How NOT to Kill a Tree
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
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
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:
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
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.