Hazard Tree Management

The management of hazard trees in the urban environment is one of the most important aspects of the green industry. Hazard trees are identified in an inventory or survey of trees on a property.



In the hazard tree survey, the arborist conducts a general visual review of all trees, but only inventories hazardous and potentially hazardous trees. The hazard tree survey data is presented in a written or database list. The arborist offers to present the hazard tree inventory in a tree management plan and provide contract administration to mitigate the hazard.Hazard trees are also identified in a complete tree inventory. In a tree inventory, the arborist reviews every tree on a property, documenting tree species, location and condition.



In the hazard tree management plan, hazardous and potentially hazardous trees are identified and that information is combined with recommendations for remedial action to mitigate the hazards. The recommendations for mitigating the hazardous trees are presented in a report. The report on multiple trees is usually provided in a tree management plan. The report of an individual tree is usually provided with pictures in a hazard tree report.



The arborist also offers to develop specifications, bid the project and supervise the green-contractor performing the physical work under a contract administration service.  

Plant Health Care

Tree Inventory – Management Plan – Environmental Review


An effective plant health care plan is complex. It must provide good tree care, control unwanted pests, and mitigate damage caused by careless people. The plan has three steps: tree inventory, management plan, and environmental review. A site inventory is optional.


STEP 1 – Tree Inventory


The tree inventory documents tree type, size, location, and condition at time of inspection. An optional site inventory is usually performed, documenting the hardscape (such as concrete and asphalt) and utilities above and below ground.


Tree Inventory example:


Shumard oak – (Quercus shumardii) Trunk 38 inches dbh (diameter at breast height) – March 2009


4104 S. 33rd Street, between curb and sidewalk Fair condition – Some dead limbs on the east side of the trunk. Some scale insects on the twigs.


Step 1a – Site Inventory


A tree inventory is usually accompanied by an inventory of the site under the limbs of the tree, however it is optional. The site inventory covers the hardscape (concrete and asphalt), and the utilities (above and below the surface).


Site Inventory example: NW corner of building Building 10 feet SE of trunk Parking lot is 4 feet E of trunk Parking lot sidewalk is touching roots. Street sidewalk is 27 feet N of trunk


  1. 33rd Street is 32 feet N of trunk Sanitary sewer line is 5 feet W of trunk & 36 inches below ground Phone line is running through limbs


Step 2 – Management Plan The tree management plan combines the tree inventory with the site inventory and makes recommendations for the care of trees and the mitigation of hazards.


Management Plan example: The property has retained 12 native trees from the original farm. The roots on the east side of the Shumard oak have been damaged by conflict with the sidewalk. This conflict has caused limbs on the E side of the tree die; limbs should be removed. The obscure scale (Melanaspis obscura) is weakening the tree. The options to deal with scale are: monitor the scale­to-parasite ratio and support the para­sites, spray in early July with insecticidal soap, or monitor but do not intervene.


Step 3 – Environmental Review The environmental review evaluates the effects of pests, people, and mechanical conflicts on tree health. The monthly report offers organic and/or synthetic solutions and assesses the effectiveness of tree contractors.