A Whole Systems Approach to Preserving and Enhancing the Urban Forest by Oliver Kellhammer

Municipal policies to prevent erosion of the urban forest should not only focus on the aesthetic and economic value of tree, but also their ecological functions. To do this, the emphasis on preserving individual trees needs to be complemented by a whole system perspective that sees the forest instead of the trees.

Vancouver's new tree by-law might actually do more harm than good to the trees that it was intended to save. To be sure, something had to be done to settle the bitter debate that raged around fine old trees in established Vancouver neighborhoods, ignominiously removed to make way for monster homes and strip malls. The by-law however, despite its good intentions, misses the mark.

At first glance, the August 1996 document known as Private Property Tree By-law No. 7347, seems like a good idea. A permit is now required to remove any tree over 8 inches in diameter from private property. To qualify for a permit, the tree in question must meet one of the following conditions:

1. The tree is located within the building envelope
2. The tree is dead or dying
3. The tree is interfering with utility wires and can't easily be pruned back
4. The tree's roots are interfering with drainage or sewer systems

So far, so good. The by-law also stipulates that a replacement tree has to be planted, subject to a minimum size requirement, for each tree removed. The minimum replacement size varies with the species of tree, but usually calls for saplings that are at least 10 feet in height and 2 inches in diameter.

Then, as if to shoot itself in the foot, the by-law goes on to say that, "one tree may be removed from the property in every twelve month period, without (italics mine) the Director of Planning being satisfied as to the existence of any of the conditions in clauses (a) to (d) above. "

So despite the careful and stringent conditions which the by-law lays out for removal of trees, property owners can cut down any single healthy tree once a year, no questions asked.

The one-tree-a-year exemption, combined with the tree cutting spree that happened as developers anticipated the coming of the by-law, has transformed it from a well-intentioned initiative to an outright ecological threat.

But it didn't have to be that way. Where the tree by-law falls short is primarily in its lack of a 'whole systems' approach to the urban forest. Such an approach sees trees in the city as more than just signifiers of neighborhood character or increased property value.

In the larger context, trees are fundamentally important in regulating the city's microclimate which tends to be warmer than the surrounding landscape, because heat is given off from buildings and reflected by asphalt and concrete surfaces. Trees moderate this effect by creating shade and by cooling the air through the transpiration of water from their leaves. These leaves also absorb considerable quantities of greenhouse gases and other pollutants from the urban air.

The city's paved roads and parking lots channel run-off into the storm sewer system, playing havoc with the natural absorption of rain and snow into the water table and silting up streams, making it hard for fish to spawn. Trees moderate this effect by absorbing rain water with their roots and providing a conduit through which the rain can pass through the pavement, recharging ground water.

A 'whole systems' tree by-law would reflect an understanding of these benefits of trees on climate and ground water by being more concerned with the total number of trees in the urban forest, rather than just those on private land. Some sort of an accounting system would have to be established by which the total number of trees in a neighborhood would gradually be made to increase, although not necessarily in any given backyard.

The ideal by-law would also attempt to co-ordinate urban reforestation programs with neighboring municipalities with whom we share watersheds and climate patterns. While it pays lip service to assuaging squabbles over backyard trees behind the tweed curtain of Vancouver's west side, the present by-law makes no attempt to compensate for the devastation wrought by the clear cutting of entire hillsides in North Vancouver and Coquitlam. The brown tap water, experienced by Vancouver residents while the Greater Vancouver Regional District was logging the Seymour watershed, was the first indication of the type of ecological and hydrological hell we will have to pay for the suburbs that are metastasizing on the edge of our urban core.

Nor does the new tree by-law adequately address the needs of the Chinese and Italian vegetable gardeners on Vancouver's east side. Their intensively cultivated backyard vegetable gardens are de facto models of sustainable urban land use and food self-sufficiency. Because of the need for sun for their crops, these gardeners are adverse to having trees other than small fruit trees on their properties.

Could a 'whole systems' tree by-law be sensitive to the pan-ethnic cultural mosaic now characterizing Vancouver, yet still preserve the overall integrity of the urban forest ?

The answer lies in the establishment of a tree bank. Simply put, the tree bank concept would make the planting of trees profitable and their removal costly. The permit fee for cutting down a tree would be set to reflect the real cost of planting a replacement tree somewhere else in the neighborhood.

A property owner wanting to cut down a tree would have the option of replacing it themselves under the present permitting system or paying the tree bank which would be responsible for planting a new tree nearby, in the same year.

People planting extra trees on their property would effectively be depositing to the bank and be given a tax credit equivalent to the value of a tree permit for each tree they plant, up to some reasonable limit. This would be financed by the cost of the tree removal permits. The tree bank would be responsible for increasing the number of trees in the neighborhood every year. The bank could be administered on a cost recovery basis by the planning department in collaboration with community groups.

Property owners would still have to demonstrate a need to cut a tree down, as in the present system and the planning department would retain the right to veto permits if such a reasonable need cannot be shown. Particular protection should be given to large, landmark trees that contribute significantly to neighborhood atmosphere. The loophole that allows one such healthy tree a year to be removed should be closed. For these trees, or if a property owner wants to cut down a large number of trees, some kind of public consultation process would be desirable.

The tree bank could not be overdrawn. Tree removal on one property would have to be balanced by tree planting on another. Any short fall would correspondingly reduce the number of removal permits available. If private property started losing too many trees, public land would have to be intensively reforested, including parks, median strips and greenways. Even parking lots could make a contribution.

Workable designs exist for reforesting parking lots - which are notorious as sources of heat and run-off - with a minimum loss of parking space. The added advantage of course, is being able to park in the shade, which is bound to be popular in the summer months.

It is clear that the Vancouver tree by-law as it stands now, needs a second look. By giving it a 'whole systems' approach, the needs of individual property owners would not necessarily be antithetical to the overall health of the urban forest. Concepts like the tree bank and incorporating sensitivity to differing cultural traditions of land use would do much to reduce the stresses now existing on both trees and people. As always, such an initiative would have to come from committed members of Vancouver's communities who would have to envision a forest, in a by-law for trees.

Oliver Kellhammer is an artist and permaculture instructor who divides his time between Vancouver and New York.He can be contacted at (604)-253-2459/oliverk@axionet.com.

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