TLC for Trees
by Harold Spiegel

Winter does not signal the end of the growing season for trees. Rather, it marks the beginning of the next phase of life. Growth for trees is a continuous loop.

Many changes occur in trees with the reduction of daylight, increased moisture, and cooler soil and air temperatures. Leaves are shed to replenish the soil with organic matter, but leaf and flower buds continue to develop. Roots are sloughed and with decreased demands on their support, new roots begin to grow. During the winter, many pests and diseases are in a dormant state.

The timing is perfect to give your trees a little tender loving care. TLC for trees includes pruning, fertilizing and using environmentally sound pest control methods.

Pruning is important to remove dead or diseased limbs and parasitic mistletoe. With the lack of foliage during winter, cracks and other structural defects are revealed. Parasitic mistletoe also is easy to spot and effectively remove during winter.

Here's another advantage of pruning during the winter -- without leaves on the tree, there is far less mass for disposal. Limbs can be chipped and the chips can be hauled away or left for mulch. Logs can be added to the woodpile for burning next season. The few leaves that remain can be raked and added to a compost pile or left to decompose and nourish the soil. Evergreens, such as live oaks, should have excessive growth removed to minimize breakage in the event of winter storms. Crown thinning reduces limb end weight and allows for light filtration to plantings beneath the tree. However, stripping out the interior growth creates a structurally unsound tree. Improperly pruned trees commonly resemble giant stalks of broccoli. Before pruning, take a look at the bare trees in your neighborhood. The architecture of the natural branching structure is amazingly beautiful. The end result of pruning should be a structurally sound, balanced, healthy and aesthetically pleasing tree.

Fertilize trees by amending the soil to support the activity of the root system. Trees are not 'fed' directly. Organic materials or amendments added to the soil encourage beneficial organisms in the soil to create nutrients for uptake by the tree's root system.

A critical element of root growth is oxygen. Whether done by professionals or the homeowner, aerating the top eight (or more) inches of soil can greatly improve root growth.

Garden centers have many products for soil aeration. Using a heavy tined 'potato fork' is a good way to aerate and create avenues for supplements to reach the tree's root zone.

Professional tree services use specialized equipment and supplements specifically blended for local soil conditions to achieve the best results. The more aeration -- the better!

Winter is a great time to apply dormant oil to control scale insects and mites, which hide in the cracks and crevices of tree bark. Dormant oil is a highly refined, non-toxic form of mineral oil. Scale insects and mites can go undetected because they are tiny. However, don't let their small size fool you! These pests can cause twig and limb death and depending on the level of infestation, they also can cause distorted foliage. A thorough application of dormant oil suffocates the eggs, adults and immature scale insects and mites by covering them with a thin layer of oil. Extremely heavy infestations may require early and late season treatments.

Temperature ranges, wind and moisture conditions dictate the best time to apply dormant oil. The temperature should be below 75° F and above freezing for a minimum of 24 hours. Superior grade oil has a broader range of safe temperatures for application.

To avoid the oil being washed off, there also should be no rainfall for 24 hours. Care should be taken to avoid direct spray to windows and vehicles, however this can be removed easily with soap and water.

With a little tender loving care during the winter, your trees will continue to grow and beautify your yard for years to come.