ForesterBlog.com
I don't envy those whose job it is to conduct timber inventories and calculate annual allowable cuts on large tracts of land, such as a Forest District or Region. There are so many variables to consider on the amount of sustainable cut a land base can bear.
For starters, you need accurate areas of all your forest cover polygons. You need to take out non-productive areas (e.g.: rock, brush), roads, water bodies, private land, etc. You need to consider the effects of forest health issues, such as mountain pine beetle and hemlock looper. One large outbreak could throw everything off. And even if all that data is accurate, you still need to estimate how much the trees are growing every year, and what is being cut. I have no doubt there are sophisticated models and equations to do this, but how accurate can they really be?
If the calculations are not accurate, more timber could be annually harvested than is sustainable. At some point there will be a falldown, and mills that depend on a certain amount of timber won't be able to find it. Conversely, if less timber is cut every year than is sustainable, this could lower economic productivity and reduce the number of potential jobs and revenues that could have been achieved. The problem is that it takes time to find out if you are over or under, and by then the impacts are being felt.
Timber inventories are especially critical in the central Interior of BC where there have been massive losses to pine stands from mountain pine beetle. There will no doubt be lower annual cuts coming in those areas, but is there an accurate current inventory available?
The article linked to at the bottom of this post discusses this issue. No doubt there is more effort required by the government to calculate our forest inventories.
A third of the government’s inventory of timber lands is at least 17 years out of date, the Ministry of Forests confirms. That makes it impossible to accurately establish the so-called falldown – the point at which mills in the B.C. Interior start to run out of logs after processing today’s pine-beetle-killed timber.
But the government is expecting a precipitous drop in timber supply in the Interior, according to Ministry of Forests data dated Dec. 31. The “mid-term timber supply” data shows the volume of trees to be harvested dropping by roughly a third over the next two decades.
To read the full article, click below:
http://www.theglobeandmail.com/news/national/british-columbia/bc-politics/timber-inventory-a-guessing-game-critics-charge/article2343616/
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1 comment:
Allowable annual cuts are based on data and analysis but they are not calculated. AACs are based on professional judgement.
But I agree about your comments on the inventory
another RPF
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