Caring For Trees During Drought

Many regions in the country have been suffering through a prolonged drought. Recognizing a drought can be difficult if you have just moved to an area or are unaware of the long-term conditions. For example, the pattern and frequency of rainfall is measured to determine drought above the total amount of rain. An area can receive more rainfall in a year that is above normal levels and still be in a drought.

Recognizing an area affected by drought can simply occur through the symptoms trees and plants exhibit. Immediate visible effects of drought damage include wilting, scorch, and some defoliation due to loss of turgor in plant cells, irreversible shrinkage of cell membranes, and increased synthesis of abscisic acid. Long-term symptoms of drought include dieback of branches and death of the plant as the plants capacity to absorb water is damaged. These are the primary or direct effects of drought.

Secondary effects of drought include a plant or tree’s heightened susceptibility to disease and insect invasion. Disease and insect invasion can occur with any conditions but during a drought disease such as root rot, cankers, wood rot and wilt do increase.

If your trees are showing the following symptoms, it could be due to drought injury:
•    Leaves that scorch and become brown on the outside edges or brown between veins.
•    Leaves that wilt, curl at edges and yellow.
•    Evergreens whose needles turn yellow, red or purple.

If your tree is suffering from drought there are some actions you can take to help keep it alive and healthy. The first includes proper watering. When watering your trees, water to a depth of twelve inches below the soil’s surface. This means you must saturate the soil within the dripline or the outer edges of the tree’s branches. For evergreens, water three to five feet beyond the dripline on all sides of the tree. You want to water your trees slowly, this allows the water to seep deep into the ground and not just run off the surface. Many people feel that if they dig holes in the ground, the water will seep deeper into it – when in fact, digging holes can just dry out your roots. Spraying your leaves is inefficient as well and should be avoided during a drought.

How much water do you give a tree during a drought? The rule of thumb is to use approximately 10 gallons of water per inch of trunk diameter, for each watering. Measure the tree’s trunk at knee height. The formula then follows – Tree Diameter x 5 minutes = Total Watering Time.

If you are using a hose, as most people do when watering, you may wonder how many gallons it will produce in a given amount of time. This can depend on your water pressure, but a hose at medium pressure will take approximately five minutes to produce ten gallons of water.

Trees should be watered year around with emphasis between April and September.  Mulching around your tree will also help reduce moisture loss. It is recommended to use four inches of mulch. You can use wood chips, shredded bark, leaves or evergreen needles. One should avoid using stone or rock as it increases air temperatures and can add to the moisture loss.  Place your mulch six inches from the trunk of the tree.

One should not fertilize a tree that is under drought stress.  Fertilizers stimulate growth, which can result in too much leaf area on the plant for the root system to maintain.

To help maintain your tree’s health during a drought you will want to treat it as a sick patient. Care is needed such as keeping it free from stresses, keeping it properly pruned, and cutting back on any applications of herbicide in the root zone.

Taking special care of your tree during a drought will save you the time and money of having to remove it and replace. With just a little time invested, your trees can remain healthy and happy in all conditions.

About the Author: Andrew Johnson is the owner of Central Texas Tree Care, a leading provider of Austin tree services in Central Texas. Certified ISA Austin arborist services including: tree trimming, tree removal, tree care and stump removal. For more information on Austin tree service please visit

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Spring Tree Care

Spring is upon us and it’s that time to take special care of your trees.
A tremendous amount of growth occurs during spring due to the stored nutrients the tree holds throughout winter. By the end of spring, the tree has used up most of these nutrients and will begin the process of photosynthesis or the making of new supplies of nutrients. In some cases, a tree may only have enough nutrients stored to begin leafing out but not enough to continue growing.  This is why it is critical not to do your heavy pruning after spring.

Most routine pruning can be done year around with little effect on the tree. You can prune to remove weak, diseased, or dead limbs. As a rule of thumb, growth is maximized and wound closure is fastest if pruning takes place before the spring growth flush. Some trees, such as maples and birches, tend to “bleed” if pruned early in the spring.  A few tree diseases, such as oak wilt, can be spread when pruning wounds allow spores access into the tree. Susceptible trees should not be pruned during active transmission periods.

Proper tree care of course occurs year around. So how can you care for your tree? Soil moisture is primary and yet not as easy as it may sound. Too much moisture or even too little can cause the tree to begin dying back. Tree soil needs to be moist between 12 to 18 inches of depth. You can check moisture depth by carefully digging or by using a soil probe after watering the root area.

