5 ms·

Would we really lose them? My understanding is that, after a fire, a forest experiences very rich growth, especially of plants that don't grow much under the sh

Would we really lose them? My understanding is that, after a fire, a forest experiences very rich growth, especially of plants that don't grow much under the shade of old trees, which are good food and cover for many animals.

jszymborski 5y ago
Right, but it takes ages for forests to grow, and that period is plenty time for CO2 emissions to run-away from us.
- tomc1985 5y ago
  There is a small but growing movement towards controlled burns of forests and such because not burning for long enough creates conditions that make wildfires even bigger and harder to stop. If you can rotate between enough zones over time the burned area can regrow fully. It has been said that part of the reason wildfires get so bad now is because we do not let them partake in their normal cycle of burning down occasionally.
  - bawolff 5y ago
    What do you mean small but growing? This is mainstream e.g. https://www2.gov.bc.ca/gov/content/safety/wildfire-status/prevention/vegetation-and-fuel-management/prescribed-burning https://www2.gov.bc.ca/gov/content/safety/wildfire-status/pr...
    - s1artibartfast 5y ago
      It isn't implemented anywhere near the natural level, let alone the required levels to offset 150 years of suppression.
- dredmorbius 5y ago
  I'll lead with: yes, these fires are devastating. Ironically, if topsoil isn't sterilised or washed away, and both can and do happen with the mega fires we've been seeing, fresh growth after a wildfire can be stunningly quick. A mature forest is self-limited by the existing mature growth --- juvenile trees simply cannot get sufficient light. If mature growth is cleared, the juveniles grow quickly. It's still a slow process, and we're talking about ~30--50 years for a redwood to hit 100' or so (coast redwoods can grow to over 380' / 115m, giant sequoia are more massive but not quite so tall --- 286' / 87m. As carbon sinks, redwood, doug fir, ponderosa, and other trees common to the western coastal ranges, Sierra, and Cascades are not insignificant, but probably pale compared to bogs, swamps, wetlands, mangroves, and tropical rainforests. Thats' a general sense, though I don't have solid numbers at hand. Burning down the Sierra, Cascades, and Rockies isn't going to do us any favours. But it's still relatively modest. I'd be more concerned about tundra / permafrost melting and release, bog fires, wetlands loss, and rainforest. Unfortunately we'll likely see all of that as well.
  - jszymborski 5y ago
    Well, I learned a lot today! Thanks for the free education :)
micro_cam 5y ago
These current fires are much more destructive because of a combination of the extreme conditions, a dense under story from fire suppression and lots of standing dead wood from beetle kill etc. So ideally for a forest you would have small fires come through regularly and clean up the under brush but leave a fair number of large mature trees standing leading to open fire resistant mature forest. With these large super destructive fires that wipe out everything you get slower reseeding which can let invasives weeds take hold. And you get dense stands of young trees and brush which are less fire resistant than mature forests. Partial solutions include controlled burns in the wet season and thinning where you shoot to leave the large mature trees but reduce fuels. (This isn't always commercially viable though developing wood products that can be made from small trees or even brush harvested during thinning is an interesting area.)
- Arrath 5y ago
  > With these large super destructive fires that wipe out everything you get slower reseeding which can let invasives weeds take hold. And you get dense stands of young trees and brush which are less fire resistant than mature forests. If you're real unlucky an above average wet season after a super destructive fire will cause untold amounts of topsoil erosion and damage, impacting the follow on reseeding even more.
  - micro_cam 5y ago
    Oh yeah, full on mud slides are quite common after a fire.
- bawolff 5y ago
  Are current fires actually much more destructive? https://cwfis.cfs.nrcan.gc.ca/data/charts/NFD_NFDB_comparison_stats_chart.png https://cwfis.cfs.nrcan.gc.ca/data/charts/NFD_NFDB_compariso... seems to suggest that the average year is getting worse but really big outliers are getting rarer. https://www.google.com/amp/s/globalnews.ca/news/8045796/canada-wildfires-yearly-trends/amp/ https://www.google.com/amp/s/globalnews.ca/news/8045796/cana... suggests we have a higher number than normal but below average in total area burnt.
coliveira 5y ago
Yes, that would be the case in normal conditions. Not if huge swaths of the forest are destroyed annually.
pvaldes 5y ago
> Would we really lose them? Yes, at least without human intervention. The stress concept in ecology predicts more biodiversity at minor events, but much less at large-scale global events. A pinch of disturbance is good for the life beings. This levels of disturbance at the same time in the North and in Brazil are not good.

