Eco-Friendly Living: How to Protect Trees During Construction

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A 125- year-old white oak in Hope, Rhode Island, before construction began on the neighboring house.
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The same oak one year later after developers were forced to add 3 feet of fill soil over its roots to obtain a septic permit.

An experienced arborist shares a list of tips on how to protect trees during construction season.

Here are pointers from Dennis Brown, consulting arborist with Urban Forestry Resources in Austin, Texas, on how to protect trees during construction season:

• Make a plan to minimize construction activities near trees.
Trees don’t heal like people do. Injuries might grow over,
but they will never really go away. It might be too late,
once you start to notice a tree is being affected. and most
won’t show signs until five to seven years down the road.

• If you have to do some digging in a tree’s root zone, try
to consolidate the work. Plan a route that can be used for
as many purposes as possible such as utilities, foundations
and trenches. Also try to minimize any changes in
the land’s drainage
. Too much or too little water
in the soil can kill a tree.
Don’t use any more
than 4 inches of fill soil over a tree’s root zone

. Adding extra soil interferes with a tree s ability to
exchange gases in its feeder roots. Carbon dioxide will
build up, literally suffocating the tree to death.

• Suffocation can also happen if the soil in the tree’s root
zone is compacted by heavy machinery. Just three or
four trips over the root zone by a bulldozer can cause
lasting damage to a tree
. If heavy equipment must
be driven over the root zone, mitigate damage by putting
down a wood chip mulch in the area. The mulch will absorb
much of the pressure without compacting the soil.
• Trees are
bigger than you think. Brown says a good rule of thumb for
estimating the spread of a tree’s root system (vital for
tree health) is to figure the root system stem extends out
from the trunk three times the height of the tree.
• Don’t
compensate for stressing the tree by adding fertilizer.
Trees seldom benefit from fertilizers even when they are
not stressed.

The best way to ensure your trees’ health during
construction is to employ a consulting arborist from the
start, according to Brown.