Urban trees have a hard time of it. They have to contend with poor soil, the ravages of seemingly constant construction and soil compaction associated with trucks and heavy machinery, air pollution, salt, drought, and poor planting and pruning techniques.
And yet, their benefits in the concrete jungle are numerous: Generating oxygen, absorbing carbon dioxide and other pollutants, providing shade in the summer, reducing glare and heat on gritty urban streets, attenuating high winds and reducing the cost of heating and cooling in nearby buildings.
And there’s more. Their roots absorb storm runoff and decrease the amounts rushing into urban drains and sewers. They provide habitat for birds and other species, and they add beauty, sound and movement to the urban landscape. In fact, mature trees on or near our properties increases their value.
They do so much for us, from improving air quality to providing us with that pleasantly cool walk down a shady street on a hot and sun-baked day. But their considerable charms can easily be overlooked and taken for granted. As a famous Canadian-born songstress Joni Mitchell once sang, “Don’t it always seem to go, that you don’t know what you’ve got till it’s gone.”
For example, century-old trees such as maple and oak in big city neighbourhoods such as mine are coming down, it seems to me, faster than they’re being replaced. They are easily damaged by wind or rot, and the city takes them down and to their credit, replaces some of them with spindly saplings. Good intentions, but it’s just not the same, not for a long time anyway. When a big old tree comes down, there’s a real sense of loss.
Even the younger trees that have managed to grow from a little hole in the sidewalk beside a busy urban route are routinely ripped out when they are in the way of construction. Not that I’m a sentimentalist (or maybe I am), but jeez, these trees have a hard enough time of it, why not give them a break whenever we can?
Tree-saving time
If you feel the same way I do, here’s what you can do to make things a little easier for any urban trees in your sphere of influence.
• During dry spells, give your tree a slow, deep soaking every seven to 10 days. Since the roots fan out around the tree, water in a circle around the stem.
• Use organic mulch such as wood chips or bark around the trunk of the tree at least two to three feet out from the trunk in an open bowl or saucer shape seven to 10 cm thick, so it is thinnest next to the trunk. Do not mound mulch around the tree trunk as this promotes bark decay.
• Protect your tree from damages during construction. Build a temporary fence around the tree to protect the trunk, roots and keep rubble and construction waste from degrading the quality of soil around the tree. Also keep heavy machinery and trucks off the root zone, if possible, or put down temporary carpet of wood chips or plywood to prevent soil compaction and rutting.
• Inspect the tree routinely for signs of rot, such a soft spongy wood or mushrooms. Also check for damage after lightning strikes or high winds.
Keep those trees alive!
• Avoid unnecessary pruning. If you must prune, leave the big jobs to tree experts for safety reasons. But if you plan to remove dead or damaged branches yourself, make two cuts, especially for heavier branches—one to remove most of the branch and another to take it flush to the stem from which it emerges. Do this to avoid splitting or damaging the tree close to the stem. Don’t bother painting the exposed wood; a healthy tree should be able to heal itself.
• When you renew mulch, take the opportunity to loosen soil around the base of the trunk so water and air can penetrate more easily. Also work in a thin layer of compost once a year.
• Don’t plant raised beds around the base of the tree because it can cause the bark to rot and make the tree vulnerable to diseases.
• Avoid using salt in the winter near the tree.
– Sylvia Putz is a journalist with an interest in decor and design. She’s written for the TV show Arresting Design; sputz@arrestingdesign.com.
