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FAQ: Storm Damage, Tree Defects, & Hazards
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FAQ: BASIC TREE CARE PRACTICES:
I have a new house and have never cared for trees before. What do I need to know? It is best to have a professional evaluate your trees and see what recommendations are made. The following questions and answers cover some common recommendations and maintenance practices that will benefit most trees. What are some of the benefits of maintaining my trees? Trees in the urban/suburban landscape have traditionally
been valued for their aesthetic qualities and shade they produce. Especially
in settled areas, trees have many other My neighbors have told me that installing mulch rings around trees is good. Is that true? Yes, trees love mulch, if applied correctly. MULCHES: Homeowners and professional arborists depend on mulch in landscapes for several reasons. Functionally, mulches discourage weeds from growing, conserve moisture during drought periods, and allow better use of water by controlling runoff and increasing water-holding capacity of light, sandy soils. Mulches help maintain a uniform soil temperature. A 3- to 4-inch layer of mulch can add to the aesthetic value of a garden while protecting the base of trees from being injured by equipment, such as lawn mowers. Mulch rings also decrease competition from lawn grass. Lawn grass, especially when lush, robs trees of valuable nutrients and moisture. Many organic materials can be used as a mulch. Bark
mulches and wood chips are the two most commonly used mulches in most
of the country. In the south, pine needles are included in that list. Most arborists consider organic mulches as the most
compatible with trees. There are, however, several inorganic materials
used as mulches. These include weed barriers. IT IS RECOMMENDED NOT TO USE BLACK PLASTIC AROUND TREES: There are, however, several landscape fabric “mulches” available that will function the same as plastic, but allow for normal water and oxygen exchange. These materials, sometimes called geotextiles or weed barriers, are placed on bare soil around trees and shrubs with mulches used on top. There are many brands and types of materials from which to choose. They have proven to be beneficial in discouraging weeds and conserving soil moisture. Can my tree
really be damaged by a lawn mower? Yes, trees often are wounded by careless use of yard equipment like lawn mowers, weed whips, and other trimming equipment. These injuries cut through important vascular tissue just inside the bark, which can lead to decay and ultimately death of the tree. A bed of mulch around the tree eliminates the need to trim or mow close to the tree's base. Extreme care should be taken when digging up or tilling the soil under a tree. Many large and small roots will be cut by such digging, especially if it occurs close to the trunk. Why should my trees be pruned? Pruning trees, especially when younger, helps promote healthy trees with good branch architecture. Again, think of a tree in its native environment, the forest. There the tree is in stiff competition with other trees. It is forced to grow fast and upright to fill what is usually a very limited space. Trees growing in man-made conditions usually have much more space and less competition. They will spread out to form much broader trees than they would if located in the forest. The branch structure will often be inadequate if the tree is left to develop on it’s own. These trees can develop hazard limbs that eventually could fail, leading to an early tree death. Tree Pruning:
How do I know if my arborist will prune it correctly? Ask the arborist if they prune according to the American National Standards Institute standard for tree pruning, called ANSI A300 - Part 1 Pruning. ANSI A300 Part 1 Pruning • a statement that says all work will be performed
in accordance with ANSI A300. In addition to the information given on the work estimate, ANSI A300 Part 1 Pruning sets some guidelines for basic pruning practices that arborist should follow. If an arborist is adhering to the ANSI A300 Part 1 Pruning standard they: • will not leave branch stubs, I have a newly planted tree. Should
I prune it? It is generally recommended that some limited pruning
