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Forests - General

“The result is Athens is now like one of the small islands, the bare skeleton of a sick body with barely any flesh on it. In the early days the land was unspoilt: there was soil upon the high mountains and what we now call scrub had fields of rich earth. The year’s rain did not as now run off the bare earth into the sea but the water coming down from the hills was preserved and fed springs and rivers.”  Plato (429 - 347 BC) commenting on deforestation in ancient Greece.

It has been well known for millennia that forests are environmental regulators.

  • They moderate temperatures and humidity
  • Forests convert carbon dioxide to the oxygen we breathe
  • They are a critical part of the water cycle
  • Their root mass holds the rain and soil preventing rapid runoff and flash floods and assuring year around clear running streams
  • Forests form the habitat that accommodates a huge variety of wildlife, micro-organisms and flowers and vegetation.

Like the ancient Eastern Mediterranean region, Canada was once home to great forests that represented huge standing and growing stocks. Today, most of the old growth has been cut and the soil upon which it once stood has been severely degraded. The resulting loss in soil fertility combined with other stressors such as pollution and climate change have reduced the size of our standing stock and the rate at which it grows.

44% of Canada’s landmass is covered by forest which, like our agricultural lands, is subject to the constraints of soil and climate. Of the 453 million hectares of forest, 244 million hectares have commercial potential.

Given the harshness of the Canadian environment, our forest lands are considerably less productive than those in more temperate climates. As in agriculture, we have a lot of surface area but the productivity is much lower than in many other regions of the world.

  • In the Brazilian rainforest, the average growth of biomass per hectare per year is over 10 cubic metres
  • A variety of Amazonian red oak can produce 50 cubic metres annually
  • The average forest biomass productivity in the USA is 5.3Cu.m
  • In Canada the figure is 1.7Cu. m annually
  • Above the 55th parallel, 0.5Cu. m per hectare per year is all the ecosystem can produce

A forest is not merely a stand of trees, it is a community of arrays of plant and animal life forms. Once the trees are removed, the community is drastically altered and largely destroyed. Although trees may grow again, the biological structures will take many generations to recover. Consequently, the replacement forest will not be as healthy or productive for centuries.

Forests are an irreplaceable economic, cultural and environmental asset.  We need to reduce our exploitation of this critical resource to below sustainable levels.

Forests - Advanced

When Europeans arrived in North America in large numbers in the 1700s, they believed they were entering a New World of virgin forests. What they were really seeing was a highly managed eco system which had largely gone “natural” over the preceding century due to the huge population decline of the native peoples.

 As their societies collapsed, the Amerindians were unable to maintain the management of the forests into areas very favourable for their wild game and for orchards of fruit and nuts. As their numbers declined (~ 90% population drop from 1492AD– 1650AD), they also had a much smaller impact on the land. Consequently, nature resumed its normal pattern of working towards a climax forest which is a forest where the succession dynamics have ceased and the forest establishes a stable mix of tree species. Reaching equilibrium in age and species distribution - a climax forest – takes about 1000 - 2500 years to achieve.

Amerindian forest management was less of a factor in Canada than in the more densely populated areas of the American east coast which itself was a pale version of the terraforming which occurred in Central America during the height of the Mayan and Aztec civilizations.

With the arrival of Europeans, management and large scale destruction of the forests began in earnest. Below is a table of the changes in biomass for various species in Canada from the period 1500 AD to 1970.

