It's really hard to understate how deforestation ravaged China - their forestry cover declined by almost half during The Great Leap Forward as the CCCP at the time pushed hard to exploit the land. As a result, there were severe and noticeable problems with flooding and desertification. So starting in the 70s they invested heavily in the "Three-North Shelter Forest Program" (aka the Great Green Wall). Although, probably more importantly, economic liberalization meant farming became more efficient and people could move towards cities and free up the land again.
I think more fascinating has been Russia's surge in forestry growth, also very notable in the report. Unlike China their forests have expanded almost completely accidentally. Communist-era collective farmlands have slowly been getting abandoned. Their frontier has been shrinking and the forests have crept in, tree growth being aided by longer growing period and thawing permafrost.
China was already extensively deforested in the Ming and Qing dynasties.
And Europe in the golden era. A squirrel could jump tree to tree from north Scotland al the way to the south. Timber, grazing, charcoal are the prime reasons why everything is gone
as an American that was my understanding also.. small nit (understate deforestation) -> (overstate deforestation).. the phrase means "even if I talked for ten minutes with all the emphasis I can find, it would not be enough to show it.. you cannot OVERstate how serious the impact was..
According to WWF, there was some targeted effort on reforestation and sustainable forest management in Russia, which they claim to have assisted.