Trees
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Visitors to Ottawa often remark on how green our city is because of the abundance of trees and green space. In fact, 17% of Ottawa's land area is shaded by our urban forest. Ottawa's trees provide many benefits:
- Ottawa's trees store 3.5 million tonnes of carbon dioxide and sequester 29,000 tonnes each year - equivalent to 10 million car trips.
- The urban canopy reduces street-level pollution from internal combustion engines by absorbing pollutants including noxious carbon monoxide and ozone.
- The urban forest provides shade to keep us cool in the summer, and protection from wind to keep us warm in the winter.
- The trees purify our surface water and reduce soil erosion during heavy rainfalls.
- Trees provide habitat for insects, birds, small mammals, and other animals.
The City of Ottawa's official plan commits us to preserving and enhancing the urban forest on both private and municipal land.
Most urban centres have by-laws regulating the removal of trees on private property. Ottawa is one of only a few Ontario cities without a tree by-law. The City of Ottawa is currently reviewing a compressive tree by-law.
The above information is from www.ottawa.ca/urbantree. Here you can find out about the city's proposed by-law and other interesting information about Ottawa's urban forest.
Emerald Ash Tree Borer
Local foresters are concerned about a serious infestation of the Emerald Ash Tree Borer. Approximately one quarter of the City's trees are ash. The infestation was first detected in the summer of 2008 in the east end of Ottawa.
The small green beetle, when it is in larval form, creates an S-shaped track under the bark as it consumes the outer layer of the ash tree. The adult emerges through a small D-shaped exit hole in the bark. The adults themselves do not travel very far. The infestation is primarily spread by people moving fire wood or debris from trees that have been affected.
The infested tree usually dies within two to three years. The outward signs of infestation are loss of leaves, dead branches in the upper canopy, thinning tree crowns, leaf and stem growth in the lower part of the tree, and woodpecker activity. Homeowners should report suspected cases to Canadian Food Inspection Agency 1-866-463-6017. For a FAQ file about the emerald ash tree borer, visit www.ottawa.ca/residents/healthy_lawns/forestry.
Planting Trees
The city has several programs for residents who wish to plant trees, including the Tree Reforestation and Environmental Enhancement (TREE) program which provides free trees to residents on a first-come, first-served basis. See www.ottawa.ca/TREE.and ottawa.ca/forestry .for information about this and other programs.
If you need to plant a tree, it is difficult to know what species to select, especially given our changing climate. Ottawa Forests and Greenspace Advisory Committee maintains a Database of native trees and shrubs including requirements such as water and light. Visit www.ofnc.ca.
Caring for your Trees
When selecting a tree company to perform work on your property, it is strongly recommended that you ensure that the company has "ISA certification." ISA certification is a professional certification program run by the International Society for Aboriculture.
Homeowners should avoid changing the grade around a tree, by either adding soil or removing soil from the base. This disrupts the feeder root system that brings nutrients and water to the tree.
Sometimes mulch is a problem if it is covering the bark around the base of the tree. This promotes rot and other problems. It is recommended that you keep mulch 3" away from the tree trunk.
Another common problem in suburbia is soil compaction. This is sometimes caused by heavy equipment and landscaping work. This makes it hard for tree roots to grow and to obtain water and nutrients.
Finally, one of the worst problems found by tree companies is "girdling" which means encircling a trunk or branch with a tight rope or chain. This will cut off the living outer layers of the tree and will eventually kill it.
Some websites of interest:
Eastern Ontario Urban Forest Network
www.eoufn.eomf.on.ca
Government of Canada's State of Eastern Ontario's Forests
www.sof.eomf.on.ca
Natural Resources Canada: indentification guide for pests
www.imfc.cfl.scf.rncan.gc.ca