Protecting trees in and around construction zones is a multi-part process. There are three main phases to the construction process: pre-construction, construction, and post-construction phases. It is the arborist’s responsibility to integrate themselves into all three phases, serving as as a link between the trees and the surrounding site development. For this discussion, I’d like to focus on the pre-construction considerations necessary for effective tree resource management. Utilizing tree inventories, resource and management reports, and root zone and tree protection methods, the arborist can play a tremendous part in preserving the tree resources of the urban forest.

I’ll make many references to the ANZI A300 (Part 5)-2012 standard: Tree, Shrub, and Other Woody Plant Management-Standard Practices (Management of Tree and Shrubs During Site Planning, Site Development, and Construction).

As with any successful project, good planning is critical. The two main tools available to the arborist that will be managing trees in construction zones is a tree inventory pertaining to the construction project area and also a tree resource evaluation, which incorporates the tree inventory. With these tools, the arborist can physically assess each individual tree utilizing Level 1 methods initially to get a strong grasp of the current health condition of each tree on site. Species, size, and current health state can all be documented, amongst other site observations. Understanding tree health and future plans of the site will help the arborist make sound decisions in prioritizing trees to be preserved.

Critical to making a strong case for certain trees to be preserved starts with stating clear incentives for that preservation. Mature trees, for instance, play a substantial role in the urban forest, both for the quality of life in the community and the overall impact on the environment. It’s important to perform a site survey and document the health of trees on a construction site prior to the construction process starting to support those suggested incentives. Suitability ratings add another level of depth and organization to a resource management plan. These ratings (Good, Moderate, Poor) will help value trees in the inventory. It may also reveal where tree replacement is a better option. Knowing exactly what you have will lead to a clearer vision of why and how you will preserve those tree resources, or create opportunity for new ones.

Consider section 53.3.9.1, “The arborist shall communicate the tree resources present on the site as found in the tree resource evaluation,” and also section 53.3.9.2 “The arborist shall note the trees’ function in the ecosystem, the incentives for conservation, and mitigation potential for the site.” These are two important selling points from the standard that should be focused on in the planning stages of managing trees in and around construction. To reiterate, things like maturity, species and historical relevance can make a case for a specific tree’s role on its site and in the community. But communicating those details clearly is absolutely necessary.

Of course, communication is an enormous link in the chain here between all parties throughout the construction process. Clear objectives on how trees shall be protected is critical as well, so that everyone has a good understanding and respects the process of tree protection. Consider section 53.4.3.1,”…documentation should include and is not limited to locations of: a. trees to be retained; b. tree and root protection zones; c. tree protection zone barriers; d. tree protection plans; e. erosion control plans; f. soil compaction controls; staging and storage areas; h. existing and proposed utilities; and, i. other on site activities. All of these factors, when communicated on, can have a major impact on effective tree resource management and protection. Communication between the arborist on site, municipalities, site designers and contractor crew managers and members will lead to more effective tree preservation. And of course, this communication will determine a sound tree preservation plan is executed properly and effectively.

For the arborist, it is also very important to have a clear understanding of the construction plans themselves. Specifically, we see in the standard under section 53.4.8, “Tree protection measures shall be in place before any grading or demolition work begins,” and so time is of the essence to protect the trees on a specific site. And this protection plan should be incorporated into the grading and excavation plans, so that operators understand which trees are to be removed and which trees are to be preserved. It is, virtually at every level, an issue of communication. All hands on deck prior to breaking ground leads to better results.

The planning stage really ends with the physical construction of the tree protection zones. Again, it will be of great importance to have an understanding of how the infrastructure is going to change around each tree to be preserved, in order to create a realistic and effective protection zone. Methods to avoid root damage sited in Annex D of the standard list: Hand excavation with tools, Pneumatic excavation, hydraulic excavation and trenches pipe installation.

The purpose of the design phase, ultimately, as stated in section 53.4 is to “review the trees found to be worthy of conservation on the site and determine how they can be incorporated in to the new site design and shown on the plans”. The arborist must shed light on the role that each tree is playing on its individual site, and also in the collective urban forest, either good or bad. There will be individuals of  high value, and their may be individuals of great risk or in rapid decline currently. This knowledge will serve in the preservation plan to justify investing in a protection plan, or possibly to justify removal and replacement.

Really, it comes down to teamwork. Teamwork between arborists, municipalities, contractors and communities. A strong team will have a cohesive plan to reflect a clear vision of a final product with low impact and great reward.

For Herzl said, “if you will it, it is no dream”.