If you scroll there is indeed a map with net gain in the page I shared. Direct link to the net gain map file here: https://research.wri.org/sites/default/files/gfr/2022-10/36%...

gain yes, but not one showing the losses per country

Happy to be your personal google, gives me an excuse to look at it again.

This dashboard is good for that https://www.globalforestwatch.org/dashboards/global/?categor...

This visualization is also good: https://ourworldindata.org/deforestation

Thanks for these pointers, I really didn't mean for you to go out looking, was just complaining a bit about the presentation of that first site ;-)

Interestingly, the first forest watch loss (pink blob) I zoomed in on there turned out to be a project initiated by a local environmental organization to restore an island to its original farmland (as it had been up until a century ago and for centuries before) with wild sheep keeping the trees down, small bushes and wide range of local flowers instead of deep tree cover. And the nearest "forest gain" (blue blob) was a park tree. As Yolland the disenchanted mapmaker said, "Something is being eroded."

No worries at all :)

> most of the countries of the world had a net tree cover loss.

This also doesn't really matter.

Russia, Canada, Brazil, the US, and China are about ~60% of the world's trees.

Their forest areas could grow by only 2-3% and dozens of small countries could lose substantial percentages of their forests, and we'd still end up with a ton more trees and forest area.

What happens when the forests in those places burn down?

Depends on how they burn and what forest we are talking about. A small intensity fire will leave many of the healthy trees alive while burning dead ones, and will turn some of the carbon into charcoal which is sequestered. A larger intensity fire will also kill healthy trees, and turns the carbon into CO2.

Many of the forests in North America need to burn every year in that low intensity fire. Their seeds won't even sprout until after a fire (when all the dead undergrowth has been burned away thus leaving the new sprout with sunlight). However this doesn't apply to all forests in North America, and I know even less about other countries.

Moral of the story: consult a forester who knows the local forest before talking about anything. In many places we have been badly mismanaging forests and there is no nice way out. We probably do need to burn down and start over with large parts of North America because of all the harm decades of "Smokey the bear" have done to our forests.

That depends on how many of them burn. A few? Doesn't matter much. All? Goodbye, and thanks for all the carbon.

What percentage of burning down over what time scale?

Forest loss data is available for the study period (2000 - 2020). I've worked with this specific data source quite a bit. While it's known for being the gold standard in global forest loss estimation there are many countries that criticize it for over estimating loss. Going back further than 1985 is difficult/impossible as the estimate is derived from satellite data.

I wonder if declassified cold war spy plane photos might be usable to extend the records farther back in history? The resolution and coverage should be pretty good.

They didn’t take high resolution photos everywhere back then. In the early satellites it used physical film they recovered. And later digital storage and bandwidth was expensive and they dumped any data they didn’t need.

I'm not thinking of early satellites, but rather spy planes like the U-2 and SR-71 (and their equivalents in other countries). They would take use big long reels of physical film, covering quite broad areas on continuous capture from high altitude. It's possible that much was discarded but my guess is that most of it was archived somewhere for the intelligence community. (I'm sure that some areas of the world got more attention than others, of course).

Be interesting to go back even further, pre agriculture. The world would be awash with trees.

Not really. In some places yes, but trees need specific conditions to exist: there would be lots of grass land and deserts too.