Arborists are concerned with the health of trees. They generally work within a tree service and manage tree health and administer tree care. They assess tree health and structural condition, then write prescriptions for correction and improvement. Problem solutions generally consist of tree trimming and or plant health care. When trees are not in top physical condition, they are said to be stressed. Stressed trees exhibit physical symptoms. Arborists treat the physical symptoms (if necessary), then address the underlying conditions which produced the stress. Tree health is similar to human health in that a healthy tree tends not to become diseased or attract predators, but a weak tree is a magnet for disease or predators. If you restore the weak tree to health, the tree’s natural defenses are generally adequate to resist most disease and predators.
Top reasons for tree stress (in order of occurrence frequency)
- Watering too little or too much
- Crowding from other trees, greenery, physical structures
- Incorrect planting
- Mechanical injury below ground, and above
- Soil problems
- Improper pruning
Results of stress
- Poor health, poor appearance
- Fungal infections
- Bacterial infections
Some predators violate the “rule” about predators only attacking stressed trees. The Atlanta metro area has been more fortunate than many areas of the country where trees have been devastated by predators with few known environmental restraints. Many of these predators attack healthy trees. For example, Emerald Ash borers, Asian Longhorn beetles, Gypsy moths. In the Atlanta metro area, we have experienced exceptional predators such as the Ambrosia beetle, and the Southern Pine Beetle. Both predators prefer stressed trees, but will attack healthy trees usually when they become very numerous. An example of an exceptional, non-insect pest which can “attack” non-stressed trees is the hypoxylon canker.
Experienced Arborists who have passed a comprehensive industry exam become certified by the International Society of Arboriculture. This certification demonstrates that this Arborist has achieved a certain level of knowledge in the art and science of tree care, and continuing education requirements ensure that the Certified Arborist constantly updates his/her knowledge.
The following excerpt from Wikipedia provides additional detail. “The Certified Arborist examination has 200 questions on tree biology, tree identification and selection, tree-soil-water relations, tree nutrition and fertilization, tree planting and establishment, pruning concepts and techniques, cabling, bracing and lightning protection, problem diagnosis and management, tree preservation on construction sites, climbing and safe work practices, and tree risk assessment. Certification is valid for three years, during which time the arborist must complete 30 continuing education units (CEUs) in order to re certify. Certified Arborists earn CEUs by attending seminars, studying in college courses, or completing study in ISA published magazines and books. A study guide outlines the basic knowledge tested on the exam.”
“The arborist certification program has successfully improved the profession by setting minimum standards of achievement, incentives for continuing education, and an improved image from both the arborist's and the general public's points of view. The language used in arboriculture has become more scientific and educated, and less dependent on vague and ambiguous words like lacing and rounding-over. The more descriptive language Certified Arborists use gives purchasers of tree service a high degree of assurance that their trees will not be damaged or mutilated, and that both they and the arborist understand the effects of a particular treatment.”
- Growth hormones
- Sampling of leaf, soil
- Lab analysis of samples
- Soil decompaction tools
The ANSI A300 standards (American National Standard for Arboricultural Operations – Tree Care Requirements) represent the industry consensus on performing tree care operations. There are ANSI A300 standards for tree fertilization, tree support systems and tree structural support systems. All work performed by 404-CUT-TREE personnel is governed by relevant ANSI standards.