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By Larry A. Sagers Regional Horticulturist Utah State University Extension Thanksgiving Point
For more information on protecting your trees from storm damage read my column in next Fridays Deseret Morning News.
Getting caught with your plants down is more than embarrassing. In fact, it is sometimes dangerous both for you and especially for your plants. The recent early season snowstorms brought havoc and consternation to some gardeners and many gardens. Broken branches, bent trees, sagging limbs and damaged structures are just a few of the problems from recent snowstorms.
Why is the problem so bad this season? As we have done so many times previously, we blame the plant problem on the weather.
Leaf drop on trees is an active growth process. Healthy trees from most species form an abscission layer of harden cells between the twig and the leaves. This blocks the flow of nutrients and water to the leaves and they stop manufacturing chlorophyll, which is the green component of the leaf.
Once the plant no longer manufactures chlorophyll, the natural orange, red, yellow and purple pigments are no longer masked and they start to show through. The brittle abscission layer then breaks off in the wind.
The problem this season is that the temperature remained very warm this fall. Many species of trees never formed the aforementioned abscission layer and the leaves were happily growing in summer-like temperatures when the snowstorms came.
Normal leave drop comes when temperatures cool gradually and consistently and the leaf abscission layers form. Because of unusually warm fall temperature, many species of trees had a full complement of leaves when winter struck.
The problem for some varieties is aggravated by an early frost. Once the leaves freeze, the abscission layer does not form and dead leaves hang on the branches and make them susceptible to breakage.
If the storm left you picking up branches, propping up limbs and tying up twigs, you are not alone. Like all good gardeners, the real trick is to learn how to prevent problems in the future.
Although it might be small consolation now, the real prevention is to plant trees that do not have the problems.
Some trees, including honey locust, black locust and others, have small leaves and are not going to catch much snow. Other trees including Ginkgo, most ash varieties, lindens and others drop the leaves early in the season so they are not going to pose a hazard.
The late dropping types include the English oaks, the sycamores and plane trees and the flowering pears. These keep their leaves late in the season and even through the winter. The breakage is intensified on the pears because their branches usually extend from the same point on the trunk and the wood is often very brittle.
Other trees with weak angles and brittle wood are the Siberian elm, the silver maple, cottonwoods, poplars and willows. These trees are among the most likely to go down after an early winter snowstorm.
For a listing of certified arborists in the state log onto http://www.isa-arbor.com/ and click onto the Utah link. These arborists have completed the basic training course and testing offered by the International Society of Arboriculture.