have been guiding decision making for a number of years (e.g. Bulmer and Krzic 2003, Sanborn et al 2004, Dykstra and Curran 2000). Despite the progress made and lessons learned to date, reliance on short-term results for long-term decisions can be unreliable. In soil disturbance studies in BC and elsewhere, short-term results are not always good predictors of longer-term effects (e.g. Wass and Senyk 1999; Morris and Miller, 1994). For this reason, long-term measurements are essential.
This project aims to use existing study plots in the BC interior and collect up-to-date measures of tree growth and productivity. Over a three year period, we intend to visit sites in the northeast, south-central and southeast interior to update existing tree growth information. In the BWBS zone of northeast BC, a retrospective study was carried out in 2001 to evaluate the productivity of 24 landings that were rehabilitated with a winged subsoiler in 1994 and planted with lodgepole pine in 1995. The work was carried out operationally with the intent of increasing forest productivity on the disturbed areas. Five years later, sixty percent of landing subplots had more than 1000 well spaced stems per ha. Only 9 percent of landing subplots had less than 600 well spaced stems per ha. Stocking was higher for mesic and sub-xeric sites compared to sites with a sub-hygric moisture regime. Trees in plantations appeared to be growing slightly better than those on the rehabilitated landings (Bulmer and Krzic 2003). Our plan is to revisit these sites in 2007 (year 12) and collect growth measurements to document their performance since 2001. In the MS and ESSF biogeoclimatic zones of south-central BC near Kamloops, 31 rehabilitated landing and road segments were evaluated in 2001 and 2002 for site characteristics, soil properties, and tree growth response. The sites had been operationally rehabilitated over the preceding 10-15 years, and were stocked with lodgepole pine. Site index on both roads and landings in the MS and ESSF appeared to be no different than in the adjacent plantations, despite a trend towards slightly higher stocking on the landings. Our plan is to revisit these sites in 2007 and 2008 and collect 15 20 year growth measurements to document their performance since 2001. In the ICH, MS and ESSF zones of southeast BC, productivity of trees growing on reclaimed skid trails was evaluated at ten locations in 2002 and 2003. The trees growing on the berm and undisturbed treatments commonly displayed better growth than the trees growing on the inner track and midroad treatments. Trees growing on the berm were either the leading or second ranked treatment in seven out of 10 blocks, with differences in growth relative to the undisturbed ranging from 89 to 161%. Diameter and volume growth followed the same trend as height for all analyses. Our plan is to revisit these sites in 2008 and 2009 (16 years) and collect growth measurements to document their performance since 2003.
Bulmer, Charles E.. 2008. Restoration of forest soils: long term productivity results. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report
Topic: FLNRORD Research Program
Keywords: Forest, Investment, Account, (FIA), British, Columbia
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