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<br />06885 Plcvellting Construction Damage to Trees
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<br />Al:l"icultural publication ('..6885 -- Reviewed May 15, 1996
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<br />Preventing Construction Damage to Trees
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<br />Dennis S. Schrock
<br />Department of Horticulture, University of Missouri -Columbia
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<br />Trees are a valuable asset in home landscapes. Their shade makes summer living more pleasant and can significantly reduce air
<br />conditioning costs. In \\'inter, they shield against wind and snow, reducing heating costs. L~aves act as ,air cl~aners, filtering
<br />dust and removingairbome. pollutants. Trees shelter wildlife, slow rainfall runoff, mume nOise and provide privacy. But perhaps
<br />the main reason people value trees highly is simply the beauty and grace they add to a community.
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<br />Because it takes many years for a tree to grow to maturity, wooded building sites command premium prices. All too
<br />frequently, however, the trees that make the site attractive are damaged during constru~tion ~~ees may decline and di~ soon
<br />after construction work is finished, The homeowner then faces the cost of tree removal m additiOn to the expense and tune
<br />needed to grow replacement trees.
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<br />Trees around older, established homes suffer from construction damage, too. Remodeling projects, sidewalk replacement,
<br />landscaping projects or utility work may cause injury to trees.
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<br />Types of construction damage
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<br />Damage to trees occurs directly from physical wounding or indirectly through change of environment around the tree.
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<br />Physical wounds
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<br />Careless movement of construction equipment causes wounds to tree trunks and root collars, the area of the tree at ground
<br />line where the roots begin to spread out. A healthy tree is capable of sealing off small wounds, localizing injUl)'. However,
<br />large wounds and those on stressed trees will not I1'adily seal off, allowing decay to begin.
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<br />Improper pruning to create clearance for construction equipment and tree removal techniques are other sources of physical
<br />injury to branches and trunks. As trees are removed fOf placement of a new building or driveway, they may scrape bark off
<br />trunks or break branches of trees that are to be saved. These wOlmds serve as entry points for diseases. Improper pruning
<br />leaves bnu'1ch stl.lbs that die and begin to decay. Make dean ct.-is with a sharp pnll1mg saw just outside the swollen branch
<br />collar.
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<br />Below ground, root damage is common from excavation and grade changes. Roots may be tom by improper excavation;
<br />opening wounds for disease organisms to enter. Fine, absorbing roots are lost by topsoil removal, putting the tree under stress
<br />Structural support is lost by trenching too close to major roots, creating a potential hazard. Bruising or crushing of roots by
<br />heavy equipment may not be apparent from above ground
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<br />Environmental cbanges
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<br />Soil com~tion is a serious problem onmany ~nst.rlict~o1;1 sites. Even when care is taken to avoid trunk and branch ~jury
<br />from ~Ul~ment, tr~ may be damag~ ~ eqUlpmerrt cJ:iVl~~ over root systems. The weight of the equipment compacts soil,
<br />reducmg au: sp~ m the root, Z<?ne, Lnmted oxygen avmlabllity to roots is also a problem when soil is stockpiled at the base of
<br />trees or paVIng IS put over eXlstmg roots.
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<br />Excessive thinning o~tree stan~ or removal ofunderbrnsh ca~s increased eXJXlsure to sun, wind and heat. Sunscaldmay
<br />develop on trees preVIously acclImated to shade. Increased wmd and heat exposure in.creases moisture stress.
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