How long do leaves remain "green" for compost material after cutting a tree?

Question

I am planning to clear some trees from my property to make room for a garden. I would like to chip/shred the branches to be used as mulch and compost material. According to the Back to Eden gardening method, the wood chips that make the best mulch should be "arborist" chips that contain the leaves, needles, etc. to keep a good balance of green and brown materials.

If I want to chip the branches while they're still green, about how long after felling a tree do I have before the leaves turn from green material to brown? Is this on the order of days or weeks?

Answer 1

'Greens' and 'browns' in the context of composting are shorthand for categories of materials we can compost. It can be confusing because wood chips are 'browns', no matter how green they are!

'Browns' are any high-carbon organic material, like leaves, wood chips, cotton, cardboard, paper, or straw. These things are usually brown but they don't need to be, like your green tree branches.

'Greens' are pretty much anything else you compost and bring nitrogen and other nutrients. They are things like eggshells, coffee grounds, kitchen waste, cuttings from non-woody plants.

You can chip your branches when it is convenient for you- they will add 'brown' matter to the compost no matter when you do it.

Answer 2

Arborist wood chips are indeed the best mulch that you use in your garden. B ut Back to Eden is really not correct when Dr. Paul states that:

It is important to understand that the leaves are a source of nitrogen and the branches are a source of carbon. This ratio creates an ideal mulch gardening material when the wood chips have composted.

The leaves, needles, etc. are additional food for plants, yes, but extremely fleeting and not at all the main reason for using arborist wood chips. Check out this free, peer-reviewed fact sheet for much more information.

Is the good Dr expecting that you'll be replacing the wood chips after the green stuff breaks down? I should hope not, because that's a lot of useless work. You should top-dress your wood chips with more wood chips annually, but not more than an inch, and that won't contain a heck of a lot of green matter.

Whether the leaves are green or brown when you put the chips down is irrelevant, as mulch does not follow the same rules as a compost heap. Regardless of color, they'll break down naturally within a few weeks. I've used wood chips for about 20 years now, and have never worried about fertilizing my chips. And I've had very nice gardens, even on horrible clay.