Many people make the mistake in believing they are watering their tree when watering their yard. Trees do not typically get enough water this way. The lawn, which is competing with the tree, soaks up most of the moisture. Secondarily, thatch in the lawn will act as a water repellant. A better choice for watering your tree is to use soaker hoses or root waterers.  Water must be applied all year around, even in dry winter periods.

The type of soil your tree is planted in is also important. There may be a variety of soils beneath your trees, from clay and alkaline to sand and silt. Determining what type of soil is beneath your trees will help you take steps in improving it. If you have a lot of clay soil, you may need to aerate it often to provide it with enough oxygen.  If the soil is lacking nutrients you may have to fertilize it – not as much as you would in fertilizing the lawn.

To fertilize your trees, wait until the ground has completely thawed. This way the fertilizer will seep into the soil and not run off. As the weather warms, you can also begin removing tree wraps, if they have been used throughout the winter.

As for pruning your tree, you will want to do this in the spring as well, prior to the tree leafing out. To prune your tree, begin by removing damaged branches.

If you don’t have trees to care for yet, now is the time to put them in the ground.  Visit your local nurseries and greenhouses for suggestions and recommendations for your area.

About the Author: Andrew Johnson is the owner of Central Texas Tree Care, a leading provider of Austin tree services in Central Texas. Certified ISA Austin arborist services including: tree trimming, tree removal, tree care and stump removal. For more information on Austin tree service please visit

How Agroforestry Works For Everyone

It is a term not commonly heard, it is agroforestry. The word means to intentionally combine agriculture and forestry to create integrated and sustainable land-use systems. Agroforestry takes advantage of the interactive benefits from combining trees and shrubs with crops and/or livestock. It is also defined as:

“Agroforestry is a collective name for land use systems and practices in which woody perennials are deliberately integrated with crops and/or animals on the same land management unit. The integration can be either in a spatial mixture or in a temporal sequence. There are normally both ecological and economic interactions between woody and non-woody components in agroforestry”. -World Agroforestry Centre (ICRAF) 1993″

How is agroforestry used? In many ways, they include:

1.    Alley Cropping – This is a form of cropping applied by farmers to combat soil erosion. This helps increase the diversity of farmland as a means for crop diversification. In this practice, crops are planted in strips in the alleys formed between rows of trees or shrubs.  With this type of planting, crops are given shade in hot, dry environments, thus reducing water loss. This also helps retain soil moisture and provides a wildlife habitat. The trees used in this system can produce fruit, fuelwood, fodder or trimmings that can be converted into mulch. Fine hardwoods such as walnut, oak, ash and pecan are favored species in alley cropping systems, which can give a potentially high-value in lumber.
2.    Forest Farming – This is also known as ‘shade systems’. This system integrates the cultivation of both timber and non-timber forest products in a forest setting. With forest farming, the farmer cultivates high value specialty crops under the protection of a forest canopy. These crops include ginseng, shiitake mushrooms, decorative ferns that are sold for medicinal, culinary and ornamental use.
3.    Riparian Buffer and Integrated Riparian Management – Riparian forest buffers are natural or re-established streamside forests made up of tree, shrub and grass plantings. These plantings are placed along lakes, streams, rivers and wetlands in order to enhance and protect aquatic and riparian resources as well as generate income from timber and non-timber forest products.  Plantings also buffer non-point source pollution of waterways from adjacent lands and reduce bank erosion.
4.    SilvoPasture – Silvopasture combines trees with forage and livestock production. Trees are managed for high-value sawlogs and shade for livestock and forage. Conifers or hardwoods for timber or Christmas trees are often planted. Some nut and fruit orchards may also be grazed.
5.    Windbreaks – Planting trees in a linear fashion helps enhance crop production, protect people and livestock while benefiting soil. Field windbreaks protect wind-sensitive crops and control erosion, and increase bee pollination and pesticide effectiveness. Livestock windbreaks help reduce animal stress and mortality, reduce feed consumption, and help reduce visual impacts and odors. Living snowfences keep roads clean of drifting snow and increase driving safety. They can also spread snow evenly across a field, increasing spring soil moisture.

Agroforesty is also used to keep down dust, odors, reduce noise, provide green space or visual aesthetics, enhance wildlife habitat and offers carbon sequestration.

