Frequently Asked Questions

Why should I hire a certified arborist?
International Society of Arboriculture (ISA) Certified Arborists have achieved a level of knowledge in the art and science of tree care through at least three years of experience and have passed a comprehensive examination. Certified Arborists are required to continue their education in order to maintain their certification. Therefore, they are more likely to be up to date on the latest arboriculture techniques. ISA Arborist Certification is a non-governmental, voluntary process. Certification can attest to an individual’s knowledge of proper tree care but cannot guarantee or ensure quality performance. Selection of a certified arborist should be based on the record of the individual arborist and the company at which he or she is employed.

How can I tell if a tree in my yard is hazardous?
Every tree has the potential to fall, but only a small number actually hit someone or something. It is a property owner’s responsibility to provide for the safety of trees on his or her property. Common defects associated with tree hazards should be identified. Evaluating the seriousness of the defects is best done by a certified arborist. Once a hazard tree is recognized, a prescription should be written recommending steps to reduce the likelihood of the tree falling and injuring someone.

Here are some common defects associated with tree hazards:

  • Large dead branches in the tree or falling on the ground
  • Detached branches hanging in the tree
  • Cavities or decayed wood along the trunk or in major branches
  • Mushrooms present at the base of the tree
  • Cracks or splits in the trunk or at the crotch where branches attach
  • Major branches arising from a single point on the trunk
  • Adjacent or nearby trees fallen over or dead
  • Trunk developing a strong lean
  • Roots broken off, injured or damaged
  • Leaves an unusual color or size
  • Electrical line adjacent to tree
  • Recent change in soil grade level (either higher or lower)
  • Recent construction in area
  • Recent topping or otherwise heavily pruned

What is topping and why does it hurt trees?
Homeowners often feel that their trees have become too large for their property. There are recommended techniques for reducing crown size. Toping is not one of them. Toping is removing 50 – 100 percent of the leaf-bearing crown of a tree by cutting the ends of branches. This practice can be very damaging to the tree both because of the location of the pruning cuts and the large number of wounds. It creates more problems than it solves. Topping may cause stress, decay, sunburn and weak branch attachments that are more likely to break off during a storm. Stressed trees are more vulnerable to disease and insects. A tree that has been topped is permanently disfigured. Pruning large trees can be dangerous. It is best to hire a certified arborist who can determine the type of pruning necessary to improve the health, appearance and safety of your trees. Performing the job safely reduces the risk of personal injury and potential damage to your property.

What are the different types of pruning that a large tree might need?
Landscape trees need a higher level of care than trees in a natural forest setting to keep maintain safety and appearance. Pruning is the most common maintenance procedure. The type of pruning needed depends on the homeowner’s goal for the tree.

Cleaning is the removal of dead, dying, diseased, crowded, weakly attached, and low-vigor branches from the crown of a tree.

Thinning is the selective removal of branches to increase light penetration and air movement through the crown. Thinning opens the foliage of a tree, reduces weight on heavy limbs, and helps retain the tree’s natural shape.

Raising removes the lower branches from a tree in order to provide clearance for buildings, vehicles, pedestrians and vistas.

Reduction reduces the size of a tree, often for clearance for utility lines. Reducing the height or spread of a tree is best accomplished by pruning back the leaders and branch terminals to lateral branches that are large enough to assume the terminal roles (at least one-third the diameter of the cut stem.). Compared to topping, reduction helps maintain the form and structural integrity of the tree.

Improper pruning can cause damage that will last for the life of the tree, or worse, shorten the tree’s life. Heavy pruning can be a significant health stress for the tree. Pruning should be done by a certified arborist who understands how the tree will respond to each cut. Pruning mature trees requires special equipment, training, and experience.

Should young trees be pruned?
Proper pruning is essential for a tree to develop with a strong structure and desirable form. Pruning of newly planted trees should be limited to corrective pruning. Remove torn or broken branches, and save other pruning for the second or third year. Each cut has the potential to change the growth of the tree. How a young tree is trained depends on its function in the landscape. Most young trees need to have a strong central leader. Trees that receive appropriate pruning while young will require little corrective pruning when they mature. It is important to use the right pruning tools. A certified arborist is trained in the proper techniques for pruning young trees and the safe use of equipment.

