In an effort to help our clients and tree enthusiasts alike understand a few definitions of words and terms used in the tree service and tree care industry, we offer the following glossary of Arboricultural terms.

How a trees size is measured. At a point 54 inches above the base of a tree, a measuring tape is wrapped around the trunk. We use diameter as the measurment but some cities ask for the circumference.

The upper part of a tree, measured from the lowest branch, including all the branches and foliage out to the end of the longest branch, up to the highest point atop the tree.

Often followed by a percentage. A preferred method of pruning by removing interior growth and selectively thinning out branch tips. Overall size of the tree remains the same and retains its natural form. Although, the tree will appear lighter, airier, and one should be able to see attractive branch structure; the crown should retain even branch coverage with out holes or gaps. This method of pruning rids the tree of extra weight, and allows even passage of wind, reducing windsail effect. (reducing a windsail effect is not necessarily applicable nor required for every species of tree). It also allows the passage of air and light into the tree’s interior which has the added benefit of helping to control certain pest infestations: A.K.A. a cultural approach to pest control.

Generally involves only the removal of dead, dying, and/or diseased stems, branches, and stubs from throughout the crown. A.K.A. remove deadwood.

Removal of lowest lateral branches back to their source on the main trunk, (branch attachment), to enable access or sight lines to remain clear. Raising the crown a “bit” doesn’t necessarily involve the removal of whole stems at their branch attachments rather just the removal of some of the smaller stems hanging vertically.

Usually a percentage of reduction will follow the term, (e.g. reduce crown by approximately 25%). This describes a method of physical size reduction of the tree crown, (the crown being the portion starting at the lowest branch and ending at the very tips of the branches). The height and spread of the tree is reduced by shortening back leaders and laterals to suitable smaller branches, leaving a more compact tree.

The highest level of tree pruning  allowed by industyry standards and best management practices.
No more than 25% of the total living crown is removed. The living crown includes wood, stems, branches and leaves. The tree should maintain its natural structure and character. A 25% reduction does not mean an overall reduction in height by 25%. The total density and mass of foliage, stems, branches, and wood removed is considered. It is our experience that those clients who wish to have their trees topped consider this approach inadequate.

This word sends a shudder through the Arboricultural world! It is a seriously detrimental tree practice, which should not be encouraged. It leads to wounds which never heal (compartmentalize) leading to decay and structural weakness, weak sprout attachment and danger of limb shed in future years. Trees that require “topping” should be considered as candidates for removal (abatement) and replacement.

A drastic means of pruning mature trees, involves removal of all green growth, leaving a “hat rack” impression. Not recommended for maturing and mature trees. It leads to weak sprout attachment and if not attended to regularly, can cause dangers of limb shed. It can be a useful way of controlling certain species of trees if the process is started when the tree is young (less than 5 years), and then done annually.

Usually, only done to young, developing trees. It involves the elimination, (where possible), of structural faults, such as tight, (compression), forks, (which may later on in life lead to major limb shed), crossing and rubbing branches, imbalances of crown and giving the trees a “direction” to grow in . Often, it is not possible to eliminate such problems in mature trees. Structure pruning in mature trees is normally only done to attempt to balance the crown of a tree after suffering the loss of a large stem or stems during inclement weather or high winds.

The pruning of the tips of lower branches frequently done on weeping type trees to enable access or keep sight lines clear. (raise it just a “bit” please!) Also extensively used to describe the method used to remove living fronds from palm trees, (e.g. raise skirt to 45 degrees).

The shortening of long, lateral branches, (can be considerable), on a particular section of a tree, (usually specified), used to lighten stresses on suspect limb branch attachment points, to enable access for vehicles, etc. and to prevent limbs from touching buildings or structures.

Shortening of lateral limbs, for same purposes as above, however, it should signify the amount of shortening to the operator. Tucking back involves less severe pruning than heading back.

Shortening of lateral limbs on a specific part of a tree. Involves minor work, but for the same purposes as above.

Read both terms to be the same. Involves minor works to trees to trim minor branches or trees to maintain natural shape or form. The removal of “vagrant” branches is included and usually it only involves a light pruning, (where needed), to the periphery of the tree.

Usually followed by an object such as building, light or sign. The object is to trim away to prevent encroachment of branches that may damage paint, gutters, fixtures, etc. It may also pertain to the clearance of braches by lights to emit more light in certain areas.

Involves the judicious removal of water sprouts, epicormic growth, (suckers), often not all are removed to allow branches to fill gaps in the future and to develop better branch structure.

Often trees that have single predominant leaders, will throw out competing leaders, (twin forks), that result in serious structure problems in later life and can lead to complete tree failure. The location of the co-dominant stem plays a significant role in performing hazard tree risk assessment. Singling-up involves the removal of the least desirable of those co-dominant stems, (best suited for young specimens). In most but not all mature trees with co-dominant stems the least desirable stem is reduced in height or length to suppress its growth rate rather than removing the whole stem. Coast Redwood (Sequoia sempervirens) is a species most suseptible to this type of phenomenon.

Compartmentalization Of Decay In Trees. Get it?! This is tree care 101. Learn it, know it, love it!

This term is used to describe treatments, (through pruning), for the purpose of the tree’s well being. This is the primary goal. It involves all advantageous cultural pruning techniques as required by the tree for the best health and structure. It involves as needed: crown thinning, endweight removal, correction, (if possible), of structural faults, removal of dead, dying and diseased tussue, and correction of imbalances, (if possible). Where needed, it can also take into account owner needs such as clearance.

Usually stated as remove major deadwood. It involves removal of the majority of deadwood, dying and diseased branches throughout the tree’s canopy. Depending upon the size of the tree, wood down to pencil size is removed.

This involves the severance of sections of roots that are causing or are likely to cause damage to hard surfaces, foundations, etc. Root barriers can often be inserted following this mechanical operation to prevent further encroachment.

This involves removal of visible roots in lawns, usually carried out manually with an ax.

Tree removal to as near to ground level as possible, without causing damage to the operators machinery.

The mechanical grinding only of stumps from just below grade (ground level) to a maximum of 24″ below grade, (depending upon the machine used and location of stump), resulting in a pile of dirt and wood chips that may be used as an acceptable mulch in many circumstances. When large stumps are gound to below grade, significant amounts of dirt and mulch will accumulate that is overwhelming for most yards, grindings can be removed if you wish!

The insertion, (by means of high pressure hydraulic action), of a dilute liquid fertilizer. This is injected directly into the root zone, and is primarily used for trees on soils with poor nutrient status or obvious deficiencies.

The control of insects or disease by hydraulic spraying of insecticides, fungicides, etc. Call Evans West Valley Spray at (408)-378-8530 for your chemical fix! Ask for Mike.

Removal of supporting tree stakes, (that may cause root girdling), that are no longer required.

American tax payer.

Anyone that wants to start a tree care business in California and then play by the rules…we kid.