About the Author: Andrew Johnson is the owner of Central Texas Tree Care, a leading provider of Austin tree services in Central Texas. Certified ISA Austin arborist services including: tree trimming, tree removal, tree care and stump removal. For more information on Austin tree service please visit

Defining Hardiness Zones

When buying a tree or plant, you will notice an indicator on the tag of that tree or plant stating its hardiness zone. So what is a hardiness zone? It is defined as a geographic area in which a specific category of plant life is capable of growing, as defined by climatic conditions including its ability to withstand the minimum temperatures of the zone. These zones were first developed by the United States Department of Agriculture and have been updated as late as 2006 to compensate for global warming.

The USDA first issued its standardized hardiness zone map in 1960, and revised it in 1965. A new map was issued in 1990, based on U.S. and Canadian data from 1974 through 1986 (and 1971-1984 for Mexico). The new 1990 map included divided temperature zones broken into five-degree a/b zones for greater accuracy.

According to the Arbor Day Foundation, the Plant Hardiness Zones divide the United States and Canada into 11 areas based on a 10 degree Fahrenheit difference in the average annual minimum temperature. (The United States falls within Zones 2 through 10). For example, the lowest average temperature in Zone 2 is -50 to -40 degrees Fahrenheit, while the minimum average temperature in zone 10 is +30 to +40 degrees Fahrenheit. If a range of zones, for example, zones 4-9, is indicated, the tree or perennial is known to be hardy in zones 4, 5, 6, 7, 8, and 9. Suitable hardiness means a plant can be expected to grow in the zone’s temperature extremes, as determined by the lowest average annual temperature.

There are many benefits as well as drawbacks to the hardiness zone system. One drawback is that the zones do not incorporate summer heat levels into their zone determination, which means places that have extreme heat and cold could be marked for its cold zone and neglect the heat factor. Hardiness zones also do not take into account the reliability of the snow cover. Snow can act as an insulator against extreme cold, protecting the root system of hiberating plants. If snow is consistently covering the ground, it can actually lower the temperature of what the roots are exposed to.

Many factors are taken into consideration when planting trees and plants that hardiness zones do not incorporate. Some of them are: soil moisture, humidity, the number of days of frost, and the risk of a rare catastrophic cold snap.  For farmers, the probability of getting a particularly severe low temperature could be very detrimental and the knowledge of this could be more useful than just average conditions.

The last drawback of the system is the fact that although a plant will survive under particular lower temperatures, it does not mean it will flower sufficiently. For a tree to flower it requires vernalization or a particular duration of low temperatures.  Some publications are integrating such information into their hardiness zone maps. This additional information can include precipitation, wind patterns, elevation and length and structure of the growing season.

The National Arbor Day Foundation in the United States recently completed an extensive updating of U.S. Hardiness Zones in 2006. The maps include the most recent 15 years of data from more than 5,000 National Climatic Data Centers across the United States.

About the Author: Andrew Johnson is the owner of Central Texas Tree Care, a leading provider of Austin tree services in Central Texas. Certified ISA Austin arborist services including: tree trimming, tree removal, tree care and stump removal. For more information on Austin tree service please visit

The Most Colorful Tree- Rainbow Eucalyptus

When we think of trees and color, we typically imagine the tree’s leaves. But there is a tree known for its colorful bark. And unlike any other tree, the bark is made up of brilliant fluorescent colors, giving the tree the name Rainbow Eucalyptus.

To first see the Rainbow Eucalyptus, you might think somebody vandalized the tree or poured paint all over it. How can a tree have so many bright, almost fluorescent colors on it? But the bark is authentic.  The Rainbow Eucalyptus, also called Eucalyptus deglupta, Mindanao Gum and Rainbow Gum, is naturally found in the Northern Hemisphere. It naturally grows in New Britain, New Guinea, Ceram, Sulawesi and Mindanoa. Others grow the tree and cultivate it now around the world for its pulpwood, which is used in paper.

Of course the tree is also grown for ornamental purposes. The bark, which is patchy and sheds at different times, is bright green, blue, purple, orange, yellow and then maroon, each colors showing its aging process.  The tree grows almost 100 feet tall.