Do mature trees need special care?
A healthy tree increases in value with age. Regular maintenance, designed to promote plant health and vigor, ensures their value will continue to grow. Preventing a problem costs less than curing one once it has developed. Regular tree inspections can prevent or reduce the severity of future disease, insect and environmental problems. A certified arborist will examine leaves or buds, leaf size, appearance, twig growth, and note the condition of the trunk and crown. Crown dieback (gradual death of the upper part of the tree) and trunk decay are often symptoms of problems that began several years before. Maintaining mature landscapes is a complicated undertaking. You may wish to consider a Plant Health Care (PHC) maintenance program that will detect and treat any existing problems that could be damaging or fatal.

What should I do if I think my tree has a disease or insect problem?
Correct diagnosis requires a careful examination of the situation by a trained eye. Many plant health problems exhibit similar symptoms. A site visit from a certified arborist can usually determine the nature of the problem. Proper treatment is based on an accurate identification of the host plant and the causal agent. Diseases can be classified into two broad categories: those caused by noninfectious agents (disorders) and those caused by infectious agents (diseases). Infectious diseases include fungi, viruses, and bacteria. Most plant problems in urban areas are the result of disorders related to nutrient deficiencies, temperature extremes, vandalism, pollutants and fluctuations in moisture. Environmental stress weakens plants and makes them susceptible to insects and disease.

Why contact an arborist for plant health care?
While trees are the dominant feature in your home landscape, they share this area with turf grass, shrubs, and flowers. All these plants have one resource in common: the soil. The roots of trees, shrubs, turf grass and flowers intermingle and compete for nutrients and water in the soil. Fertilizers applied to your lawn can impact the appearance and vitality of your trees and shrubs. A Plant Health Care (PHC) program is a holistic approach to managing the health of all plants in the landscape. Trees and shrubs are the focus of the program because they represent a long-term investment in your landscape. Bedding plants can be replaced in a few shorts weeks and a lawn in a single growing season, but it can take a lifetime or more to replace a mature tree. A PHC program involves monitoring tree and shrub health. It allows problems to be detected and managed before they become serious.

What can be done to maintain healthy grass and trees in the same landscape?
Proper planning and maintenance are required for trees and turf to be compatible. Thinning grass under large shade trees, surface roots that are raised above the soil line, trunks damaged by lawn mowers or trimmers are all undesirable effects of trees and turf growing too closely together. Maintenance practices for trees and turf are different, and treatment of one can unintentionally damage the other. Tree and grass roots exist together in the upper 6 to 8 inches of the topsoil where they compete for oxygen, water and nutrients. Most grass species will not grow well in areas that get less than 50 percent open sunlight. By selecting shade tolerant grasses for your area, planting trees that do not root near the surface and protecting the critical root zone with a mulched island that extends out to the drip line, you can eliminate many of the problems that develop when trees and turf coexist.

How can I tell if trees on a lot will be damaged during construction?
Many municipalities have ordinances that prohibit trees from being destroyed or damaged without a permit. This may include physical injury to the crown, trunk and roots. A certified arborist with experience interpreting local tree ordinances and knowledge of the permitting process can save you time and money by determining which trees can be saved and creating a plan to protect those trees.

An accurate determination of tree species, size, location, health and condition may influence whether trees to be removed must be recompensed.

What are some of the ways that trees may be damaged by construction?
Construction equipment can injure the above ground portion of trees by breaking branches, tearing the bark and wounding the trunk. Tree roots can extend far out from the trunk up to three times the height of the tree. Roots can be damaged by soil compaction when heavy equipment drives over the ground. When dirt is piled up around trees or the grade increased trees roots can suffocate. The fine, water and mineral absorbing roots of a tree are found mostly in the upper 6 to 12 inches of the soil. Digging and trenching can cut root support causing the tree to eventually fall or blow over. Trees damaged by construction may not die immediately, but decline over a period of years.



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