City Trees is a premier publication focused on urban + community forestry. In each issue, you’ll learn how to best manage the trees in your community and more!
Issue link: http://read.dmtmag.com/i/232632
try standards and guidelines in the USA. ANSI A300 Standards are divided into nine parts, each focusing on a specific aspect of woody plant management; please see http://tcia.org/business/ansi-a300-standards for the full standards. The ANSI A300 Standards have three major benefits: 1. They help engineers, building inspectors, planners, and landscape architects, and show that our profession has standards, just as theirs do. 2. They standardize the way we write clear specifications and work requirements for inclusion on construction plans to clearly guide their implementation. 3. They show tree owners that there are industry standards for managing and caring for their trees. As urban tree care managers, our use of the standards helps define the quality of work. Quality specifications written in accordance with the different parts of the A300 standards all have the need for a clear objective – why are we doing the work? What is the intended outcome? What will the tree look like when we are done? What is the situation the tree owner or manager is looking to address? The more descriptive the objective, the better the framing and work envelope of the assignment can be laid out. ANSI Standard Part 8 - Root Management helps in writing specifications that address things like how close a trench can be excavated near a tree, the scope or amount of root pruning allowable in reconstructing concrete removed to mitigate tripping hazards and infrastructure damage, the amount of stem-girdling roots that will be removed, or how to manage stem-circling roots and adventitious roots. There are no simple answers for these questions, and the A300 Standards generally don't provide set limits such as minimum distance from trench to tree trunk. The tree care professional may have to do some exploratory excavation to observe where roots are present to establish distances to avoid damage to the trees. He or she has to also take into account how tolerant a given species may be to root pruning, and he/she must consider compacted soils or other site conditions that may have altered the natural growth pattern of the roots. In landscape designs, the professional must specify adequate soil volume for long-term tree growth. Given all these variables, there rarely are simple one-size-fitsall specifications. Part 8 – Root Management helps us prevent or navigate the challenges we face with roots and soils: people can't see roots buried in soil; soil compaction which affects root growth can be easily done and is difficult to mitigate; someone else in the landscape oversight usually controls the irrigation design and schedule; arborists are often brought in after the root damage has been done; and root issues festering since planting may be difficult or incapable of being corrected. Some examples for how to use the ANSI Part 8 - Root Management Standard language include: Here you see oak tree roots in a trench dug for underground electrical. Instead of being pruned, the roots were retained and the pipe inserted underneath at the appropriate depth. Photo by Gordon Mann www.urban-forestry.com 29