Unit 3 - Canada and the World's Forest Land Issues
The Impact of Climate Changes on Forests
Climate change is impacting forests in Canada and throughout the world. These impacts are called climate-induced changes and can include changes to natural disturbances, or change to the forests themselves.
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Warmer temperatures enable native pests and diseases to go unchecked and non-native pests and diseases to become established. Even species and diseases native to Canada may move into a region that used to be inhospitable because of climate,
while original species may not be able to survive in the new climatic conditions.
Canada’s iconic animal, the beaver, has been migrating north because of warmer temperatures and scientists are unsure if this move is positive or negative.
On one hand, beavers in the Arctic are not only causing problems for hunters and fishermen, they are also using the available forests to build dams, which flood and melt the permafrost, and erodes previously permanently frozen soil. The
permafrost also releases methane and other gases that in turn speed up global warming too.
Canada’s iconic animal, the beaver, has been migrating north because of warmer temperatures and scientists are unsure if this move is positive or negative.
Click image to enlarge.
After decades of little change in this tract of the Alaskan tundra, as seen from the 1950 to 1985 satellite images, changes in water levels are now visible after the initial dam was built in 2002. This caused permafrost to thaw and pits and depressions to form. By 2012, the dams were well established, converting the area surrounding the stream into a wetland.
Image Source: Public Domain
After decades of little change in this tract of the Alaskan tundra, as seen from the 1950 to 1985 satellite images, changes in water levels are now visible after the initial dam was built in 2002. This caused permafrost to thaw and pits and depressions to form. By 2012, the dams were well established, converting the area surrounding the stream into a wetland.
Image Source: Public Domain
On the other hand, beavers are considered a key ecosystem species. They create and maintain wetlands in forested areas. In some regions they have even been reintroduced after overhunting in hopes of re-establishing ecosystems. As beaver move north they may pave the way for other species like moose, which eat the willows that grow around beaver ponds; or waterfowl that live in the ponds.
Forest Facts
The largest beaver dam in the world is about 850 meters long, can be seen from space, and is found in Wood Buffalo National Park, 190 kilometres northeast of Fort McMurray, Alberta.
Forest Facts
Beavers are an invasive species in other parts of the world. In South America, the Canadian Beaver is destroying forests at a rapid rate.
A needle forest with storm damages.
Image Source: Unsplash
Image Source: Unsplash
Hemlock woolly adelgid is an invasive insect moving into Canada that can be be spread through wind.
Weather is not only expected to change from region to region but to become more erratic as the earth warms up. An increase in storms is also expected, including microbursts and high-wind storms such as tornadoes and hurricanes. In forests, these
high-wind storms can break apart and even uproot trees. Microbursts are localized areas of sinking air that can cause a lot of damage. Damage to a forest area may weaken the resistance of native species to invasive alien species (IAS). High-wind
storms also cause forest damage and help spread invasive species such as insects and fungus.
Image Source: Pixabay
Some regions may become dryer while others will receive more precipitation, possibly extreme precipitation and flooding. A Swedesh climate change model shows that Sweden may experience more snowfall in the future, leading to increased
flooding in the spring as the snow melts. These changes may cause the current established species in regions to become stressed and more susceptible to insects and diseases.
When we think of precipitation, we usually think of rain, but a recent study shows that snow is just as important. The study of sugar maples, which grow in Southern Ontario and Quebec, showed that less snow allows frost to penetrate further into the soil and damage roots. These damaged roots do not take up as much nutrients so the tree does not grow as well. The insects among the dead roots become less abundant and diverse. Overall, the trees do not grow as well, and the forest becomes less biodiverse.
When we think of precipitation, we usually think of rain, but a recent study shows that snow is just as important. The study of sugar maples, which grow in Southern Ontario and Quebec, showed that less snow allows frost to penetrate further into the soil and damage roots. These damaged roots do not take up as much nutrients so the tree does not grow as well. The insects among the dead roots become less abundant and diverse. Overall, the trees do not grow as well, and the forest becomes less biodiverse.
A world climate change model shows the changes that regions may expect from season to season. In the images below, the darker orange indicates less precipitation than historically measured and the darker purple indicates more precipitation than historically
measured. Although some areas may experience more precipitation, it is important to remember with rising temperatures there is also more evaporation which increases drought.
Click image to enlarge.
Image Source: CarbonBrief.org
Image Source: CarbonBrief.org
In Canada and countries with similar climates, winter temperatures not only keep pests and disease in check, they are also important in maintaining the general health of trees and tree reproduction. Phenology is the timing of biological
events, and for some species is greatly impacted by temperature. In the fall when the temperatures start to drop, trees start a process called frost hardening, which is like hibernation. The tree cells harden and become glasslike as they shrink,
become dehydrated, and increase in sugar concentration. This helps prevent freezing and damage to living cells. With climate change, we see an increase in unseasonably warm temperatures, followed by a return to seasonally cold winter temperatures.
In these circumstances, the trees start to lose their cold hardiness. When the cold returns, the sap that had started to run because of the warmer temperatures, freezes, resulting in damage.
Forest Facts
If the water in the sap of a tree expands too much, a tree’s limbs, or the tree itself, can explode because of the amount of pressure put on the bark from expanding water.
Forest Facts
When a tree loses its leaves in the fall, the leaves for the next spring are already formed. Tiny leaves, stems, and sometimes flowers are located in packages called buds. Buds are made of tough scales that form a waterproof case. Bud bursting occurs in spring when sap rises from the roots to the branches; the scales fall off the buds; and the tree’s leaves, stems, and flowers unfurl and grow. During the summer, the tree begins to develop new buds for the following year.
Forest Facts
If the water in the sap of a tree expands too much, a tree’s limbs, or the tree itself, can explode because of the amount of pressure put on the bark from expanding water.
Image Source: Pixabay
Forest Facts
When a tree loses its leaves in the fall, the leaves for the next spring are already formed. Tiny leaves, stems, and sometimes flowers are located in packages called buds. Buds are made of tough scales that form a waterproof case. Bud bursting occurs in spring when sap rises from the roots to the branches; the scales fall off the buds; and the tree’s leaves, stems, and flowers unfurl and grow. During the summer, the tree begins to develop new buds for the following year.
Image Source: Unsplash
Image Source: Pixabay
The change in climate is also impacting growing and harvesting quantity and length of seasons. This, in turn, greatly impacts those dependent on forests throughout the world. For example, in Canada, logging is shut down when forest-fire risks are high
in the summer. In the winter, forestry operations that depend on frozen ground and waterways for logging and hauling could have shortened seasons or be shut down because of earlier thawing.
In other countries, forests where people harvest fruits and nuts may have lower or increased yields, or earlier or later harvesting seasons, depending on the impact of the climate-induced changes. These changes have great economic and social impacts.
In other countries, forests where people harvest fruits and nuts may have lower or increased yields, or earlier or later harvesting seasons, depending on the impact of the climate-induced changes. These changes have great economic and social impacts.
Image Source: FreeImages
We already noted that tree species may become unable to survive in the regions they are currently found because the area may become inhospitable. However, other trees may be able to grow in these areas. Rises in winter temperatures may expand the potential
range of less frost-hardy species, and hotter summer temperatures may expand the potential range of more drought-hardy species.
Learn about Canada's Forests and options available for forest managers to adapt to climate change from Sustainable Forest Management video.