A bit of careful inspection could save a large tree from falling and causing damage to nearby structures. Oddly enough, there’s usually little connection between tree health and its likelihood of falling.
Don’t conclude that a tree won’t fall just because it’s growing straight, its leaves are green and its canopy is full. If the tree is structurally unsound, it’s more likely to fall sooner or later. One thing’s for certain; the larger the tree, the more likely it is to be a hazard to nearby structures.
Here are six simple tree structure inspections you should conduct once or twice a year:
1. Look for the “leaner”. They’re the trees that have recently moved from the vertical position and present a serious condition that requires prompt action. Leaners are simply in the process of falling and could go all the way at any time. Leaners usually result from substantially reduced anchorage. Root loss activities include trenching (especially close to the trunk), changing the grade and compacting the soil. Note that lots of trees do not grow vertically, and unless the vertical axis of the tree has recently changed, it’s not a “leaner.”
2. Weak “V” multiple-trunked trees. Check the bottom of the “V” union of the trunks of large trees. Trunks with splits may separate in the next windstorm, especially if the split is already long. It’s a weak union if the stem bark ridge turns downward and inward (included bark). The narrower the union, the more likely one or both of the trunks will split. The multiple-trunked tree is probably OK if there’s a noticeable raised ridge in the union, and the stem bark ridge turns upward and outward. A heavy main branch with included bark is more likely to split if it’s growing horizontally. Early training and pruning of large trees can substantially reduce these physical conditions.
3. Weakly attached main branches. Check the larger branches where they attach to the trunk. If there’s a split, chances are that branch will have to be entirely removed. Trees with lots of branches originating from the same point on the trunk are weak, and are potential candidates for splits.
4. Decaying cavities. Check the trunk and main branches for large decay pockets or cavities that represent structural weaknesses. Failure potential is greater if cavities or decay occur at a point where loads are great, such as at the base of the trunk or where branches meet. If you clean out rot, be sure to not scrape healthy wood, and don’t seal a cavity.
5. Trunk and main branch cracks. If you find a crack, insert something narrow such as a skinny screwdriver. If the crack exceeds three inches it is likely to extend beyond the bark and into the wood. Deep cracks indicate a separation of the wood, which has weakened the structure.
6. Deadwood and hangers. Both will eventually fall. If dead branches and broken branches still attached to the tree are large, they should be removed.
If any of these conditions exist, contact a certified arborist or other tree expert by looking under “Tree” in the phone book yellow pages.
Marc Soares lives in Redding. He is a landscape consultant for already existing gardens. He’s also the leader of Indigo Brew, a jazz band. Upcoming dates include Feb. 22 and 23 at the Post Office Saloon, and March 2 at Redding’s Old City Hall. He is the director of the West Valley High School Band, and swim coach for the Anderson Aquagators and West Valley High School.
Soares is author of “100 Hikes In Yosemite National Park,” and “Snowshoe Routes of Northern California – The Mountaineers.” He can be reached at firstname.lastname@example.org.