Magazine article Sunset

Tree-Friendly Remodeling

Magazine article Sunset

Tree-Friendly Remodeling

Article excerpt


A guide to protecting valuable trees from construction damage

During a remodel, bad things can and often do happen to trees. Among the mishaps we've observed recently in neighborhoods around the West: A lovely, large Japanese maple, dug up during the heat of summer, left for a month atop the soil with its rootball exposed, then planted just a few feet from a new foundation. Young oaks, also dug up during summer, replanted next to a sidewalk; they died by fall. The tops of tall liquidambars lopped off to make way for an expanded roof line. Magnolia branches, broken by trucks, left hanging from stubs. And root zones cut in half to dig basements or trenches for computer cables.

Such damage is no surprise: When a 1950s ranch house is razed and replaced with a mini-mansion that fills much of a suburban lot, or a house is expanded outward, trees are often in the way. Designing a house addition to nudge or hug a large tree is not the answer; this solution does not allow for the tree's future growth, or for its movement during strong winds.

The time to protect mature trees on your property-if you decide to save them-is during the planning stage, before construction starts. Otherwise, you could end up paying many thousands of dollars to replace trees that are injured or killed.

There are a number of steps you can take before and during a remodel to protect your trees. Following them will pay off in the long run; indeed, trees are your landscape's most valuable assets-adding beauty and cooling shade around your house.

Crucial tree questions: save, relocate, or remove?

Before finalizing house expansion plans that may involve areas near established trees, consult an arborist certified by the International Society of Arboriculture (ISA). The arborist can evaluate the tree's health, age, present and future size, and any hazards it may pose. If the tree is healthy and in a strategic location such as a front yard, saving it may be worth the effort. If the tree is in the way of proposed construction, ask whether it should be removed, or, if it's young and healthy, if it can be moved. Also ask the arborist how far any solid paving should be from the tree's trunk to avoid suffocating the roots.

For a large, established tree such as an oak or redwood that will remain in its present location, avoid building within its root zone. "If you stay outside the canopy, we can almost assure the tree's survival," says arborist Jim Clark of HortScience in Pleasanton, California. As a guideline, allow at least 1 foot of space between the trunk and the structure for every inch of trunk diameter measured at 54 inches above soil level. To further protect roots, learn where any new underground lines will go, and if possible, reroute them away from trees. If it's not possible for contractors to work outside the root zone, up to one-third of a healthy tree's roots can be removed without severely harming the tree.

If you decide to remove a big tree, make sure you are allowed to. Without prior approval, some communities prohibit the removal of trees whose trunk caliper (diameter) is more than a certain number of inches.

Before breaking ground

It's a good idea to have the arborist consult with your contractor to find out exactly where the construction will take place and how to coordinate the building process with the tree's preservation. …

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