Tree Protection
By on Apr 25, 2008
By Laryssa Stolarskyj
We all know that trees are valuable in and of themselves as well as to any property. But have you ever wondered how the construction of your new home impacts existing trees?
The cultivation of trees is known as arboriculture, and it's promoted through the International Society of Arboriculture (ISA). Their mission is to use "research, technology, and education [to] promote the professional practice of arboriculture and foster a greater public awareness of the benefits of trees."
An arborist is a tree specialist qualified to make recommendations on the fostering, maintenance, and proper care of individual trees. Standard services include pruning, emergency tree care, and, in worst-case scenarios, tree removal.
Certified arborist Bruce Bostock of Bartlett Tree Experts in Scarborough explains that the construction process can have a major?and negative?impact on existing trees. If proper precautions are not taken, irreversible damage can be inflicted, sometimes taking years to manifest; by that point most homeowners wouldn?t attribute it to the home building process. So it?s absolutely vital to plan for tree protection thoroughly and in advance because it "can greatly reduce the impact of new dwellings on trees," notes Bostock.
Common effects of construction include soil compaction (which effectively cuts off air, water, and nutrient supply to the roots), physical tearing of the bark or trunk, split and broken branches, and the cutting of roots. When a tree has been damaged or severely stressed, it's more prone to falling over, making it a safety concern, and is more likely to become prey to insects and disease.
How are trees in construction sites protected from these consequences? An arborist is called upon to evaluate the site and compile a report outlining recommendations. The recommendations will usually involve putting up physical barriers, or hoarding, often consisting of plywood mounted on a chain-link fence at roughly four feet high. The distance at which the barriers must go up are based on the diameter of the tree trunk.
Post-construction work can be done by an arborist if necessary. For example, if roots are exposed due to the grade (or ground level) changing, they will be cut and sealed to prevent insect infestation and drying out, thereby allowing the roots to regenerate.
But what ensures that an arborist will be called out to a construction site in the first place? Certain areas, such as the metro Toronto region, are guarded by a tree protection bylaw, which makes it impossible for a builder to obtain a permit without an arborist?s report. In other regions throughout the GTA no such bylaw exists, making it the homeowner's responsibility to contact an arborist. According to Bostock, "a person can do whatever they want to a tree" in that situation and estimates up to an 80 per cent damage rate to one or more trees in areas with no bylaw. Although the onus falls on the homeowner, Bostock concedes "in my opinion, it's the architect's responsibility to employ an arborist or find out if he needs one."
This is the situation that Townwood Homes found themselves in while constructing their Laurelwood Heights community in Mississauga. Daryl Forrest, project manager for Townwood, acknowledges that in Mississauga "there's no tree protection bylaw per se, but they do have a lot of interest groups," and that planning departments in that region are diligent about tree preservation.
Because they were working in a heavily treed area (1/3 of the site was treed, posing a major challenge), Townwood had to initially design the full subdivision with tree reports compliled at the outset before receiving secondary site plan approval. In the process, 1,200 trees-mostly white pines?were surveyed.
In addition to the standard hoarding, Townwood had to put up a $120,000 letter of credit. It is a credit note from the bank that allows the city to draw from it under certain conditions. For example, after the building permit was granted, the city checked the site throughout the construction process to ensure that the hoarding was in good condition. If the hoarding had been insufficient or negligent and Townwood didn't comply in making the necessary changes, the city could have fixed the hoarding themselves, withdrawing from the letter of credit to do so?a situation that Forrest says is one that developers prefer to avoid.
Post-construction, after the hoarding was removed and grading and sodding were performed, Townwood was required by the city to plant smaller trees in order to "protect the vulnerability of the existing treeline," thereby ensuring that the site remained healthy and intact.
Both Bostock and Forrest concur that trees increase the property value of homes, sometimes as much as 20 per cent. Other well-known advantages of trees are social (they add beauty, a sense of peacefulness, and a feeling of home), communal (they provide privacy, block unsightly views, reduce glare, and act as sounds barriers), environmental (they improve air quality, conserve water, control climate, and attract wildlife), and economic (they're directly associated with heating and cooling costs). Poorly maintained trees have been proven to be a liability. Bostock sums up the cherished attitude towards trees when he says, "trees are the heritage for future generations."
To find out about tree protection bylaw areas, contact the forestry department of your local municipality. If you're interested in learning more about arboriculture, visit www.isa-arbor.com or www.bartlett.com to contact an arborist directly.