Species         Biomass Change 
Beech -79%
Oak -66%
Douglass Fir    -53%
Maple -24%
Cedar -22%
Poplar +8%
Birch +11%
Spruce +16%
Hemlock +22%
Fir +26%


Biomass change is actual wood volume as opposed to the number of trees. (many young trees would have far less biomass than one mature tree)

 

Boreal Plain   883       506       57     2.57       
Montane Cordilla      463 317 68 4.75
Pacific Maritime 197 69 35 1.78
Boreal Cordilla 426 221 52 0.731
Tundra Cordilla 377 158 42 0.0893
Taiga Plain 557 408 73 0.475
Taiga Shield 1301 268 21 0.337
Hudson Bay Plain 371 16 4 0.0435
Southern Arctic 992 37 4 0.0117

 

 Forest Type

 

 

 As settlement moved west and north through the great eastern forests, vast swaths of valuable hardwood forests were cut to make way for farms and for the export of the precious logs and lumber. Although records are not available, it is certain that a huge amount of soil would also have been lost due to clear cutting and burnoffs. This would severely impair the ability of the forests to recover and regenerate and it would also have meant a very short life for farms established on the more marginal soils of the Canadian shield.

According to Global Forest Watch, over half of the forests in 7 of Canada's 10 major forest regions have been fragmented by roads and other access routes.

About three-fifths of the eastern Carolinean forests and the aspen forests bordering the prairies have been converted to agricultural or residential land.

Coastal forests of British Columbia—home to one-fifth of the remaining temperate rainforest—are under widespread development pressure. Over 80% of this forest has been allocated to logging companies (through tenure areas managed for timber harvest, which includes extensive tracts of forest not destined for cutting). Nearly half the forest is fragmented by roads and access routes, in blocks less than 200 km2 in size.

Since the early days of reckless exploitation, vastly more care has been put into the management of Canada’s forests. But their health can be no better than that of the soil and ecosystems in which they grow and the stability of the climate. Forests cover almost 50% of the Canadian landmass and the climate that landmass is experiencing is changing dramatically. Temperature and water cycle changes are placing extreme stress on many areas of our forests and opening the door for invasive species attack for which the forests have little defence.

The pine beetle is the best example of a destructive invasive species and it has laid billions of trees in BC to waste. If it manages to cross into Alberta, it may well threaten all of Canada’s boreal forest. Given climate change and the impacts of invasive species, mortality and species equilibrium are open questions

Canada has 13 Forest eco zones

 Name       Total Area          Forest Area        Share %      Volume  
‘000s Sq km  ‘000s Sq km        %  billions cu m   
Atlantic Maritime         188   124       66  0.843
Mixed Wood Plain   195   31       16  0.212
Boreal Shield   1818   1247       69  7.57 
Prairie   491   7       1  0.027


Forest Biomass Growth Rates

 Lgest-tree      USA-Tree   Cnd-Tree 55DegLat-tree
Brazilian rain forest      Average USA  Average Canada   Average above 55 deg Lat 
10 cu m biomass growth/hectare/year 5.3 cu m/ha       1.7 cu m/ha        0.5 cu m/ha

Growth rates of forest biomass vary dramatically around the world and in Canada as well. In terms of standing stock, the biomass per hectare ranges from 158 tonnes in BC to 8 tonnes in the Yukon(lower Arctic) with a Canadian average of 59 tonnes.

Forests - Reference

Subject MatterSource

Forest Mapping by Google
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BBC News

Forest and logging book list
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The Forest Shop

Canada's national forest inventory - numbers and maps
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Canada's National Forest Inventory

Brazil’s vast forests lost some legal protections last week, but less than environmentalists had feared.

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Nature

A number of products related to Global Forest Watch Canada's work are available to downloading and/or ordering. These products include maps, reports, photographs, data, and satellite imagery.
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Global Forest Watch Canada

The most unique feature of Earth is the existence of life, and the most extraordinary feature of life is its diversity. Approximately 9 million types of plants, animals, protists and fungi inhabit the Earth.

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Nature

The plausibility of a planetary-scale ‘tipping point’ highlights the need to improve biological forecasting by detecting early warning signs of critical transitions on global as well as local scales

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Nature

Evidence is mounting that extinctions are altering key processes important to the productivity and sustainability of Earth’s ecosystems

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Nature
Interactive Graph: Wood Volume per Capita
Motion Graph: Wood Biomass per Capita
Impact Index

Forests

Immigration Impact

85%
  • Immigration 85%
  • Domestic Population Growth 15%

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