I generate a huge amount of mulch on-site thanks to the large stand of bigleaf maple trees that spread their branches over half of our backyard. I set up a wire mulch bin directly under the biggest tree:
Leaves fall directly into the bin, and in the fall/early winter, I remove some of the old ones to the garden beds to protect the soil, and add fresh leaves that I rake as they fall from the trees. During the year I turn them every so often. By springtime, when I’m really ready to apply to the garden, the leaves on the bottom have turned into a delicious, moist, fluffy, dark, mulch:
Applied directly onto the garden, it provides extra organic matter, helps retain moisture, and is generally awesome for the soil and the plants that live in it. Of course, it’s not enough. I do end up buying more throughout the season, and supplementing with grass clippings.
It does mean that on occasion I have to remove baby maple trees from the garden, but having an on-site source for large amounts of mulch is super-fantastic.