Twenty years ago when I bought my farm I made a snap decision to
clear some woods near the house, all the way back to the stone
wall. Out came the chainsaw and trees started crashing down.
I never did finish "neatening up" that section of the fence
line. And it was only later that I realized that I had turned the
only sizable northern red oak on the entire 40-acre woodlot into
firewood. As a guy who prizes forest diversity, I was chagrined. No
help for it. Except… a few years later I noticed some healthy
sprouts from that oak stump. I left them alone. Now the three
biggest are six to eight inches in diameter and some forty feet
Stump sprouting is kind of like an insurance policy for many
trees, even those that take other steps to ensure their species'
survival, such as producing prodigious quantities of seed. Most
temperate hardwoods have this ability, though some, like oak and
beech, are better at it than others. Most conifers do not, an
exception being the redwood, which is a champion sprouter.
Sprouts are generated by different mechanisms, depending on the
species, explained Kevin Smith, a plant physiologist with the U.S.
Forest Service's Northern Research Station. Sometimes sprouts are
produced by dormant buds that remain immersed in the bark until the
tree is stressed or injured and then are prompted to break
dormancy. Other sprouts are produced from pads of juvenile callus
formed from mature living wood cells.
"It's quite a trick, but some species do it readily," Smith
The big advantage to stump sprouting is that the sprouts get
access to the root system of the original tree and its accumulated
energy reserves. (This is also true for trees that send sprouts up
from their roots.) It's like starting life with a huge trust fund.
It's no guarantee of success, but it gives you a head start.
There seems to be something of a "use it or lose it" aspect to
this ability, however. In a 2001 study on tree sprouting published
in The Botanical Review, the Arnold Arboretum's Peter Del Tredici
noted that hardwoods will sprout "vigorously" from stumps between
about two to six inches in size and that most will continue to do
so from stumps up to 10 or 12 inches in size, but in lower
percentages. Beyond 10 to 12 inches, the "number of non-oak species
that are capable of successful sprouting drops off precipitously,"
Del Tredici wrote. The reasons for this size limit are poorly
Humans have long exploited hardwoods' sprouting tendency. In a
practice called "coppicing," young trees are allowed to regrow from
stumps and harvested every few years. Historically - especially in
Europe where forests can be scarce - coppices provided wood for a
wide variety of uses, from firewood to fencing. Some stumps, called
"stools," have been harvested for centuries.
Coppicing is still practiced, and is having something of a
resurgence among permaculture devotees, but not to the extent that
it once was.
Even if a tree produces copious numbers of sprouts, it's no
guarantee that they'll all live. Some trees apparently "self thin"
their sprout production. And in many cases sprouts die because they
are infected by rot from the stump itself.
While many foresters profess not to like sprout clumps, Smith
notes that at least one study shows that in New England, a lot of
merchantable hardwood is produced by them. Beyond that, studies
show that stump sprouting, in allowing rapid regrowth of trees,
preserves the forest microclimate, inhibits erosion, and conserves
"Part of the strength of our forests," said Smith, is that most
hardwoods have both the ability to sprout, perpetuating the
original tree, and to produce seeds, which allows for a stirring of
the gene pool. The combination, he said, "contributes to
Joe Rankin is a forestry writer, beekeeper,
orchardist and market gardener who lives in central Maine. The
illustration for this column was drawn by Adelaide Tyrol. The
Outside Story is assigned and edited by Northern Woodlands magazine
and sponsored by the Wellborn Ecology Fund of New Hampshire
Charitable Foundation: firstname.lastname@example.org