I’ve just published a discussion paper to share with you all: “A Proposed Methodology for Assigning Sequestered CO2 from “Climate-Friendly” Forest Management to Timber used in Long-Lived Building Products.”
As the rather wordy title suggests, it is about trying to bring the impacts of forest management into LCA and EPDs for wood products in buildings.
This is not intended to be the last word on this topic - actually, very much the reverse. This is just the current thinking we have based on current project work in this area, and it relies a lot on the excellent work to date of David Diaz & co at EcoTrust. We know that work is ongoing, and that would be one reason to expect this approach to change in the future, but there are probably other things to include in a methodology for putting forestry into LCA… would definitely appreciate your thoughts. I hope that those of you working in the field will use this paper as a point of reference – it is not so much intended to have a methodology to use directly on projects (though you are welcome to try), but to advance our collective approach to include more relevant factors and information. You’re welcome to point out oversights or alternatives that are just as good or better. Hopefully, a robust discussion will help us all grapple with this difficult question better.
Hi Raphael - this is a great initiative, and is referenced in the Upstream Carbon Tool.
I have a couple of comments as follows:
The research by Diaz et al. is strictly limited to even aged stands, so all conclusions drawn from their work would necessarily exclude old-growth logging or land use change. Although the report is implicitly dealing with sustainable timber, I think it is worth making this crystal clear – particularly for the Canadian market where old growth logging continues (unfortunately).
Some of the so called sustainable forestry practices listed as benefits by Diaz et al. are problematic, especially replanting with genetically superior planting stock – we know that the forestry industry replant with clones selected for fast growth, but this has lead to a reduction in genetic diversity leaving the forests susceptible to attacks from beetles and fungi, etc.
The other major limitation of Diaz et al. as well as other forestry studies (e.g., CORRIM) is that they only include the above ground carbon accounting of saleable timber stock, and completely ignore below ground carbon sequestration, as well as the understorey (probably this is less important in even aged plantation forests). There is also an issue of attribution of carbon when a tree is felled – the long aged products (buildings and furniture) are assumed to be carbon storing, but on average only 20% of each tree is converted into long aged products, with the remainder going into paper or burnt this upstream carbon needs to be attributed somewhere, and likely needs to be attributed to the long-lived products otherwise it is missing (forgive me if I have missed an attribution elsewhere).
Finally we know that forestry practices significantly increase the risks of fires and beetle attack in our forests, the emissions of these ‘natural disturbances’ far outstrip biogenic carbon storage, and some portion of these emissions should be attributed to forestry products, how much is an open question.