By Jim McCausland, Sunset senior garden writer

Conventional compost piles digest and reduce weeds, grass, and leafy garden waste in just a few weeks—but what do you do with woody waste? Ned Conwell, who teaches composting techniques at Regenerative Design Institute in Bolinas, California, says “I put branches and anything thorny in a separate slow-roast pile in the corner, where it breaks down over a much longer period of time.”

You build such piles by throwing everything from rose canes to fruit-tree prunings into a heap in an unseen corner of the garden. At first the pile seems unreasonably high and airy, as though it will never break down. But as the months pass the pile settles much faster than you might have guessed, and the material on the bottom starts to rot even as you keep throwing new material on top. Small birds love the protection and concealment enough to build nests in these piles.

These are the easiest compost heaps ever, since it isn’t practical to layer and turn them. Just let nature do its work.

If you have woody waste but no room for a slow-roast pile, you can rent a shredder-chipper and grind everything up. Use the resulting material directly as organic mulch in shrub beds that you don't work with bare hands (thorns take a long time to break down), or compost it in the conventional way: it breaks down fairly quickly after it’s been ground up, layered with green matter, turned, and moistened.