Going through David Holmgren's version of the Permaculture Design Principles, here's #5.
Use and Value Renewable Resources and Services
More sun comes tomorrow (or at least more solar energy), as do the wind and tides. On a longer timescale the fruit and nut trees produce a harvest each year and the alfalfa covers the back field. The trees provide shade each summer, the flowers give pollen to the bees, and the hedgerow is a windbreak.
The first list, energy and food, represents resources that are consumed and will be replenished. The second list represents intrinsics that can be thought of as renewable services since use of the service is non-consuming. Both aspects should be priorities, as we try to eek out every useful bit in our designs.
Holmgren takes an interesting approach to the consumables, asking "what is the half-life of the product?" I'm not sure I agree with this, since his example is the lifespan of paper (a few years) compared to the trees that produce it (decades), and suggests that the trees be put to more lasting use (we'll get to slow solutions in a later principle). I think a better method would be to appropriately value the replacement cost/time for the underlying resources into how we value the products. By being more plugged into the true costs of the things we use everyday, we can make better choices about how we consume.
Sticking with trees, the rule of thumb is that you can sustainably harvest about a cord per acre. Here's what one paper industry site says you can get from a cord of wood:
- 12 dining room table sets (seating eight)
- 30 rocking chairs
- 250 copies of the Sunday New York Times
- 942 one-pound books
- 1,000 to 2,000 pounds of paper (depending on grade)
- 1,200 copies of National Geographic magazine
- 2,700 copies of an average (36 page) daily newspaper
- 4,000 one-gallon milk containers
- 61,370 standard (#10) envelopes
- 89,870 sheets of letterhead bond paper
- 460,000 personal checks
- 4,384,000 postage stamps
- 7,500,000 toothpicks
I'm thinking that this means that a reasonable size woodlot can sustainbly produce a range of products in differing amounts that balance both the productivity of the forest with the needs of the community.
Pretty picture of the principle at permacultureprinciples.com