How NOT to Kill a Tree
and
Best Smaller Tree Varieties

In my office, I have a poster that reads "How to Kill Your Tree - Let Me Count the Ways"! It describes the many ways humans commit arborcide. In fact, the actions of HOMO SAPIENS probably result in more tree deaths than all insects and diseases combined. I am not referring to such obvious practices as the felling of trees for forest products, but those practices which well?meaning humans exercise daily on urban trees. A noted tree pathologist, Dr. Paul Manion, has suggested that ALL trees in the urban environment are stressed, and this stress shortens urban trees' natural life span or results in their untimely death.

Many times, the action itself does not immediately kill a tree, but rather, sets in a motion a chain of events that ultimately shortens the tree's life. For instance, a wound may allow fungi decay to enter a tree. The tree and fungi begin to compete for the tree's carbohydrate reserves, resulting in a reduction of vigor. As the tree's health declines, borers and secondary fungi begin to invade the tree. Each contributing factor tips the scale against the tree, and in the end it succumbs to the accumulative effects.

What are these actions? The following are the 6 most prevalent ways to kill your tree, directly or indirectly.

1. IMPROPER USE OF STRING-TRIMMERS AND MOWERS. String-trimmers and mowers are the leading cause of tree death. These "Instruments of Death" completely girdle thin-barked trees like crepe myrtle and the Texas persimmon, or cause wounds which allow fungi and insects to enter the tree. An informal survey of several neighborhoods indicated that 75% of the trees had some level of mechanical damage. What makes this all so depressing is that the damage is avoidable. Mulch or the use of herbicides like Glyphosate or Fusilade would eliminate the need for these machines. Please stop the unnecessary wounding of your trees!

2. CHEMICAL ABUSE. After string-trimmer abuse, chemical abuse has to be the second greatest killer of trees. Most broadleaf herbicides kill trees as well as weeds and are able to move readily through the soil. Pramitol, a non-selective herbicide commonly applied to gravel driveways and beneath above-ground pools, will kill trees at a considerable distance from where it is originally applied. In fact, many alleged oak wilt centers are actually sites where herbicide was used recklessly or in ignorance. Weed and feed fertilizers are also notorious tree killers. They usually contain the herbicides dicomba, 2, 4-D, or both. In his book, Arboriculture: Care of Trees, Shrubs, and Vines, Dr. Richard Harris states that 2, 4-D has injured more non?target plants than almost any other herbicide. The only solution to this problem is for people to read the label thoroughly and keep these herbicides away from trees, shrubs and flowers.

3. IMPROPER PLANTING. Many people in San Antonio plant trees too deep, or in holes which are too small. A tree planted too deep, especially in our clay soils, will suffocate due to a lack of oxygen. Trees should be planted with their ball or container tops at grade level. A hole that is too small prevents the tender roots of a newly planted tree from growing into the surrounding soils, and the tree becomes root bound.

4. IMPROPER WATERING. Strange as it may sound, I've seen numerous cases where people have killed their trees by over?watering. Succumbing to the fallacy that if a little is good, a lot is better, these people have literally watered their trees to death! A young tree with 2 inches of wood chips or pine bark only needs to be watered every 10 to 14 days. The secret is to use mulch and to water REGULARLY and DEEPLY.

5. IMPROPER PRUNING. Improper pruning does not kill a tree outright, but it does weaken a tree to the point where other agents finish the job. Examples of improper pruning are topping, leaving stubs, and the removal of all branches on a limb except for a few at the end. A professional arborist can explain what proper pruning entails.

6. CONSTRUCTION DAMAGE. Many urban tree problems can be directly traced to the rhizosphere, that is, below ground. Construction activities such as building a house, patio, or driveway, damage tree roots. Likewise, trenching for utilities can cut vital roots that absorb water and minerals. Most people also forget that roots require oxygen. Raising the soil level, for example, will suffocate roots. Often the effects of construction damage are not immediately apparent. At one place I inspected, the live oaks did not die from a 2-foot grade change until 10 years later. Finally, one of the most disgusting practices is the paving around trees with asphalt or concrete. Eliminate this practice so that you please save me the nausea and you the trouble of removing the tree when it eventually dies.

These are only 6 ways to kill a tree-there are certainly others. All I can ask is to PLEASE be nice to your trees and THINK. All it takes is a little common sense.

And, last but not least, DO NOT plant a large-growing tree in a small space or too close to overhead structures and utility lines. Small trees are extremely useful in today's landscape because of size limitations such as utility lines, sidewalks, patios, garden homes, etc. Many small trees can be used for shading patios, west-facing windows or shade?loving under-story plants. Even more important is the fact that many of our small trees are very showy and make colorful additions to an otherwise drab landscape. These trees often are more appropriately used in groups, particularly odd numbers, rather than planted alone.

Recommended small trees (followed by their approximate height and a brief description) for this area are:

Desert Willow (15') - deciduous, graceful tree with leaves resembling a willow, pinkish?white blossoms throughout the summer. The 'Bubba' Desert Willow found by Paul Cox at the San Antonio Botanical Garden is my favorite.

Crape Myrtle (6' to 25', depending on variety) - often known as the "lilac of the south". It is a deciduous, multi?trunked tree famous for its smooth peeling bark, profusion of flowers throughout the summer, and its fall color. Hybrid varieties are resistant to powdery mildew--the size and color of these can be seen at:

http://aggie-horticulture.tamu.edu/plantanswers/trees/crape_myrtle_varieties.html

Loquat (15') - tough, evergreen tree, known for its clusters of bright orange, edible fruit following a mild winter.

Mediterranean Fan Palm (8') - graceful, multi?trunked palm with silvery?green foliage.

Mexican Buckeye (8') - deciduous, multi?trunked shrub or small tree resembling a redbud in spring, followed by attractive pods of buckeye?like seeds.

Mexican Plum (12') - deciduous, nonsuckering native plum covered with sweet?smelling white blossoms in the spring, followed by "edible" fruit in the summer.

Pindo (Jelly) Palm (10') ? bold, silvery?blue, feather palm known for its tropical?tasting, date?like fruit.

Possum-Haw Holly (10') ? deciduous native holly, literally covered with red?orange fruit in the fall and winter after the foliage has dropped, able to withstand wet or dry soils.

Texas Mountain Laurel (12') - beautiful evergreen, multi?trunked tree with purple Wisteria?like blossoms in the spring which smell like grape "Kool?Aid", must be grown in a dry, well?drained location.

Texas Persimmon (12') - tough, evergreen, multi?trunked tree with smooth, peeling gray bark, reminiscent of a crape myrtle, and "edible" black persimmons in the summer.

Texas Redbud (20') - deciduous tree famous for its profusion of hot pink blooms in the spring before the leaves emerge; will tolerate some shade. 'Forest Pansy' variety has deep purple new foliage.

Vitex (15') - Often known as "Lavender Tree" or 'Texas Lilac'; tough, deciduous, summer-blooming, multi-trunked tree with spikes of blue flowers and aromatic foliage; often used by the highway department along roadsides.

Windmill Palm (12') - Graceful, dark-green fan palm with a "furry burlap" trunk; looks great in odd?numbered groups and is very cold hardy.

Yaupon Holly (12') - Tough, evergreen, spineless holly with a profusion of small, bright red berries during the winter months.

All of the above trees are also Xeriscape (drought tolerant) trees which, at most, require one DEEP watering per month once established.