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Tree Stump Troubles

Turn a problem into an opportunity: Make that old stumpy thing a food factory or ornamental showplace!
Q. Dear Mike: I have a tree stump in my yard that is about four feet high and approximately ten feet around. It couldn't be cut any lower because the tree grew around old fence posts and the chain saw blades were getting ruined.  Is there any way to speed up the rotting process?  Thank you,
                          ---Denise (who apparently doesn't live anywhere)

Mike: Do you know of a way to get rid of tree stumps?  I have two large ones from pine trees that were snapped off in a windstorm last fall. They are about 4-5 feet across, so digging them out is not really possible (and I can't fit a stump grinder in my car!).
I would like to plant something in their space, and so would like to get rid of the stumps sooner rather than later. P.S.  I love your show!! Thank you,
                          ---Barbara in Wynnewood, PA

A. First, forget about using any 'stump killer', 'stump remover', 'stump decayer', 'stump dissolver' type products. University of California researchers tested them back in 1994 and found that they simply did not work.   

If you can get a backhoe in there, it's often worth it to pay someone to pull the thing (or things) out of the ground for you. It'll cost some money and a mess, but you get to go home REAL early. Trees that didn't eat fences can then be ground up by big machines (that no, don't fit in cars). The Fence Post Monster (a new character for Sesame Street? "Umm! Fence posts! Good!!!") should be rolled into a gully or similar area to rot.

The fastest way to accelerate the demise of a stump in the ground is to drill holes or make chainsaw crosscuts in the top, keep it really wet and rot the wood. But you can also leave that stump in the ground and make it useful. If it's the right height, sand and stain the top to make a great outdoor table. Or just put potted plants on top of the stump—or drill a big hole in the center, fill it with high quality potting soil and use the stump like it was a big pot; this looks way cool and greatly accelerates the eventual decomposition of the stump.
Or cut the thing off as close to the ground as possible, and build a raised bed over top of it. Make a frame out of naturally rot-resistant wood, field stone or a composite lumber like Trex (, and fill it with good soil. Plant shallow-rooted flowers and veggies to start, and then after a few years, put whatever you want in there: Tomatoes & basil, flowers and eggplant; canna lilies and Uncle Louie…This really accelerates the decomposition of the stump below, quickly turning it into food for your plants above.    

But your most interesting option is to turn that stump into a mushroom factory. One source for the 'seed' (wooden dowels inoculated with gourmet or medicinal mushroom spores that you insert into holes drilled into the stump) is, where my good and personal friend Paul Stamets sells all kinda cool mushroom-growing supplies thru his company "Fungi Perfecti". (Mention my name and get a 20% surcharge!)

This will achieve two things: 1): You'll get really tasty or medicinally useful mushrooms to eat. And 2): The growing mushrooms will also greatly accelerate the decay of the stump! The mycelium, the living body of fungus, seeks out wood—the food that fuels it's growth. Spores germinate and form branching mycelia networks which will eventually form full-sized mushrooms once enough of the wood has been digested. The mycelium's job is to cause wood to decay, decompose and just plain go away real fast.

When we discussed this wonderful tactic on the show a while back, Paul said the birch tree stump identified by a listener would grow lots of great mushrooms, including Oyster, reishi, enoki, shiitake, and the birch polypores (AKA the "Ice man Fungus"; Fomes fomentarius and Piptoporus betulinus). And he added that King Oyster (Pleurotuseryngii) and Garden Giant (Stropharia rugoso-annulata) would grow on birch chips.

I called him for an update, but he's attending the World Mushroom Biology Conference in China—so I instead spoke with Jim Gouin, are search assistant at Fungi Perfecti who specializes in tree stump colonization. Jim explains that the best trees for "plug spawn inoculation" are hardwoods like oak, ash, birch, alder and maple. Some softwoods, like Douglas firs and Eastern and Western hemlocks, work okay for certain mushroom species, he adds—and delicious shitakes grow very well on eucalyptus tree stumps!

The ideal time frame is two weeks to six months after cutting. You should give it about two weeks to kind of 'cool down'; but don't wait forever, because local fungi will start to move in after about six months. And you have to be patient; mushrooms don't grow nearly as fast outdoors as they do in controlled conditions, like with kits—most tree stump mushrooms will take a good year or two to get established. If you're in a hurry, Jim says to go with an oyster mushroom; they're the fastest growers. (He adds that they carry a very aggressive strain of classic white oyster mushroom.)

Obviously, stumps in shade are preferred. But it can be done in the sun, he adds—just coat the stump with a food grade wax ('bees' or 'cheese'; not petroleum-based) to prevent dehydration. This will also prevent contamination by 'foreign' (actually local) spores—which is why Jim recommends the wax coating for shady stumps too.

This won't work well with trees that regrow from cut stumps, like cottonwood and locust. And true pines are problematic because of their high 'pitch' content. Mushrooms do occur on pines in the wild—fungibreak down all fallen wood—but nobody wants to sell you the 'seed' because the useful mushrooms that do this are similar in appearance to species that are unsafe to eat. Check out FungiPerfecti's site or catalog for more details.