Some threats to trees are manmade. As such, they can be avoided. Here are some problems and their solutions.

1. Improper planting. “Be able to identify where the root flare is when you purchase a tree,” says educator and consultant Robert Wells, founder and former owner of Robert Wells Tree & Landscape Inc., Princeton, New Jersey. “We see it a lot, trunks buried four to eight inches deep. If you put a tree into the landscape like that it’s immediately under stress.” Root-girdling is another result of improper planting, arranging roots around in a circle in the hole. As the roots grow in diameter, they start to constrict the trunk of the tree, and can pinch a tree off at the base, making if vulnerable to windstorms.

2. Too much mulch. A little mulch is a good thing; it returns organic matter to the soil and retains moisture. “Overmulching is the number one mistake I see landscape people making,” says arborist Bill Joseph. “Water can’t get to the root system.” Especially avoid “volcano mulching,” piling matter several inches high against a tree’s trunk. This invites pests, fungus and rot. It should never be more than 2 inches thick and should never touch the trunk.

3. Topping and improper pruning. The uppermost part of a tree should never be chopped off. It sends it into decline. So can imprudent pruning. Inexpensive courses in pruning best practices can be found on the ISA website.

4. Mechanical damage. It’s easy to prevent this one. All you need to do is instruct your crews to be careful not to hit tree trunks with mowers or strip bark with string trimmers.