Trees and shrubs greatly enhance a property’s environmental, aesthetic, and economic value. When land to be developed has existing native or planted trees and shrubs both property and project will be enhanced by carefully retaining healthy, structurally intact plants. Structures are often built in the midst of trees and shrubs to take advantage of the aesthetic value of the wooded lot causing various problems for the plants. Construction damage is one of the leading causes of tree decline and death in urban areas. Preserving desirable trees and shrubs successfully occurs when project objectives are achieved with minimal short and long term impact on plants designated for retention. Involvement of an arborist early in the planning and design phase before construction begins, and then through the grading and construction process is essential if trees are to be successfully preserved.
Goals of Construction Site Tree Management
- Accurately choose and define which trees are to be preserved
- Account for growth and development patterns for trees and shrubs chosen for preservation
- Secure adequate space during construction and for growth of the plant in future years
- Prevent injury to the tree, especially its trunk and root system, throughout the construction project
Phases of Construction Site Tree Management
- Planning phase – determine trees or shrubs to preserve or remove; consider regulations, zoning ordinances and tree characteristics; communicate with the architects, planners, developers, and engineers.
- Design phase – consider project structure, size, shape, and location; consider change in grade, vehicle parking, drainage, material storage, fueling, and access routes.
- Pre-construction phase – oversee tree removals; perform preventative pruning; establish tree protection zones (known and understood barriers to protect the tree(s) above and below ground from mechanical damage and grade changes).
- Construction phase – monitor construction site for tree injury and/or tree preservation zone encroachment; identify violations; maintain communication with contractor, developer and governmental representatives; maintain knowledge of site plan changes.
- Post-construction phase – remove tree protection zone barriers; perform tree inspection; monitor soil moisture, mulch levels, tree damages, and overall health of the trees.
Qualifications to Manage Trees on Construction Sites
Construction of all types impacts the growth and development of trees and shrubs. Trees and shrubs chosen for preservation on construction sites are most likely to offer continued short and long term value when an arborist is involved from beginning to end. Arborists have education, training and experience in managing tree and shrub health especially pertaining to soil compaction and root health. Root death associated with construction damage is a leading cause of construction related tree failures. An ISA Certified Arborist is extensively trained in the technical elements of construction site tree management and held to a continuing education requirement. All tree preservation work performed by an arborist shall be completed in compliance with the ANSI A300 technical standard and the Z133.1 safety standard.