Construction projects can be disastrous for existing trees on the building site. A tragedy we see often is when home builders attempt to save existing trees, only to have them die because of construction-related damage and stress.
Shade trees add to the value of home sites, so it’s a terrific idea to preserve them so that the new home will have “instant shade”. In rural areas it’s common for new homes to be built on wooded sites; home builders clear room enough for the building, driveway and lawns but leave the nicest trees. This adds inconvenience and expense to the construction process, and may even increase the cost of the building site, so it’s a double loss if the remaining trees don’t survive.
If you plan to build adjacent to existing trees, it’s important to protect the trees at every step of your project. This starts with careful planning. As nice as it might be to have large shade trees in your yard from the beginning, you have to be realistic about which trees can be easily saved. Some trees are more forgiving than others about disturbance in their root zones. Paving, trenching, digging and compaction near trees is likely to kill then sooner or later; it’s more expensive to remove them once your project is finished.
Trees have feeder roots well beyond their “drip line”; the reach of their longest limbs. They also have “buttress roots” closer to the trunk. These are essential pipelines for food and water, and also keep the tree from falling over. Digging, trenching, machinery traffic, or changing the root depth by cutting away or adding to the soil in the root zone is likely to kill the tree sooner or later.
Careless operation of power equipment can tear low-hanging limbs and scrape bark off the trunks of trees. Tree bark is essential for carrying food and water up the tree and protecting it from insects and disease.
There are simple steps you can take to preserve existing trees during construction. Communication with everyone involved, at every step of the process, is key. Simply staking out as large a circle as possible around the tree with construction fence or caution tape sends a clear message. You should also prune or “limb up” low-hanging branches to provide clearance. When planning the location of trenches or pavement, give the trees a wide berth.
If roots are cut during digging, you should make a clean cut, removing torn or broken sections. Clean pruning cuts of roots or branches will heal faster, sealing the tree against pests and disease.
A common mistake is adding or removing soil in the tree root zone, Trees breathe through their roots, so adding even a few inches of new dirt around them can smother them. Cutting away soil is worse; it damages delicate feeder roots and removes nutrient-rich topsoil.
Does your site plan or blueprint show the locations of nearby trees you want to preserve? If not, it helps to measure and draw them onto your plan so that you can adjust the locations of your foundations, pavement, utility and drain lines. It may take some vigilance on your part to keep contractors away from vulnerable tree roots; it helps to plan a route for buried utilities, concrete trucks and other hazards and then fence off where they shouldn’t tread.
One other point to remember: trees in woods are a community. They protect each other from sun, wind and weather. Some say they even communicate with each other (more on this in a future column). In any case, drastic thinning of less desirable trees can be very stressful (and often fatal) to the trees that remain, which are then very likely to fail or fall over. The best tree in an open area is one that has grown by itself for a long time, preferably because it started there from seed. The odds of survival for forest trees, after losing their brothers and sisters and enduring the stress and hazards of new home construction, are 50/50 at best, and then only if you take special care to protect them from trauma.
Steve Boehme is a landscape designer/installer specializing in landscape “makeovers”. “Let’s Grow” is published weekly; column archives are on the “Garden Advice” page at www.goodseedfarm.com. For more information is available at www.goodseedfarm.com or call GoodSeed Farm Landscapes at (937) 587-7021.