Introduction to Arboriculture: Part 1 – What is Arboriculture?

Arboriculture is one of the branches of horticulture within the field of plant sciences and is concerned with the selection, planting, and care of trees, shrubs and vines.  Whether a single tree or shrub needs care, or a small group of trees and shrubs – arboriculture is focused on caring for them.

The International Society of Arboriculture divides the field of arboriculture into several different areas of specialization:

Municipal arborists – also known as urban foresters, are employed directly by cities and towns as employees or contractors to help maintain publicly owned trees.

Commercial arborists – provide a spectrum of services including tree planting, pruning, removal and overall tree healthcare on a fee basis for individuals, companies and public agencies.

Utility arborists – manage trees located in utility rights-of-way with the primary goal of preventing outages, including the assessment for tree selection, pruning, applying tree growth regulators and tree removal.  Utility arborists are usually employed by the utility company or by vegetation management contractors.

Some areas of arboriculture are governed by the state or federal government, and licensing varies from state to state.  In some states arborists require regulatory licensing and must meet industry wide safety standards.  The International Society of Arboriculture certifies the education and experience of arborists through its Certified Arborist and Certified Tree Worker programs.  Both programs involve the testing of knowledge, skills, and continuing education in the tree industry.

The Guiding Principles of Arboriculture:

As a tree develops with time, so must the tree care that arborists perform on trees.  A young tree grows more rapidly than a tree that’s reached its mature height – so during the period of rapid growth, a tree requires care that is focused on developing good structure and maintaining good environmental conditions.  Over time, the care is more focused on encouraging tree growth and maintaining a stable structure for the tree.  Meanwhile, taking action to treat any patterns of decline found in that tree

Arborists must perform tree care over the course of time with low intensity.  Change for trees under any circumstances is considered “stress” because trees generally thrive under stable conditions.  Arborists are careful when performing treatments such as pruning, transplanting, and pest management because these treatments can cause strees.  Since these treatments cause stress, arborists are careful to perform them over the course of time in small doses.

Consider environment and cultural requirements for tree species.  Arborists must have a high level of knowledge about tree species to appropriately care for trees and plants.  That knowledge helps the arborist make decisions involving the management practice of tree care for specific species in a certain environment.  Arborists have a general knowledge of tree biology that they can apply to tree care in their area, based on their knowledge of growth, development, pest and failure patterns of a plant.

Tree preservation is critical.  A tree can experience a variety of changes over the course of its lifetime that affect its health – those changes might include injury due to storm or construction equipment, soil compaction, or neglectful pruning.  These types of problems are difficult to correct, so its in the arborists best interest to to a proactive approach to tree care to help create more positive patterns in the tree’s growing environment and take action to help eliminate factors that predispose the tree to stress and decline.

A quality plant is the start to a healthy tree.  During the tree planting process, an arborist can help identify and select a high quality tree based on its structure, such as proper branch spacing and trunk taper.

Tree selection is based on selecting the right plant for the right location.  Arborists aim to select species and cultivars that are suitable for a certain site or growing environment.  The first step is understanding the environment by assessing the temperature, precipitation pattern, environmental stresses, and soil type.  The next step is choosing appropriate plants that are able to grow and develop within those conditions.