be done at the time of planting. I have two different recommendations from arborists on how to prune my newly planted trees. Why is this? Some arborists prefer to limit the amount of pruning done to a newly planted tree to give it a chance to get established. In this case the pruning will be limited to dead, dying, or diseased branches. This is the best option if the arborist will continue to care for the tree, making return visits in the future. Other arborists may recommend pruning to shape your tree for good branch development at the time of planting. This is probably the best option if no additional care will be given to the tree in the near future. Should I prune a young, established tree or is it better to just let it grow? It is important to prune young trees in order to develop a strong scaffold branch structure. Pruning of young trees can avoid more expensive problems that could occur if the tree is allowed to grow with branch defects. Pruning cautions: Many tree problems, and even maintenance requirements, can be avoided by knowing the growth habit of a specific tree. Find out how fast and how large a tree normally grows. See Select and Plant. Logic and reason also apply. For example, don't plant a white oak directly beneath utility lines. As the tree grows and interferes with the lines, the tree will be pruned. This could destroy the natural character of the tree and lead to its early decline and death. Warning: Home owners should limit their tree pruning to small, lightweight branches which can be reached from the ground or they could subject themselves to severe injury and even death. The pruning of large branches and/or working off the ground should be left to professional tree experts with proper equipment. A neighbor
said my tree care company should have used pruning paint to seal the
cuts. Is this correct? In the past, part of the standard recommendation was to apply a generous coating of a tree wound dressing to all fresh cuts. It was believed this would prevent decay-causing infection. However, research by the United States Forest Service Northeastern Forest Experiment Station proved that this practice works against nature's design and the trees' best interest. Research has proven that all of the wound dressings currently available do nothing to prevent decay, and some serve as a food source for microorganisms. They also can hold moisture against the cut wood, promoting the growth of decay-causing microorganisms. A light coating of non-toxic wound dressings can be used for cosmetic purposes. Wound dressing may also be recommended in some unique, limited situations, such as to control mistletoe or to discourage borer infestation that could spread diseases like Dutch Elm Disease. Consult your arborist for more information. How do trees close pruning wounds? Why didn’t my tree care company cut the limb right back to the trunk? When a tree is wounded, it sets up defensive walls against the invasion of decay fungi and other microorganisms. The vessels near the wound are plugged with gums, resins, and chemicals that resist the spread of decay. This creates protective walls within the tree. When decay develops in a branch, it moves down the branch until it reaches the protective walls. Once there, it stops. Generally, if the tree is healthy very “strong” walls can be erected and the decay can be stopped. If a tree is not healthy, it’s wall will not be as “strong.” Some trees have “genetically weaker” walls and do not do a good job at stopping decay. After initially forming the “walls,” the tree then attempts to cover over the wound with what is called woundwood. For branches and limbs, a region called the branch collar is where this protective chemical zone is located. The branch collar is located at the base of the branch or limb. Sometimes it can be seen as a slightly swollen area. When the branch collar is removed during pruning, such as when a cut is made flush to the trunk, it is called a flush cut. Flush cuts greatly increase the chance of the trunk becoming infected by decay and canker-causing microorganisms. Removing the branch collar (making a flush cut): • removes the protective chemical zone; A properly made pruning cut, called a collar cut, leaves the branch collar in tact. This results in a doughnut-like ring of woundwood forming all the way around the wound. With this type of pruning cut closure may take only a few months for small wounds. Larger wounds may take years to close, or may not close at all. The short answer is no. Topping, tipping, heading back and dehorning are all terms used to describe severe cutting back of a tree's crown. It is a poor arboricultural practice and should not be used for healthy tree maintenance. Topping: • destroys the tree's branch structure Though topping often leads to many large, fast-growing sprouts, these sprouts are attached to stubs that soon become rotten. The sprouts then become hazards as they grow larger. The common reason given for topping is to limit the growth of a tree, but this does not occur. In reality, the fast-growing, vigorous watersprouts will actually outgrow a similar-sized tree that has not been topped in about 5 years after the topping. Should I have my trees lion’s tailed? Again the short answer is no. Lion’s tailing is the
“gutting-out” of a tree by removing a large number of the inner branches.
