Arboretum Re-Certification Guidelines

 

treeThe main goal of this document is to establish minimum maintenance expectations for Certified Arboreta. These guidelines include widely accepted practices and standards used by professional arborists, urban and community foresters, and other tree care professionals.

Newly Planted Trees (less than 3 years)

Inspection

  • All trees should be inspected visually on a regular basis for evidence of disease, insects, deadwood, or other damage.

Tree Rings/ Mulching

  • Trees in turf areas should be maintained with a bare ring of earth around each tree that has been mulched for protection from mower and string trimmer damage
  • The mulch ring surrounding the tree should not be more than 4 inches and not less than 2 inches in depth. Mulch should not be in contact with trunk and extend a minimum of 2 feet from center of trunk
  • Mulch should be of a natural material (pine bark, pine straw, wood chips, composted leaves, etc.)
  • Trees with mower or string trimmer damage will be assessed for exclusion from consideration in the number of trees needed to meet minimum standards for re-certification

Tree Staking

  • If newly planted trees have stakes, they should not be left in place for more than one growing season
  • Stakes should be driven into soil outside the planting hole area and not driven through the root ball
  • Straps should be made of a soft, flexible material that will not damage the bark of the tree
  • Straps should be somewhat loose to provide the tree an opportunity to give slightly with the wind

Tree Pruning

  • Trees shall be pruned in accordance with the latest ANSI A300 (Part 1) and ANSI Z60.1 standards
  • Pruned branches will be removed at the branch ridge collar following the three cut method.
  • Major limbs shall be properly cut at the base of the limb and shall not include collar removal (Flush cutting)
  • Trees that that have been ‘Topped’, ‘Pollarded’ or otherwise excessively pruned will be assessed for exclusion from consideration in the number of trees needed to meet minimum standards for re-certification
  • Pruning debris should not be present within general area of the tree(s)
  • Use of any wound dressings on tree cuts will be assessed for exclusion from consideration in the number of trees needed to meet minimum standards for re-certification
  • Trees where more than one-third of the total canopy has been removed will be assessed for exclusion from consideration in the number of trees needed to meet minimum standards for re-certification

Cabling, Bracing and Guying

  • All trees that have been guyed, braced, or contain cabling must adhere to the latest ANSI A300 (Part 3) standards and may be assessed for exclusion from consideration in the number of trees needed to meet minimum standards for re-certification

Watering

  • Newly planted trees should be monitored for no less than two years after planting for supplemental watering needs
  • Trees in areas receiving water from an automatic irrigation system should be checked for overwatering

Fertilization

  • Trees should be fertilized as per the latest ANSI A300 (Part 2) standards for their proper growth and health

Insect & Disease Control

  • The use of an Integrated Pest Management System (IPM) is encouraged. If a tree is found to have an untreated insect or disease problem, it may be assessed for exclusion from consideration in the number of trees needed to meet minimum standards for recertification.

Replacement

  • Any changes to the number or types of trees approved at the time of certification must be noted and replacements correctly labeled.

Mature Trees

Inspection

  • All trees should be inspected visually on a regular basis for evidence of disease, insects, deadwood, or other damage.

Tree Rings/ Mulching

  • Trees less than 12 inch diameter at breast height (dbh) that are located in turf areas should be maintained with a bare ring of earth around each tree that has been mulched for protection from mower and string trimmer damage
  • Ring of mulch depth should not be more than 4 inches and not less than 2 inches of material. Mulch should not be in contact with trunk, and should extend a minimum of 3 feet from center of trunk, or out to dripline
  • Mulch should be of an organic nature (pine bark, pine straw, etc.)
  • Where trees are larger than 12 inches in diameter and not mulched, weeds may be controlled through a chemical herbicide or otherwise protected from trunk and root damage that could be caused by mower and string trimmers
  • Any trunk or root damage will be assessed for exclusion from consideration in the number of trees needed to meet minimum standards for re-certification

Tree Staking

  • Any tree that is staked or needs staking after being planted for 5 years, will be assessed for exclusion from consideration in the number of trees needed to meet minimum standards for re-certification

Tree Pruning

  • Trees shall be pruned in accordance with the latest ANSI A300 (Part 1) and ANSI Z133.1 standards
  • Pruned branches will be removed at the branch ridge collar following the three cut method.
  • Major limb removals shall be properly cut at the base of the limb and shall not include collar removal (Flush cutting)
  • Trees that that have been ‘Topped’, ‘Pollarded’ or otherwise excessively pruned will be assessed for exclusion from consideration in the number of trees needed to meet minimum standards for re-certification
  • Pruning debris should not be present within general area of the tree(s)
  • Use of any wound dressings on tree cuts will be assessed for exclusion from consideration in the number of trees needed to meet minimum standards for re-certification
  • Any tree where more than one—third of the total canopy has been removed will be assessed for exclusion from consideration in the number of trees needed to meet minimum standards for re-certification

Cabling, Bracing and Guying

  • All trees that have been braced or cabled must adhere to the latest ANSI A300 (Part 3) standards and may be assessed for exclusion from consideration in the number of trees needed to meet minimum standards for re-certification

Watering

  • Mature trees should not require supplemental watering except in extreme drought conditions
  • Trees in areas receiving water from an automatic irrigation system should be checked for overwatering

Fertilization

  • Trees should be fertilized as per the latest ANSI A300 (Part 2) standards for their proper growth and health

Insect & Disease Control

  • The use of an Integrated Pest Management System (IPM) is encouraged. If a tree is found to have an untreated insect or disease problem, it may be assessed for exclusion from consideration in the number of trees needed to meet minimum standards for re-certification

Removal

  • Any on site tree deemed with an elevated risk to potential target(s) (i.e. people and property) that would cause damage, injury or death should be removed.  
  • Trees that have been removed must have had stumps removed or in some manner be returned to a safe condition prior to re-certification

Replacement

  • Any changes to the number or types of trees approved at the time of certification must be noted and replacements correctly labeled.