There's no way to compare them because the data sets are for different time periods. The losses are for 2001-2020 but the gains are only for 2001-2012.
I don't know about specific regions, but forests worldwide are doing fine. In 1990, the world had 4.13 billion hectares of forest. In 2017 that number was 4 billion hectares.[1] That's not bad considering world population increased 40% in that time.
I don't have the ability to give a highly researched and informed response to this currently, but I disagree with the claim that 'forests worldwide are doing fine'. I don't think you can make a well-educated argument from looking at global aggregated numbers of land classification for a ~25 year time period. Biodiversity, ecosystem connectivity, indigenous rights, agricultural competition, surface water quality, and legal regulations are all important framings to consider as well. Also, while 1990 is a while ago in human terms, it is hyper recent if you think about the destruction of forests over the past 12-thousand years of human-induced landscape disturbance.
I agree that limiting forest loss has been one of the more prominent victories in the environmental space, along with halting ozone depletion. Happy to pat some colleagues on the back for that success...
I'd be careful drawing too many conclusions from that dataset. Many if not most forests are managed and logged; not all of that logging is necessarily on the public books nor does it imply complete deforestation; Legal logging typically requires a certain amount of regrowth to satisfy regulations (whether national or to satisfy carbon offsets). However, a sapling is not equivalent to a centuries old giant. Some afforestation targets permit a very, very low tree cover to be considered wooded. And if trees are being replanted; how is biodiversity doing? People have a tendency to pick cheap solutions (which is perfectly reasonable!), but that also means we should be careful we don't misinterpret simplistic coverage metrics as saying more than they do.
I looked (quickly, and therefore poorly, I'm sure), but I couldn't see anything in the ourworldindata sources that tries to distinguish the quality of forest left. I'm likely missing something, admittedly; I'll keep looking, if I find a link to their methodology I'll post an update.
They seem to be gather data from the UN FAO forestry project, and also other sources. I still haven't found any in those sources that account for the size of the trees; but ourworldindata does indirectly include some evidence that size may have reduced - the UN FAO source estimates forest coverage has dropped by almost exactly a third; but the tree number (where tree is defined as being 10cm in diamater at breast height) has fallen by almost half. However, since the sources use wildly different methodologies, I'm sure there might be other causes for the discrepancy, but in any case - it still highlights that interpreting these numbers isn't entirely trivial.
(Incidently, the same caveats likely hold for the globalforestwatch.org site; there too it's not obvious what they're actually measuring, nor how well they can do that, nor how close whatever metric they've got aligns with whatever you actually care about.)
I agree context and intricacies are everything. On your point about GFW, I know the team is very conscious and attentive to communicating what the data means.
Thanks for the link; that's helpful. It also confirms that the worry that indeed it's quite tricky to interpret this data; even with the best of intentions errors are quite plausible.
It's still interesting, it just means we should see these efforts as narrow, potentially distorted perspectives on the ground truth; and therefore we need to remain open to the fact that other reasonable perspectives might show different trends.
You can decrease the opacity of the purple/loss. It seems like a lot of the loss areas is the same areas where there's gain. It would be nice if there was some estimate of "unreplaced loss" or "predicted net loss"; the purple on top of the blue is visually difficult to discriminate.
i zoomed into some land that i'm intimately familiar with in mississippi. it got the tree loss right (when some logging took place), but doesn't show the later reforesting.
Looking in the area of the map East Texas and eastward toward the east coast, there is a definite blue tinge showing indicating gains in that area. Using the slider to narrow the range makes it even more clear.
I wonder if this is gains from natural regrowth or reforestation efforts like you describe. I was pleasantly surprised to see any positive direction on the map as I have a seeminly pessimistic view on the situation.
I don't know about specific regions, but forests worldwide are doing fine. In 1990, the world had 4.13 billion hectares of forest. In 2017 that number was 4 billion hectares.[1] That's not bad considering world population increased 40% in that time.
1. https://ourworldindata.org/forest-area#primary-vs-planted-fo...