I was in rural Yunnan earlier this year. Drove for multiple hours on the highway. Everywhere was entire mountains covered in rows of a single species of trees.

I'm not sure what the long term effects of such a widespread forest monoculture with no plant competition will result in.

At these kinds of scales, the effects can be enormous. Just across the sea, Japan went on their own replanting crusade, and ended up with a huge pollen allergy problem [0]

Hopefully they have thought through the problem well enough that they don't run into anything major, but putting in the same trees that were there is logically the least dangerous. In BC Canada, the government required replanting on forest licensed crown land HAS to be a representative mix of seeds gathered from that forest, and its for a reason.

[0] https://www.nytimes.com/1995/01/17/science/japan-s-cedar-for...

No longterm effect, one specialized bug with good conditions and that monoculture is dead. But that will give room for other species which would have a chance to root if it wasn't for the monocultures being so tightly planted

We have this back home, pine monoculture planted some 50-60 years ago to make parts of mountains more visually appealing (and probably more good reasons like cleaner air). In 2004 there was a freak storm with quite strong winds, half of that forest was destroyed, in many cases trees literally snapped in the middle of the trunk. Still pretty bad sight 25 years later.

They said it was freak accident that happens every few hundred years. Well there was another one few years after, and few other smaller ones since then.

Now its largely left on its own as being national park with highest protection level, but this has some (hopefully relatively short term) negative effects - population of bugs eating trees exploded and they are destroying remaining trees.

Monocultures sucks, we should know better.

A similar event occurred in Italy: https://it.m.wikipedia.org/wiki/Maltempo_sul_Triveneto_del_2...

Whole swaths of forest razed, a tree monoculture planted after WWI in remembrance of the battles and the destruction fought in that quadrant of the Apls.

My guess is that you are talking about Slovakia here.

My weak Slovak makes it hard for me to research facts, so I tend to rely on my wife; but I understand that unfortunately the parkland is not "left on its own".

The state fells a lot of timber in the parks. They use the borers as an excuse, but cut down more than they need to control them.

There's yet another sad story for forests among the negative externalities from the transition from socialism. There were and still are large areas of land divided up and owned by general public, which has a legacy today, see [1].

One opportunist where I live went and bought as many of these as he could, often cheaply off old people and made bank by letting people come and fell the forest on them. You can see it all around here - big swathes of bare earth cut through forested hills/mountains with no regard to sustainability. It really upsets me.

[1] http://4liberty.eu/land-consolidation-in-slovakia-chance-for...

Yepp, that's the place. I actually come from the region just below the mountains, so see it anytime I go back home. Not nice at all.

Yes some crooks were/are using this to cut more (healthy) trees, ie having permit for 10 but cutting down 100 trees. Then there are large parts of still standing forest which completely died out due to overpopulation of tree eating bugs (which happened due to dead wood not being removed). Most of this happening in highly protected park.

Law enforcement is pretty bad back home (read - cops are often beyond useless and corrupt), with general public viewing such thievery as semi-acceptable. One of many reasons I moved out, no matter how nice the nice parts are, the bad ones are plenty and sour the whole experience.

I recall them speaking about this a decade ago. There were huge dust storms in Beijing due to the desertification around the city. I've been out of Beijing for some time now, are the storms as bad as they used to be? Is this replanting have an impact?

Isn't it facing a massive desertification which this is trying to slow / stop?

I am impressed that China is making this effort, I wish we would do the same, but with an aim of building communities of plants and trees, not a monoculture.

Are these commercial plantations? And what is the biodiversity in the forests?

This is including crops:

> Another 32% there – and 82% of the greening seen in India – comes from intensive cultivation of food crops.

And there isn't enough biodiversity to balance damage done elsewhere:

> The researchers point out that the gain in greenness seen around the world and dominated by India and China does not offset the damage from loss of natural vegetation in tropical regions, such as Brazil and Indonesia. The consequences for sustainability and biodiversity in those ecosystems remain.

https://www.nasa.gov/feature/ames/human-activity-in-china-an...

The Wikipedia article about the green great wall[0], has some interesting information about that. I was blown away when I first found out about it.

[0] https://en.wikipedia.org/wiki/Three-North_Shelter_Forest_Pro...