Thus the key problem is how to meet varied economic objectives besides its fuel application of fuelforest on the basis of holding its soil conservation function.
因此，薪炭林在发挥水土保持功能的基础上，如何达到兼有薪用的多种经济目的是关键。
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They include: legislation on fuel efficiency for cars by 2011 and new building efficiency by 2012, getting 20% of energy from renewable sources by 2020; and expanding forest cover.
If the forest gets dry enough, air can get into the vessels that carry water through a tree - kind of like an air bubble in a fuel line - and a tree dies.