Cooperative Living October 2023 - 10

BRANCHING OUT
Bald Cypress
by Steve Carroll, Contributing Columnist
Our region's only deciduous conifer
B
ald cypress is a truly unusual tree. It's a
conifer - therefore related to pines and
spruces - but it drops all its leaves each
fall. It epitomizes the swamps of the southeast
U.S., yet it readily grows as far north as New
England. It prefers rich, moist-to-wet, acidic
soil, yet can be grown as a lawn or street tree in
dry, well-drained soil. Th is is a remarkable native
deserving our admiration!
Under favorable conditions, bald cypress
(Taxodium distichum) can grow 70-to-100 feet
tall or more with a 3-to-5-foot diameter. It is also
the longest-lived tree in the eastern U.S.; many
specimens surpass 1,000 years old, with at least
one North Carolina tree exceeding 2,600 years.
Bald cypress's soft , fl at needles are one-half
to three-quarters inches long and grow in two
ranks along small branches. Leaves become darker
green through summer, then contribute to our fall
display by turning an attractive rusty red-brown.
In winter - when trees are " bald " - the fi brous,
reddish-brown bark is evident.
Autumn-leaf drops by conifers occurs in
3
1. Bald cypress with knees in
Congaree National Park, S.C.
2. The soft, green foliage of
bald cypress.
relatively few species, including larches and
dawn redwood. Th is begs the question " Why? "
Losing leaves in the fall requires their total
replacement the following spring, an immense
energy investment. On the other hand, shedding leaves frees
trees from maintaining them through the winter. Being leaffree
also decreases water loss through transpiration. Other
biochemical and physiological factors aff ect this " decision, "
but in most conifers, the balance has tipped toward retaining
leaves. Fortunately, we have these fascinating exceptions that
enrich our world.
Like most conifers, bald cypress produces male and female
3. Bald cypress needles
showing fall color.
4. Large bald cypress trees
showing fall color.
4
several knees emerged in the dark, moist confi nes of our
house's dirt crawl space, requiring me to navigate through
this mini-maze when it was necessary to go down there -
which I don't mind admitting was as infrequently as I could
get away with!
Bald cypress produces strong, light, rot-resistant wood
cones on the same tree. Male pollen-bearing cones are small
and short-lived, falling off aft er the dispersal of their pollen
by wind. Fertilized female cones are green, globular and up to
an inch in diameter; these turn purple-brown before releasing
seeds in the fall.
One of this tree's most unusual features is the development
of " knees " that grow upward from its roots, especially in
wet soil. At least two hypotheses attempt to explain these.
One argues that they contribute to gas exchange, since water
and wet soil hold less oxygen than the atmosphere. Another
8 * Cooperative Living * October 2023
that has been used to make barrels, railroad ties, shingles,
greenhouse benches and other products where rotting might
be a problem. It also helps feed our wildlife, with its seeds
consumed by turkeys, evening grosbeaks, waterfowl, squirrels,
and other birds and mammals.
Bald cypress is a tall, long-lived tree with four-season
interest. It's not suitable for all properties, but if you have the
right spot, consider planting this unique and beautiful tree.
Steve Carroll is a botanist and ecologist who speaks and writes
about trees, gardening and the world of plants. He is the co-author
of " Ecology for Gardeners, " published by Timber Press.
co-opliving.com
*
Bald cypress is
the longest-lived
tree in the
eastern U.S.
suggests that knees provide additional structural support
in water and wet soil.
I was fortunate to have a good-sized tree in the front
yard of a previous home. In this full-sun setting the tree
produced just a single, small knee, easily kept in check
by the lawnmower. But like most trees, bald cypress roots
extend well beyond the reach of its canopy. As a result,
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PHOTO BY SHAWN TAYLOR VIA FLICKR
PHOTO BY DAVEYNIN VIA FLICKR
PHOTO BY MALCOLM MANNERS VIA FLICKR
PHOTO BY KATJA SCHULZ VIA FLICKR
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Cooperative Living October 2023

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