Agriculture Reference
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product sinks (and exported C) and additional C sequestered as a result of
forest management activities (
e.g.,
juvenile spacing, commercial thinning
and fire control). Even when all of the C fluxes are appropriately taken into
account, it is unlikely that 'additional' forest management will be a cost-
effective and competitive means for sequestering carbon (Caspersen
et al.
2000).
2
Evidence from Canada, for example, indicates that reforestation
does not pay even when C uptake benefits are taken into account, mainly
because northern forests tend to be marginal (van Kooten
et al.
1993). The
reason is that such forests generally regenerate naturally, and returns to
artificial regeneration accrue in the distant future. Only if short-rotation,
hybrid poplar plantations replace logged or otherwise denuded forests
might forest management be a competitive alternative to other methods of
removing from the atmosphere. Hybrid poplar plantations may also be
the only cost-effective, competitive alternative when marginal agricultural
land is afforested (van Kooten
et al.
1999).
Surprisingly, despite the size of their forests and, in some cases,
large areas of marginal agricultural land, there remains only limited room
for forest sector policies in the major wood producing countries (Canada,
Finland, Sweden and Russia). We illustrate this using the TECAB model
for northeastern British Columbia (Stennes 2000; Krcmar and van Kooten
2001). The model consists of tree-growth, agricultural activities and land-
allocation components, and is used to examine the costs of C uptake in the
grain belt-boreal forest transition zone of BC. These estimates, extended to
similar regions, provide a good indication of the costs of an afforestation-
reforestation strategy for C uptake for Canada as a whole, and likely for
other boreal regions as well. The study region consists of 1.2 million ha, of
which nearly 10.5% constitute marginal agricultural land, with the
remainder being boreal forest. The boreal forest is composed of spruce,
pine and aspen.
For environmental reasons and to comply with BC's Forest
Practices Code, the area planted to hybrid poplar in the model is limited
only to logged stands of aspen and marginal agricultural land. Other
harvested stands are replanted to native species or left to regenerate on
their own, depending on what is economically optimal. Carbon fluxes
associated with forest management, wood product sinks and so on are all
taken into account. An infinite time horizon is employed, land conversion
is not instantaneous (as assumed in some models), C fluxes associated with
many forest management activities (but not control of fire, pests and
disease) are included, and account is taken of what happens to the wood
after harvest, including their decay (see Table A.2 for data on decay of
forest ecosystem components).
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