Volcano mulching--how to kill a tree

Here at Lakeside we have a number of "healthy living" activities and organizations, from our now twice weekly locally grown farmers' market, to a no-smoking ordinance to recycling, to tree walks, bird watching events, early a.m. exercise class, posted activities for joggers in the park land at the south end, and health and wellness week. At one of the lectures sponsored by LESS (Lakeside Environment Something? Something?) I learned about the care and preservation of our trees, many of which are invasive, like the Norway Maple, some with Emerald Ash Borer, and many over 100 years old. It's there I first heard about "volcano mulching," or piling mulch so deep around a young tree, that you eventually kill it with your kindness and concern.

1. Don't fall into the trap of the dreaded "mulch volcano," especially with young trees.

You've probably seen mulch volcanoes on people's lawns. Folks build circular raised beds around their trees, then fill the raised beds with wood-chip mulch. The mulch gets steeper and steeper the closer it gets to the tree, which shoots out of the hole at the end like a lava eruption! In a typical mulch volcano, the mulch may be 2" high at the perimeter and 6" high up close to the trunk.

There are several problems with mulch volcanoes:
Water runs off the sides of the mulch volcano and away from a young tree's base (which is where all its roots are, for now), thus depriving it of water.

6" of mulch is too deep. Much water that would otherwise reach the tree's roots gets trapped in the mulch.

Excessive tree mulching invites rodent pests and diseases.
Excessive tree mulching can even suffocate roots.

2. Don't mound up dirt or mulch around the trunks of trees.

Piling up mulch against tree trunks can cause harm to your trees: it invites diseases and rodent pests. If you are mulching around a tree, start tapering the height of the mulch down when you get to within about 1' of the trunk, leaving the base of the tree free of mulch. It would even be better to have to weed this 1' than to risk damage to your tree, wouldn't it? About landscaping

Every year there are more and more rules at Lakeside--most positive and for the good of the larger community; barking dogs; hours construction can take place; proper disposal of plastic, paper and metal; building codes for cottages; coverage of buildings on lots; number of parking places required for each cottage; no smoking; no alcohol; no parking on certain streets; quiet zones after 10 p.m.; and so on.

So I am very puzzled that if volcano mulching is known to be harmful to trees, why the Association can't explain that to its landscaping crew, because almost every young tree I see (usually a memoral plaque near-by) has heaps of mulch that will eventually cause the roots to girdle, or rodents to chew, or bark to rot. This would seem to be easier to control than calories, exercise or smoking.



Our speaker on tree care told us to think do-nut instead of volcano.

The rule is simple. Never let mulch around the base of a small tree touch the bark of the tree. The circle of mulch can be three to four inches deep, but in the middle of the circle the trunk is kept bare. The mulch layer should start about 6 inches from the trunk. We want doughnuts not mountains.

This is not new information. It has been general knowledge among reputable tree care professionals for 25 years. The tree care companies that make mulch mountains are just plain ignorant and apparently don’t spend much effort to learn the right methods for mulching small trees. Homeowners see these mulch mountains and figure if the professionals make mulch mountains, maybe I should do the same. The Yardner