There are a tremendous number of variables in tree appraisal.  However, like antiques, condition is critical.  A hazardous tree can be an outright liablility.  So, it pays to take care of mature trees.  During construction projects, spending a few dollars and talking a little extra time can result in actual cash value.  However, effective tree protection practices are often the exception rather than the rule.  “Tree protection is one of the biggest boondoggles ever,” says Dennis Swartzell, marketing manager at Mountain States Wholesale Nursery in Las Vegas, Nevada.  For more than twenty years, Swartzell was arboretum director at the University of Nevada, Las Vegas, and watched the 337-acre facility grow from open park-like land to a bustling campus with facilities for 24,000 students.  In other words, the grounds were under constant construction, which often conflicted with the existing trees.

“No one thinks about tree protection, especially the contractor,” says Swartzell.  “At the completion of the projects everyone is shrugging their shoulders and pointing fingers.  The trees end up being the losers.”  In most urban areas, preserving mature landscape trees during renovations and upgrades is the primary concern.  However, new construction is also a large concern in suburban and even rural areas of the nation.  As cities sprawl over the countryside, countless trees are demolished to make way for housing tracts.  In many cases, with a little forethought, the homes in these developments could have an “instant” landscape feature that would add value and provide energy savings from day one. 

Whether you are looking at specimen trees in an existing landscape or in a new construction setting, most of the same rules apply.  Protecting trees is a process.  If you follow a few simple steps, you should successfully save your most prized specimens.  If you are not trained to work with trees, look into hiring a certified arborist or consulting arborist who specializes in tree protection.  Although the up-front cost may seem high, it will pay off handsomely in the long run.

First of all, you need to determine if a tree is worth saving in the first place.  Although this may seem obvious, trees with structural problems or are at the end of their life cycle may look fine to the untrained eye, but could easily become hazardous when subjected to the stresses of construction.

As a general rule, the younger the tree, the better chance that it will adapt to its new environment.  Some tree species also tolerate construction stresses better than others do.  If you are working with Ulmus spp. (elm), Populus (poplars and cottonwoods, but not aspens), Salix spp. (most species of willow), Platanus (sycamores) and Gleditsia and Robinia spp. (locust), chances are good that the tree will survive and thrive.  However, Fagus spp. (beech), Liriodendron tulipifera (yellow poplar, which is really not a poplar at all, but actually in the Magnolia family), Carya spp. (hickory), Betula spp. (birch), presents a greater challenge.  Oak trees can range from fairly hardy (white oaks) to susceptible to any damage (scarlet oak).  Most maples would prefer to remain undisturbed; the sugar maple is probably one of the most sensitive, while the silver maple can be the toughest (although many arborists would argue for any silver maples’ removal!).  In general, conifers should be well protected.

If you are working on a large site with many trees, the first thing you need to do is take an inventory.  Look for trees that are damaged or decayed, leaning, or show excessive insect or disease damage, and slate them from removal.  Trees that are removed should be cut down flush to the soil, and the stumps should be ground out with a stump cutter.  Using a backhoe or large equipment to rip trees out of the soil is not recommended, because the resulting soil compaction can impact the remaining trees.

Speaking of soil compaction, that is probably the biggest problem during construction activities.  Traffic from equipment or people can literally squeeze the life out of a soil.  The pore space, where life-giving air and water resides, vanishes when the soil is compacted.  Since this is where plant roots forage for nutrients, decline and death are sure to follow.

So, once you have determined which trees you want to keep, it’s essential that the soil beneath them be kept free of machinery, equipment and even foot traffic, if possible.  This also goes for solitary trees in existing landscapes that may be victims of building, remodeling or landscaping retrofits, such as patios or pools.