The last Timber Supply Review (TSR)
reduced the Annual Allowable Cut (AAC) in the Nelson
Forest Region from 6.0 million m3 per year to 5.5
m3 per year. The implementation of the Kootenay Boundary
Land Use Plan (KBLUP) is expected to reduce the AAC to
between 4.7 and 5.2 million m3/year. This represents a 13.3
percent to 21.7 percent drop in AAC. The implementation of
the KBLUP may translate into a projected loss of 450-560 direct
jobs and $10.5 million of direct stumpage per year.
A greater reliance on partial cutting
systems, compared to clearcutting, may minimize the wood supply
fall downs while addressing the management requirements of other
resources. The Chief Forester has indicated that before commercial
thinning impacts could be considered in future TSRs, candidate
commercial thinning stands must be identified, a commercial thinning
strategy must be developed and the impacts of a commercial thinning
program on the timber supply must be assessed.
The main objectives of this project
were to:
This project addresses some of the
Chief Forester's recommendations in the context of the recently-approved
Kootenay-Boundary Land Use Plan by providing a framework for developing
a commercial thinning strategy using Arrow and Cranbrook as pilot
TSAs. The framework can be modified to suit the specific conditions
and objectives of other TSAs as required. It consists of identifying
utilization and economic criteria, theme mapping to identify potential
areas, field inventories of potential areas to identify actual candidate
stands and wood supply modelling to test the effects of various
levels of commercial wood flow.
Theming initially identified approximately
44,557 hectares of potential stands in the Arrow TSA and 24,843
hectares in Cranbrook TSA. Lack of road access subsequently eliminated
approximately 85 to 90% of the themed stands as potential candidates
for thinning. Reconnaissance surveys in the accessible stands indicated
that approximately 80-90% of the stands surveyed were unsuitable
for thinning, mainly due to inappropriate stand structure or low
potential thinning volumes. Only a subset of surveyed stands was
cruised in each TSA. The cruising identified between 10,298 and
14,195 m3 of potential thinning volume in Arrow TSA and 32,650 to
41,704 m3 in Cranbrook TSA, depending on the minimum utilization
level. However, District staff anticipate that only 40-60% of the
cruised stands may actually be thinned due to stand structure and
overriding management objectives.
Resource
Emphasis Area (REA) management objectives, current
stand structure, biological potential of the stand to maintain adequate
growth after thinning and utilization level by species must all
be considered when developing thinning prescriptions. There are
trade-offs between potential thinning volume, stand growth and forest
health depending on the emphasis of any of these factors.
In the Arrow TSA, at 2 to 5% increase
in short term wood supply was indicated by the modelling when the
thinning was concentrated in visually constrained Resource Emphasis
Areas. The positive effects on wood flow were maximized at 400 hectares
per year but were only suitable for the first six decades. The increase
in wood flow attributed to commercial thinning is not additive
to the increase from other partial cutting practices in constrained
areas. Some of the benefits may already be realized due to the amount
of partial cutting currently being practiced.
At the forest level, there appears
to be an optimum balance between clearcutting and partial cutting
systems that maximizes wood flow, but it varies by landscape unit,
silviculture and management constraints. Both the timing and location
of the partial cutting is critical, and if it is not targeted in
the most constraining landscape units and REAs, the positive impacts
on wood flow will not be achieved.
Link to Definitions:
1. Commercial Thinning
Commercial thinning is a form of partial
cutting that is defined as the removal of a portion of the trees
in which all, or a portion, of the felled trees are extracted for
useful products, regardless if their value is great enough to defray
the cost of the operation. Commercial thinning is typically done
in stands that are not mature or that are younger than the minimum
harvest age.
At the stand level, commercial thinning can:
2.
Resource Emphasis Area
Resource Emphasis Areas (REAs), developed
by the Ministry of Forests and the Ministry of Environment, Lands
and Parks for the KBLUP, allow different maximum levels of basal
area removals to meet their specific management objectives. The
REAs are hierachical and the guidelines apply to mature stands.
REAs, in order of hierarchical priority are: caribou habitat, VQO
Retention, VQO partial retention, community watershed, domestic
watershed, ungulate winter range and integrated resource management.
