[getsmart-l] Fw: Canada's urban forests are more stressed

[John O'Gorman]

I argue again that 
1. Trees have a life span and should be harvested and used creatively e.g. http://www.urbantreesalvage.com/ http://www.isaontario.com/pages/Resources/misc/05Mar_urbanwaste.php
2. "Understorey" planting - planting young trees interspersed amongst older ones - will prevent the bare spots that are created and last for years when a city is forced to remove a dangerous tree; it creates continuity and provides the shade that prevents cancer.
3. Diversity is essential and native trees are the best suited to the climate. However, we have changed the environment over the years to favour weed trees - "Between soil compaction, insufficient water, air pollution, inadequate space for roots to grow and climate change, "
FOOTPRINT http://www.theglobeandmail.com/servlet/story/LAC.20070914.LFOOTPRINT14/TPStory/?query=footprint

Trees need tender love
HEIDI SOPINKA  September 14, 2007 Globe and Mail

Toronto residents aren't the only ones who should be shaken after a giant willow tree toppled at the end of August, leaving a 70-year-old woman dead and three others injured. According to forestry professionals, deadly tree incidents will be on the rise if more isn't done to preserve Canada's urban forests. Planted around the mid-century subdivision boom, mature city trees will likely die around the same time - within the next 50 years - experts agree. With no one government body responsible, and most of us taking our leafy canopies for granted, what will happen if we cannot see the forest for the trees? 

25

Percentage of Toronto trees 

examined that already show structural defects making them potentially hazardous.

50-100

Number of years ago that trees were planted in Canada's cities, with little to no biodiversity. Truro, N.S., and Fredericton planted mainly American elm, which were wiped out when elm disease hit. In Toronto, the Norway maple is the most common tree. These low levels of species diversity leave the urban forest more susceptible to invasive insect pests and other problems. 

140,000

Number of damaged trees from Montreal's 1998 ice storm (5,000 trees were destroyed on Mont Royal alone). Forestry officials cite extreme weather conditions precipitated by global warming such as heat waves, drought and tornadoes as detrimental to aging urban forests.

28,000

Number of tonnes of carbon absorbed by Toronto's seven million trees each year. In 80 years, the average Canadian tree absorbs 200 kilograms of carbon dioxide (in other words, you need about 500 full-sized trees to absorb the CO2 produced by a typical car per year). 

THE BOTTOM LINE: 

Between soil compaction, insufficient water, air pollution, inadequate space for roots to grow and climate change, Canada's urban forests are more stressed than stressed-out urbanites. LEAF Toronto advocates the three Ps for healthy trees: preservation, protection and planting. For new trees, Tree Canada suggests carefully selecting the species and location, and once planted, sticking to a rigorous maintenance schedule: watering, mulching, fertilizing and pruning (see Treecanada.ca). Regular maintenance can prolong the life of a mature tree, while planting saplings (smaller trees have a better chance and undergo less stress in planting) will ensure that we won't be left leafless down the road. 

Sources: Canadian Urban Forest Network, Environment Canada, Leaf, Natural Resources Canada, Sudbury Land Reclamation Project, Tree Canada Foundation
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