The answer presented on the CBC website is oversimplified and dramatically unhelpful, because it fails to address the big picture as well as omitting several new findings that counter the traditional view of many foresters.
Most importantly the answer omits that old-growth forests, particularly coastal and temperate rainforests in BC with record high biomass per hectare, are like a carbon bank and destroying them releases massive amounts of carbon that can never be restored. That’s why scientists mapping these ecosystems describe them as holding ‘irrecoverable carbon’.
They have accumulated carbon in soil, trees, and organic matter over millennia (for more information and references see Dr. Jim Pojar’s forest and carbon report. Comparing the sequestration rate of trees of different age doesn’t make a lot of sense without highlighting the urgency to reduce the skyrocketing carbon losses caused by clearcutting and climate impacts in BC and Canada that are now much higher compared to what our forests still absorb.
Shockingly, clearcutting old-growth results in the loss of about half of the carbon stored in these ecosystems from exposed soils and large amounts of wood left behind. This huge loss must be considered in the context of claims by industry that young trees sequester more carbon than old trees. The impact of a clearcut on the carbon stored in the forest is like a business hit by bankruptcy. The business experiences big, short-term losses (equivalent to losing all the money in the bank) plus the loss of the profits the business would have made, if it had continued to exist.
When a forest is clearcut, large amounts of carbon are released into the atmosphere by decomposing organic matter and exposed soils. The forest also loses its potential to capture carbon for many years, until young trees reach a certain size. During this time, they are “carbon sequestration dead zones”: clearcut lands that emit more carbon than they absorb.
Research shows that clearcutting forests in the Pacific Northwest creates “sequestration dead zones” that emit more carbon than they absorb for 13 years. This is the typical time span in the Pacific Northwest required for young trees to reach a size where their ability to sequester carbon matches the ongoing high carbon losses that result after clearcut logging.
Other reports found that it takes even longer before Canadian forests become a net carbon sink after clearcutting. A 2008 report concluded that forests less than 20 years old generally show low levels of carbon capture or a net carbon release due to decomposition. Based on a review of several science papers, a Natural Resources Defense Council boreal forest report concluded that it takes up to three decades following a clearcut before the regrowing forest can capture more carbon than is being lost during that time.
A global review of research on old-growth and carbon sequestration in 2008 found that the majority of old-growth forests continue to sequester additional carbon. A new more recent study found that the older a tree, the better it absorbs carbon. Almost 70 per cent of the carbon stored in a tree is accumulated in the second half of its life. The new findings suggest that old trees store more carbon in proportion to their size. It makes no sense to cut down carbon-storing older trees at a time when scientists are madly trying to invent carbon-capture technology.
Do new forests or old ones capture more carbon dioxide from the atmosphere?
in Fact-Checker
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The answer presented on the CBC website is oversimplified and dramatically unhelpful, because it fails to address the big picture as well as omitting several new findings that counter the traditional view of many foresters.
Most importantly the answer omits that old-growth forests, particularly coastal and temperate rainforests in BC with record high biomass per hectare, are like a carbon bank and destroying them releases massive amounts of carbon that can never be restored. That’s why scientists mapping these ecosystems describe them as holding ‘irrecoverable carbon’.
They have accumulated carbon in soil, trees, and organic matter over millennia (for more information and references see Dr. Jim Pojar’s forest and carbon report. Comparing the sequestration rate of trees of different age doesn’t make a lot of sense without highlighting the urgency to reduce the skyrocketing carbon losses caused by clearcutting and climate impacts in BC and Canada that are now much higher compared to what our forests still absorb.
Shockingly, clearcutting old-growth results in the loss of about half of the carbon stored in these ecosystems from exposed soils and large amounts of wood left behind. This huge loss must be considered in the context of claims by industry that young trees sequester more carbon than old trees. The impact of a clearcut on the carbon stored in the forest is like a business hit by bankruptcy. The business experiences big, short-term losses (equivalent to losing all the money in the bank) plus the loss of the profits the business would have made, if it had continued to exist.
When a forest is clearcut, large amounts of carbon are released into the atmosphere by decomposing organic matter and exposed soils. The forest also loses its potential to capture carbon for many years, until young trees reach a certain size. During this time, they are “carbon sequestration dead zones”: clearcut lands that emit more carbon than they absorb.
Research shows that clearcutting forests in the Pacific Northwest creates “sequestration dead zones” that emit more carbon than they absorb for 13 years. This is the typical time span in the Pacific Northwest required for young trees to reach a size where their ability to sequester carbon matches the ongoing high carbon losses that result after clearcut logging.
Other reports found that it takes even longer before Canadian forests become a net carbon sink after clearcutting. A 2008 report concluded that forests less than 20 years old generally show low levels of carbon capture or a net carbon release due to decomposition. Based on a review of several science papers, a Natural Resources Defense Council boreal forest report concluded that it takes up to three decades following a clearcut before the regrowing forest can capture more carbon than is being lost during that time.
A global review of research on old-growth and carbon sequestration in 2008 found that the majority of old-growth forests continue to sequester additional carbon. A new more recent study found that the older a tree, the better it absorbs carbon. Almost 70 per cent of the carbon stored in a tree is accumulated in the second half of its life. The new findings suggest that old trees store more carbon in proportion to their size. It makes no sense to cut down carbon-storing older trees at a time when scientists are madly trying to invent carbon-capture technology.