By Calvin Finch, Conservation Manager, Water Resources & Conservation Department, San Antonio Water System, and Horticulturist
Week of April 22, 2002
SHADE TREES IMPORTANT
Shade trees are important to your landscape. They provide shade, property value, and are attractive. If you enjoy birds and other wildlife, the shade trees also provide habitat. As important as trees are to an individual landscape, they are even more important to the City as a whole. A healthy urban forest reduces polluting runoff, keeps energy costs in check, contributes to water conservation, and may help address air quality problems. Recognizing the value of the urban forest to the San Antonio environment and quality of life, a new group, the Alamo Forest Partnership was formed to assess the state of tree cover in Bexar County and then organize a tree planting program to improve the situation. Led by City Public Service (CPS), the Partnership includes Steering Committee members San Antonio Water System (SAWS), University of Texas at San Antonio (UTSA), City of San Antonio, San Antonio Trees, Texas Forest Service, Texas Parks & Wildlife, San Antonio Forests, U.S. Department of Defense, American Forests, Bexar Audobon Society, National Park Service, Neighborhood Resource Center, and Alamo Area Council of Governments.
Through April and early May teams of volunteers will be surveying the trees on 30, 2-acre sample sites to establish a baseline of tree numbers, tree health, and tree quality. The next steps will be to put a tree planting and care plan together so that in 10 years and further into the future the San Antonio area forest will be improved with the result of less energy use, less runoff, less lawn irrigation, more property value, better air quality, and more wildlife habitat. For more information on the Alamo Forest Partnership call Jenna Terrez (CPS) at 210-353-2792.
Container grown shade trees can be planted at anytime in the year. Select a tree species that will provide shade and beauty over a long period with a minimum of attention. Our recommended shade trees should be planted in full sun at least 10 feet from the house. Dig a hole that is the same depth as the container and 3 or 4 times as wide. Place the rootball in the hole and backfill with the native soil. Water-in the tree well at planting. The soaking will help insure that soil settles into every air pocket.
Adding root stimulants, fertilizer, or organic material to the planting hole is not necessary. Research indicates that the added expense does not improve growth rate or survival rate. In fact, a hole that is much easier to fill with water than it is to drain contributes to root drowning. A hole in some of our poorly drained clay soil filled with sand, compost, or potting soil fits that description.
Placing three to four inches of mulch such as leaves, shredded brush, or bark over the root system does contribute to tree survival and increases the growth rate. Water the tree when the soil under the mulch dries to one inch. When you irrigate, place enough water to wet the entire root zone (5 to 10 gallons).
My favorite shade trees for San Antonio include live oak, Mexican white oak, Texas red oak, Bur oak, Montezuma cypress, cedar elm, Mexican sycamore, chinkapin oak, Lacey oak, and Chinese pistache.
For smaller yards consider yaupon holly, loquat, vitex, Bradford pear, redbud, Oriental persimmon, desert willow, and Mexican plum. They are small trees that provide understory and some shade.