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Planting Trees
For A Cooler Earth
In A Warmer Wyobraska
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Wyobraskans have never needed
much additional incentive to plant trees. Pictures,
paintings, and drawings of the region’s landscape
before European settlement show a predominantly
prairie landscape with only a few trees tucked away
in the ravines that scar the sides of and on top of
the ridges and buttes that give the region most of
its scenic landmarks. One of the first priorities
for European settlers was to plant trees to provide
a shelter from the winds which frequently swept
across the open prairies and to provide shade from
the region’s unrelenting summer sun.
Maintaining and replacing the
trees planted by those first settlers has become a
responsibility handed down to successive generations
of Wyobraskans. Each generation has added its own
set of criteria to the trees they plant in the
Wyobraska landscape. Those first generations
required trees that were fast growing and drought
tolerant—remember that modern drip irrigation
technology was not available them. With the first
windbreaks and shade trees established, homeowners
began selecting trees based more on their ornamental
qualities, like spring blooming, colorful fall
foliage, or a generally neat and refined
appearance. These remain the most common
motivations for planting trees in Wyobraska today
Now, however, an increasing
number of Wyobraskans are hearing that one of the
best solutions to global warming is to plant trees.
The advocates of tree planting as a solution to
global warming correctly point out that trees pull
carbon back out of the atmosphere and store it for
relatively long periods of time in their woody
tissues. Virtually no one on either side of the
global warming debate disagrees about the capacity
of trees to store carbon, so it has quickly become
an activity of choice for those who want to act on
this issue now and debate it later.
I have not always been an
advocate of planting trees anywhere and everywhere
in Wyobraska, and I personally think that it is
important that we retain open sunny areas in our
landscape where the grasses and wildflowers of the
region’s native landscape can retain their rightful
prominent place in our residential and public
landscapes. But it seems possible to me, to blend
the tree planting motivations of now multiple
generations of Wyobraskans into an approach to tree
planting that addresses global warming, that
provides human comfort in what remains a windy and
sunny region, and that still reflects the uniquely
dynamic and colorful grass and flower filled
character of the region’s native landscape.
Here are a few ideas on what
trees to plant and where to plant them in around our
homes and throughout our communities—specifically to
reduce carbon levels in the earth’s atmosphere.
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Where to plant “global
warming” trees?
There are several easy answers
to this question. Those who study sources of
atmospheric carbon point out that our homes tend to
be big sources of carbon in the atmosphere.
Generating electricity for use in powering, heating,
and cooling our homes is a major source of
atmospheric carbon. So one obvious location for
“global warming” trees is within 10 to 20 feet of
your home.
In Wyobraska this translates into some sort of
evergreen trees on the north side for wind
protection in the winter, shade trees on the south
side for cooling in the summer, and some combination
of shade and/or evergreen trees on the west for both
wind buffering and cooling.
This is a slight departure from traditional tree
placement in residential landscapes.
Traditional recommendations have been to plant trees
slightly farther away from homes and other
structures, but the farther away from the home, the
less trees are able to reduce the homes “carbon
footprint”—especially in an urban residential
setting.
Another easy answer as to where to plant, is to use
trees, rather than lawn as the default landscape.
Almost every residential landscape has those odd
unused spaces that are rarely used for recreational
play or any other function requiring turf grass, yet
which are unthinkingly planted to grass—then watered
and mowed indefinitely.
The spaces between homes in residential
neighborhoods are a good example. These spaces
could just as easily be planted with trees—reducing
landscape water use, reducing weekly homeowner
maintenance work, and reducing atmospheric carbon.
Talk about a win, win, win situation.
In public and residential
landscapes, the traditional approach to planting
landscape trees has been to plant single specimens,
spaced so that each trees remains an individual tree
in the landscape as it matures. Meanwhile the space
beneath the trees is planted to some version of
intensely maintained turfgrass—which both stresses
the trees and stores almost no carbon. In nature,
trees grow in forests or groves. Leaves and small
twigs fall to the forest floor and form, over time,
a rich, permanently mulched soil. Planting groves
of trees, rather than individual specimens, will
mean healthier, longer lived trees, and it will mean
less landscape maintenance work for the homeowner.
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What “global warming” trees
to plant?
Because global climate change
may mean significantly lower annual rainfall for
Wyobraska, I would suggest that trees planted in
Wyobraska specifically for the purpose of reducing
atmospheric carbon be among the toughest and most
adaptable trees. Trees planted near homes will
likely have adequate supplemental irrigation
available even under the strictest water
conservation scenario, but groves of trees planted
at the edges of residential landscapes, in parks and
other public spaces, should probably be able to
survive prolonged periods of drought without
supplemental irrigation.
Following is my list of
suggested “global warming trees” for Wyobraska:
Evergreen Trees
Ponderosa Pine
Rocky Mountain
Juniper
Pinion Pine
Limber Pine
Austrian Pine
Scotch Pine
Deciduous Trees
Bur Oak
Gambels Oak
Hackberry
Western Cottonwood
American Linden
Hybrid Elms
Northern Catalpa
Kentucky Coffeetree
Ohio Buckeye
Gray Dogwood
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