This eucalyptus can be grown in the United States in warmer climates. The Hardiness Zone for these trees is 9-11, 26 to 28 degrees, but only for brief periods. The tree does require warmth, has a low tolerance for intense or prolonged frost and requires an abundance of water. If growing the E. Deglupta in a container NEVER let it dry out, as it can prove fatal – these trees do dry out quite quickly.  For landscaping purposes, many plant their rainbow eucalyptus near freshwater ponds, lakes or canals. Mature trees can survive in drier areas but they do their best when having access to abundant moisture.

The eucalyptus is an evergreen. It also requires full sun to light shade, but of course prefers full sun. The tree is easy to keep fertilized and is not fussy about food, fertilizing yearly is sufficient. The eucalyptus also is adaptable to different soils, but likes soils that are well drained.

The E. deglupta, like other eucalyptus, are mostly pest free. An occasional mealybug or aphid may appear or even a caterpillar or leafcutting bee, but these trees typically can be grown without pest damage.

The Eucalyptus tree on its own has been a valuable resource as it grows fast and under many conditions. There are over 600 species of Eucalypts. Many of these trees are good for fuelwood and pole production. Because the tree grows so fast, it can build up stresses and lead to distortion, which makes it difficult to cut into potential timber. Eucalyptus is also resistant to termites which means it doesn’t have to be treated, as other wood might – thus helping the environment. On the downside, these trees require a lot of water. It is suggested not to plant them near food crops and plants that also need a lot of light and water as they will compete with each other. The benefit of this tree being a water hog is that it is sometimes used to drain swamps, which in turn reduces the risk of malaria.

Eucalypts belong to the family Myrtaceae. The flowers tend to be groups into inflorescences (with the exception of E.globulus which has single flowers). Bark varies from ribbed to the smooth and can be distinctly deciduous.  The leaves are also variable in both shape and color.

The Eucalyptus tree is also known for its fragrant oil. The oil can be used for cleaning and functions as a natural insecticide.

Each Eucalyptus tree has its own look and offerings. As for the Rainbow Euclapytus, it is mostly known for just being quite unique.

About the Author: Andrew Johnson is the owner of Central Texas Tree Care, a leading provider of Austin tree services in Central Texas. Certified ISA Austin arborist services including: tree trimming, tree removal, tree care and stump removal. For more information on Austin tree service please visit

Preparing Your Trees For Summer Storms

When it comes to protecting trees and plants, people often think winter takes the hardest toll. But summer and the storms that can come with it – from wind to strong rains, can be just as hard on trees as ice. Depending on your region, the wind and rain can actually be quite devastating to trees, if you are not prepared.

Most trees can biologically adapt themselves to wind and ice during an average annual growing season due to the fact trees can sway in the wind and these movements strengthen the woody material developing the stem and limbs. But, during the spring and summer months, many areas receive strong rainstorms, lightening and wind. The winds shift sometimes bringing in violent thunderstorms and occasionally tornados in some areas. Other areas have hail and flooding to deal with. Whatever the situation, it is most likely to make your trees vulnerable. Heavy rains cause healthy roots to weaken their hold. Winds can snap brittle branches.

There are typically six ways a tree is damaged by a storm. They include blowing down from the wind, stem failure, crown twist, root failure, branch failure and lightening strike.

FEMA (Federal Emergency Management Agency), which is a branch of the U.S. Department of Homeland Security, states that “Three-fourths of the damage that trees incur during storms is predictable and preventable.” Even one’s best efforts cannot prepare a tree to withstand the fiercest of winds, however, there is a lot of preparation you can and should do to greatly diminish potential storm damage to your trees. This usually requires watching for defects and vulnerabilities in trees and addressing them right away.

Here are some defects to watch out for that makes trees more vulnerable to wind and other severities of the weather:
•    Dead wood is number one. This kind of wood is unpredictable because it is brittle, and cannot give under pressure like living tree branches. What dead wood do you have in your trees that needs to be removed?
•    Cracks are clear indicators of potential branch failure, where there will be splitting sooner or later.
•    Poor tree composition (branch structure). This one is difficult for the average person to identify, but you can start by looking for excessive leaning, long horizontal limbs, crossing branches that rub against each other and create wounds, and narrow crotches (V-shaped instead of U-shaped). Trees with two trunks or leaders that are of identical diameter and have a narrow crotch need special care. To prevent splitting, choose one to be made dominant by stunting the growth of the other through pruning (called subordination).
•    Decay, as evidenced by fungal growth or hollow cavities, is a sign of weakness.
•    Pests can exacerbate a tree’s health problems, but they typically target trees that are already sickly.
•    Root problems, such as stem-girdling roots, while sometimes harder to detect, have the most impact on a tree’s inability to stay upright. Weak roots and a thick canopy is the deadliest combination during a storm.
•    A thick canopy. Can you see some sky through the tree? Keeping your trees thin is the single most important thing to do to “storm-proof” them. Quite simply put: the thicker a tree is, the more susceptible it is to damage in heavy winds. Even for a tree that is otherwise perfectly healthy, overly dense foliage poses a safety hazard during stormy weather. A dense canopy will not allow the wind to easily pass through, and the resistance to wind can cause branches to break or even bring the entire tree down. This especially applies to weight at the ends of branches, which is why stripping only the lower parts of the branches is not adequate (and leaves the tree with a funny lion-tailed look).

