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Old Trees and Storms:
A Dangerous Combination

'Tis the season: wind and rain storms, combined with big, sickly trees, are creating disastrous results. During the downpour a couple of weeks ago, a 40 year-old silver maple tree, with a 40-inch diameter trunk, came crashing down on a pedestrian in Sacramento's leafy Land Park area, critically injuring him.

Unfortunately, the first sign of a tree's illness sometimes is such an occurrence. It's only after the tree has been downed in a storm that the cause becomes evident; in this case, it was heart rot, a fungal disease that causes the wood in the center or trunks and limbs to decay. As the University of California publication, "Pests of Landscape Trees and Shrubs" points out, this decay makes trees hazardous because the trunks and limbs become unable to support their own weight and can tumble, especially when stressed by wind or heavy rain.

Despite the lack of warnings in this case, there are signs of tree sickness that homeowners should look for to avert such a disaster in their own yard. A typical sign of heart rot is the presence of fungal growths, called conks, usually found around wounded bark on the trunk and limbs of aging trees. These fleshy, mushroom-shaped bodies find a welcome home in these vulnerable areas, usually caused by poor pruning or mechanical injuries from lawn mowers and weed whackers. Other signs of a sickly tree include cracks and cavities along the tree trunk; fresh soil fissures after a windstorm, where roots may be heaving; and, the presence of non-productive limbs during the growing season.

Keep your trees in good health with annual applications of fertilizer. Cut out dead or diseased limbs, and make the pruning cuts properly. Don't remove a limb flush with the trunk; keep your cuts an inch or so away from the branch collar, so the tree can heal itself more readily. Make limb cuts at an angle so that rainwater will drain off. Wound dressings are not recommended; research shows that they do not hasten wound closure or prevent decay.

Probably the best piece of insurance for homeowners who are the proud possessors of these aging, stately beauties that may unexpectedly come crashing onto a house, driveway or sidewalk: have your trees inspected by a professional arborist, at least once every few years.

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