The limb’s of the tree look like a lion’s tail after pruning. The limbs
will appear “long and slender” with a “puff” of foliage at the end. • is a form of over-pruning, too much foliage is
removed so that the health of the tree could be jeopardized; Trees pruned according to ANSI A300 Part 1 Pruning standards cannot be lion’s tailed because not more than 25% of foliage can be removed in a single year and 50% of the foliage should remain evenly distributed in the lower 66% of the canopy. When is
the best time to prune trees? The old arborist saying goes, “the best time to prune is when the pruners are sharp,” meaning that trees can be pruned at any time. This is still true for most trees, although there are some points to consider and some limited exceptions to the rule. My neighbor said I should only prune trees in fall or winter. Is this true? Pruning trees does not have to be limited to fall
or winter. Granted, fall and winter are good times to prune as the tree
is dormant. Points to consider when deciding when to prune: Birches, dogwoods, elms, hackberries, magnolias, maples, poplars, walnuts, willows, and a few other trees are known as "bleeders". When these species are pruned in late winter or early spring, the wounds may bleed. This flow of sap is more unsightly than damaging to the tree. In fact, sap at this time of year is roughly 98% water and 2% sugar, so little energy is lost through a bleeding wound. The sap flow will taper off and cease as the new leaves turn dark green and harden. Pruning these trees could be delayed until the leaves turn dark green and harden if you have aesthetic concerns. Exceptions: There are a few trees susceptible to insect and disease problems that could be encouraged if pruning is done at the wrong time. The most common example is Dutch Elm Disease. This disease has devastated the nation’s population of American elm trees. The fungal disease is spread primarily by the elm bark beetle (elms growing close together can spread the disease through their roots). The beetle is attracted to fresh pruning cuts when it is active in mid to late spring and early summer. It bores into the wood, spreading the fungal disease. Pruning of susceptible elms should not be done during this period to avoid attracting elm bark beetles. Similar diseases and infestations carried by boring beetles, but less widespread than Dutch Elm Disease, are Oak Wilt, most serious in the Mid-West and Texas, and Pine Wilt Nematode and Blue-Stain Wilt of pine, most serious in the Southeast. Eucalyptus borer infestations can be a problem for eucalyptus trees in the western United States. Tree care professionals may recommend that pruning of susceptible pines, oaks, and eucalyptus trees be avoided 1) when boring beetles are active and 2) if diseases they might carry are prevalent in your area. Fireblight is a very different disease, but its spread can be avoided by correct timing of pruning. Fireblight is a bacteria that infects ornamental and fruit trees in the Rose family. It is most serious on apples, crab apples, and pears. The disease is spread by rain water, especially when the trees are in flower. Avoid spreading this disease by not pruning when these trees are in flower or when it is raining. A similar disease spread by rainfall is Cytospora Canker of spruce, most serious in the northern tier of the United States. Avoid pruning spruce when it is raining if Cytospora canker is a problem in your area. Avoid pruning these trees during rainy weather: • Rose family trees such as apples and pears That depends. Your trees will need watering if they are newly planted or your area is suffering from drought conditions. If you are receiving normal or close to normal rainfall for your area, then you should not have to water your established trees. Exception: If you live in a dry or desert area, or have sandy soil, and someone has planted a tree not suited for these conditions, then the trees may require more water than even normal rainfall can provide to survive. Depending on the cost and availability of water in your area, it may be better to replace such trees with others better adapted to your local environment. See Selection and Planting of Trees. Installing mulch will conserve soil moisture and reduce the amount of water needed. See Mulches. If you are installing an irrigation system you need to consult a professional arborist to be certain that first, the installation will not harm existing trees, and second, that the irrigation programming is set for the tree’s watering requirements, not just the turf grass. Moisture is critical to trees, but too much moisture can cause serious damage. The amount of water to apply depends on the tree. Watering newly planted trees: Watering should be
done at the time of planting to settle the soil and to assure adequate
soil moisture. The first watering is normally done by the planting crew
soon after planting. After the first watering, adequate water must be
provided by the property owner unless there has been sufficient rain
to keep the soil moist. The critical months for watering are May through
September (this period of time may be extended in warm climates). Selecting
the proper plant is very important for dry, desert-like climates to
avoid heavy watering requirements. It is usually recommended to choose
plants that are suited for dry conditions; this type of landscaping
is called xerophytic. Most trees need to be watered for 2 or 3 years
after transplanting to provide adequate soil moisture while root systems
are becoming established. In the past it was recommended that a “saucer”
be formed around the soil ball to make a water-holding reservoir. Recent
studies have shown that this practice actually encourages roots to stay
in the area of the soil ball instead of growing into the surrounding
soil. This can increase the time it takes for the tree to get established
in the landscape. It is now recommended that the root ball and surrounding
area of a newly transplanted tree be watered. A 3-inch diameter tree moved by a tree spade may require 60 to 80 gallons of water every 10 days if rain does not occur. Distributed soils are frequently high in clay subsoil and tend to drain poorly. If these conditions exist, watering for a prolonged period of time may result in over watering and cause the roots to drown from lack of adequate soil aeration. Adding large quantities of water too frequently to heavy clay soils is detrimental and will result in death of the tree. Conversely, waiting until the tree wilts and the leaves start to turn brown is too late to water. Watering established trees: Large trees can be watered
with lawn sprinklers. Apply water at rate of 1 inch per watering, 2
inches if there is vigorous lawn grass near and under the tree. Water
at a rate low enough to keep water from running off. Do not water daily,
this can damage your tree by suffocating it’s roots. Instead plan your
watering based on the severity of the drought conditions. Generally
anywhere from once every two weeks to once every 4 to 5 days will suffice. Trees often require fertilization at some point in
their life span. Remember, most tree’s natural environment is the forest.
