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I just read a recent article in Forest Ecology and Management that examines the optimal strategies for maximizing carbon in forests, forest products and abating emissions through product substitution.
The authors present their findings as an argument for why we should include carbon stored in harvested wood products in our accounting and therefore our policies to reduce GHG emissions from forests. I see these results completely differently:
to me it is a clear illustration of precisely why we should not embrace this approach.
In a previous blog post, I argued that our carbon policy objective for forests should be to maximize forest carbon as this sector’s contribution to an overall climate change mitigation plan. I argued that the pulp and paper industry is in the business of transforming forest carbon into wood product carbon and that one of the impacts of this enterprise is depleted forest carbon stocks. A value placed on forest carbon stocks would create incentives for forest managers to redress this impact while they continue to extract products from the forest.
This article illustrates my point: Managing to maximize forest carbon results in decreased harvest levels, longer harvest rotation ages and older forests. On the other hand, maximizing total carbon stocks (forest carbon + product carbon) diminishes this effect: Clearcutting increases by 40%; rotation ages decrease (though are still substantially longer than business as usual); harvest levels increase 173% compared to scenarios that maximize forest carbon.
What is the dividend for this massively increased pressure on the forest? A five percent increase in total carbon stocks. FIVE percent. And where is most of this carbon? By the end of the 200 year modeling window, 80% of it is in landfills. Even considering the benefits of abated emissions coming from substituting wood for more energy-intensive materials the carbon dividend of this strategy is only six percent.
Finally, these carbon benefits reflect the long-term result after 100 and 200 years of modeling. What if we acknowledge the importance of emission reductions now, when action on climate change is so urgent? Modeling the impact of a four percent discount, the authors find that no harvesting would take place when maximizing forest carbon and 67% less harvest would occur when maximizing total carbon (forest carbon + product carbon).
There are two take home messages for me in this paper:
- Mixing product carbon into markets and policies could result in a significant increase in pressure on natural forests for very little carbon dividend.
- There is a potential to distort climate policies to support increased wood production even if it results in increased emissions in the short-term when we most badly need mitigation.
Resources:
Hennigar, C.R., D.A. MacLean and L.J. Amos-Binks. A novel approach to optimize management strategies for carbon stored in both forests and wood products. Forest Ecology and Management 256 (2008): 786-797.
This study was carried out in a hypothetical 30,000 ha Acadian forest in New Brunswick, Canada, containing softwood, hardwood and mixed wood stands.
Photo credit: Ralph Eldridge
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