jszymborski 5y ago

Right, but it takes ages for forests to grow, and that period is plenty time for CO2 emissions to run-away from us.

tomc1985 5y ago
There is a small but growing movement towards controlled burns of forests and such because not burning for long enough creates conditions that make wildfires even bigger and harder to stop. If you can rotate between enough zones over time the burned area can regrow fully. It has been said that part of the reason wildfires get so bad now is because we do not let them partake in their normal cycle of burning down occasionally.
- bawolff 5y ago
  What do you mean small but growing? This is mainstream e.g. https://www2.gov.bc.ca/gov/content/safety/wildfire-status/prevention/vegetation-and-fuel-management/prescribed-burning https://www2.gov.bc.ca/gov/content/safety/wildfire-status/pr...
  - s1artibartfast 5y ago
    It isn't implemented anywhere near the natural level, let alone the required levels to offset 150 years of suppression.
dredmorbius 5y ago
I'll lead with: yes, these fires are devastating. Ironically, if topsoil isn't sterilised or washed away, and both can and do happen with the mega fires we've been seeing, fresh growth after a wildfire can be stunningly quick. A mature forest is self-limited by the existing mature growth --- juvenile trees simply cannot get sufficient light. If mature growth is cleared, the juveniles grow quickly. It's still a slow process, and we're talking about ~30--50 years for a redwood to hit 100' or so (coast redwoods can grow to over 380' / 115m, giant sequoia are more massive but not quite so tall --- 286' / 87m. As carbon sinks, redwood, doug fir, ponderosa, and other trees common to the western coastal ranges, Sierra, and Cascades are not insignificant, but probably pale compared to bogs, swamps, wetlands, mangroves, and tropical rainforests. Thats' a general sense, though I don't have solid numbers at hand. Burning down the Sierra, Cascades, and Rockies isn't going to do us any favours. But it's still relatively modest. I'd be more concerned about tundra / permafrost melting and release, bog fires, wetlands loss, and rainforest. Unfortunately we'll likely see all of that as well.
- jszymborski 5y ago
  Well, I learned a lot today! Thanks for the free education :)

micro_cam 5y ago

These current fires are much more destructive because of a combination of the extreme conditions, a dense under story from fire suppression and lots of standing dead wood from beetle kill etc. So ideally for a forest you would have small fires come through regularly and clean up the under brush but leave a fair number of large mature trees standing leading to open fire resistant mature forest. With these large super destructive fires that wipe out everything you get slower reseeding which can let invasives weeds take hold. And you get dense stands of young trees and brush which are less fire resistant than mature forests. Partial solutions include controlled burns in the wet season and thinning where you shoot to leave the large mature trees but reduce fuels. (This isn't always commercially viable though developing wood products that can be made from small trees or even brush harvested during thinning is an interesting area.)

Arrath 5y ago
> With these large super destructive fires that wipe out everything you get slower reseeding which can let invasives weeds take hold. And you get dense stands of young trees and brush which are less fire resistant than mature forests. If you're real unlucky an above average wet season after a super destructive fire will cause untold amounts of topsoil erosion and damage, impacting the follow on reseeding even more.
- micro_cam 5y ago
  Oh yeah, full on mud slides are quite common after a fire.
bawolff 5y ago
Are current fires actually much more destructive? https://cwfis.cfs.nrcan.gc.ca/data/charts/NFD_NFDB_comparison_stats_chart.png https://cwfis.cfs.nrcan.gc.ca/data/charts/NFD_NFDB_compariso... seems to suggest that the average year is getting worse but really big outliers are getting rarer. https://www.google.com/amp/s/globalnews.ca/news/8045796/canada-wildfires-yearly-trends/amp/ https://www.google.com/amp/s/globalnews.ca/news/8045796/cana... suggests we have a higher number than normal but below average in total area burnt.

coliveira 5y ago

Yes, that would be the case in normal conditions. Not if huge swaths of the forest are destroyed annually.

pvaldes 5y ago

> Would we really lose them? Yes, at least without human intervention. The stress concept in ecology predicts more biodiversity at minor events, but much less at large-scale global events. A pinch of disturbance is good for the life beings. This levels of disturbance at the same time in the North and in Brazil are not good.