If you have identified problems in your trees such as the above, contact a professional arborist or tree specialist to help you detail out a plan in addressing your trees health and finding ways to strengthen them if possible, before storms cause more damage.

About the Author: Andrew Johnson is the owner of Central Texas Tree Care, a leading provider of Austin tree services in Central Texas. Certified ISA Austin arborist services including: tree trimming, tree removal, tree care and stump removal. For more information on Austin tree service please visit

Trees And How They Make Streets Safer

Trees have been known to have hundreds of benefits. But who would guess that they can make streets safer. And despite the fact many traffic engineers have felt that trees are dangerous for motorists as they narrow lanes and  obstruction things like parked cars, other engineers have proven this theory wrong. How?

Studies have been made on the correlation between streets and accidents and streets that are wide open and streets that are tree lined. It has been shown that streets that are wide-open seem to encourage motorists to speed and therefore with speeding comes more accidents. On the flip side, streets that are tree-lined encourage motorists to slow down and drive more cautiously – which of course means fewer accidents.

It seems, trees provide visual cues to drivers about their speed and send signals back to them for potential of collisions, which in turn makes the driver slow down. Trees also create physical barriers between motorists and pedestrians and trees seem to make drivers calmer.  As for their other benefits, trees give shade on hot days, absorb exhaust, produce oxygen and can even extend the life of pavement by 40 to 60 percent.

Eric Dumbaugh, an assistant professor of transportation at Texas A&M is the man who decided to prove his theory of how trees created safety rather than detriment on streets. He published his findings in the Summer 2005 issue of the Journal of the American Planning Association. Among the cases cited in his JAPA article are these:

* A study of five arterial roadways in downtown Toronto found that mid-block car crashes declined between 5 and 20 percent in areas where there were elements such as trees or concrete planters along the road.

* Urban village areas in New Hampshire containing on-street parking and pedestrian-friendly roadside treatments were two times less likely to experience a crash than the purportedly safer roadways preferred by most transportation engineers.

* A study of two-lane roadways found that although wide shoulders were associated with reductions in single-vehicle, fixed-object crashes, they were also associated with a statistically significant increase in total crashes. A rise in multiple-vehicle crashes offset the decline in fixed-object crashes.

* An examination of Colonial Drive (State Route 50), which connects the north end of downtown Orlando to the suburbs, found fewer serious mid-block crashes on the livable section than on a comparison conventional roadway. According to Dumbaugh, the conventional roadway also was associated with more injuries to pedestrians and bicyclists.

Dumbaugh followed up his experiment with an article on findings he examined safety on three routes- State Routes 15 and 44 in DeLand, Florida, and State Route 40 in Ocala, Florida. Each of these routes have pedestrian-friendly designs along parts of their length and conventional designs along other sections. Dumbaugh discovered that the pedestrian-friendly segments experience 40 percent fewer crashes than comparison roadways.

Having this information has helped city governments integrate more trees into their landscapes, an idea they have liked all along, not only for safety reasons but also because for planners, streets are more than throughways for traffic. They are also public places where people walk, shop, meet and engage in various social and recreational activities. This in turn creates pedestrian friendly streets that are highly desired by homebuyers, thus driving the value of homes up.

Trees have value in nature as well as in public places, aesthetically, environmentally and now for safety.

About the Author: Andrew Johnson is the owner of Central Texas Tree Care, a leading provider of Austin tree services in Central Texas. Certified ISA Austin arborist services including: tree trimming, tree removal, tree care and stump removal. For more information on Austin tree service please visit