There nutrients are continually recycled as leaves and other plant,
and even animal material, fall and decompose on the forest floor. When
you put a tree in a landscape setting it is usually deprived of these
nutrients. • a slow rate and low amount of annual growth on
twigs and trunk, Trees that possess these symptoms generally would
respond to a fertilization treatment. One should make sure that nutrients
(or lack of) are the problem before fertilizing. Other common tree disorders
to be aware of in urban areas would include poor planting techniques,
moisture problems, construction damage, girdling roots, or utility leaks
from a natural gas line or sewer line. How does the arborist determine when to fertilize? Why does my tree need a soil test? Arborists have a number of tools at their disposal. The best is the arborist’s knowledge of local soil and environmental conditions. The arborist may be able to make a fertilization recommendation simply by examining your tree and yard. This saves the client time and money. On other occasions the problem may be more complex and the arborist will recommend a soil and/or foliar analysis to determine the problem.Your arborist does know that most shade trees growing in landscape settings will need nitrogen. Nitrogen is not stable in the soil. It is easily washed away by water and may periodically need to be replaced. The arborist said the problem with my tree isn’t lack of nutrients but soil pH. What does that mean? Before recommending a fertilizer, the arborist may note that other problems need to be addressed. An improper soil pH often makes it more difficult for a tree’s roots to absorb needed nutrients, even when those nutrients are abundant in the soil. Generally a pH range of 5.2-6.2 is the most desirable. Acid soils are sometimes limed to raise the pH, but more commonly, basic soils are treated with sulfur to adjust the pH downward. Maintaining a soil pH range of 5.2-6.2 for shade trees generally insures that essential plant nutrients will be available to the tree. How do
I know if the arborist is using the correct type of fertilizer at the
correct rate? What is the fertilization standard? First, ask the arborist if they are applying fertilizer in compliance with the American National Standards Institute standard for tree fertilization, called ANSI A300 - Part 2 Fertilization. ANSI A300 - Part 2 Fertilization Commonly, the preferred type of fertilizer is slow-release fertilizer with a nutrient ratio of 3:1:1 or 3:1:2 for shade trees, and 3:1:3 for palms. The preferred rate of fertilizer for slow release is between 2 to 4 pounds of actual nitrogen (N) per 1000 square feet. Usually, it is recommended to avoid applying over 6 pounds of nitrogen in a single year. The fertilization area is basically the root zone of the tree. The fertilization area is generally considered to be from near the trunk to near or beyond the shade canopy (dripline) of the tree. Roots can grow much further from the tree, however, so the arborist may recommend adjusting the fertilization area to account for larger root zones. There are a number of fertilization methods such
as a granular surface application, sub-surface dry application, and
sub-surface liquid fertilizer injection. Generally, when a turf or ground
cover is growing in the fertilization area, a sub-surface fertilization
method is preferred. Your arborist may deviate from these common practices
for a number of reasons, such as to correct a nutrient deficiency or
to correct other plant health problems. The objective of the deviation
should be clearly stated in writing on the work estimate. What is a nutrient deficiency and why does it need to be corrected? What is iron chlorosis? Just like people, trees can have nutrient deficiencies
that lead to problems. The deficiency may cause the tree to exhibit
predictable symptoms that the arborist can use to diagnose the problem.
Other times testing and analysis may be required to determine the exact
nature of the problem. Here is an example of a common nutrient deficiency. Many trees suffer from iron deficiency induced by poorly drained or compacted soils or by soils with a high calcium content. These soils are characterized by pH levels above 7.5. The unavailability or non-utilization of iron commonly causes a condition called iron chlorosis, and is characterized by yellow leaves, slow growth, and branch dieback. Pin oak and silver maple frequently show this condition. Chlorotic trees exhibit partial or complete yellowing of the leaves. The yellowing first occurs between the veins, leaving a network of darker green veins on a greenish-yellow background More severe symptoms include smaller than normal leaves that turn pale yellow and develop angular brown spots between the veins. Leaf margins may turn brown. The leaf eventually curls, dries up, becomes entirely brown, and falls. Tips of affected branches may die, especially in the tops of broadleaved trees. If the condition is not corrected, it can cause poor root development, severe stunting, and plant death. Weakened plants also are very susceptible to other diseases and insect infestations. On junipers, pines, and other evergreens, chlorosis usually develops as an overall yellowing of needles. CAUSE OF IRON CHLOROSIS: Under alkaline conditions (soil pH above 7.0), iron changes to insoluble forms that are less available to growing plants. Iron is more soluble and most readily absorbed from the soil at a pH range of 5.0 to 6.5. Lack of available iron is aggravated by: 1) low temperature and high soil moisture, 2) relatively large amounts of copper, manganese or zinc, and 3) excessive phosphorus applications. CORRECTING IRON CHLOROSIS: There are three methods of applying iron salts to correct iron chlorosis in plants. They are: 1) applying a mixture of dry ferrous sulfate (iron sulfate) and sulfur to soil, 2) spraying the foliage with a solution of ferrous sulfate or iron chelate, or 3) introducing iron salts into the main stem or trunk of affected plants by implantation or injection. This is a case where the arborist might recommend a foliar spray or trunk injection to save the tree in the short term, and then recommend other treatments to correct the real cause, the high soil pH, in the long term. Can competition from other plants harm my tree? What is allelopathy? Often little thought is given to the effects of altering plant communities. For example, it is uncommon to see an attractive sugar maple growing in an attractive bluegrass lawn. Either the healthy sugar maple shades out the grass or the tree slowly declines due to competition from the lush, highly competitive grass. Allelopathy, the release by one plant of substances toxic to nearby plants, can alsobe a factor. Some allelopathic relationships, such as the effects of walnut on rose, are well known, but many are poorly understood. When is the best time of year to perform basic tree care operations? Many tree care activities can be carried out all
year long. For other activities there is a season. Spring and summer
give us the best opportunities to identify tree health Some will argue that, in temperate areas, fall and winter are the best times to prune. When the tree is bare, its branch architecture is easier to observe, so problems can be more readily corrected. Proper pruning at other times of the year will generally do no harm to trees, but there are exceptions. For instance, pruning an American elm when the beetle that carries Dutch elm disease is busy flying from infected to healthy host trees greatly increases the elm’s chances of infection. Pruning of deadwood only does not have the same effect and can be carried out any time. A tree is a complex, living organism. There are many different definitions for a tree and for each you can probably think of some exceptions. Webster’s defines a tree: 1a: a woody perennial plant having a single usually elongate main stem generally with few or no branches on its lower part. It also defines a shade tree: a tree grown primarily to produce shade. In general it can be said that trees: • Are perennial plants Specifically, trees can be divided into three categories: 1. Conifers usually have: 2. Shade trees usually have: 3. Plants that grow like, or are trained to
grow like trees. Examples: Interesting Note: Palms are routinely considered
trees, although technically they are more closely related to your lawn
grass than any shade tree or conifer! |
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Black
plastic is sometimes used to discourage weeds, however it interferes
with the normal oxygen and water supply to the tree’s roots. When the
plastic is used, a very shallow root system is created and during drought
periods the plants may not withstand the stress.
problems,
since a cursory inspection can tell whether the tree "looks"
healthy compared to previous years or nearby trees of the same species.
Diagnosis of the actual cause of the tree malady is a tricky business
best left to an expert. As with human illness, prompt detection and
treatment can be critical. Most pest management activities have a very
specific and narrow window of treatment that coincides with when the
pest is active on the plant and/or vulnerable to the treatment. Fertilizers
are best applied when the plant roots can actively uptake the nutrients.
Of course, the use of fertilizers on shade and ornamental plants should
be restricted to situations in which there is a nutrient deficiency.