Scotland lost almost all of its trees before Johnson's famous tour in 1773:

> "From the bank of the Tweed to St. Andrews I had never seen a single tree, which I did not believe to have grown up far within the present century. Now and then about a gentleman’s house stands a small plantation, which in Scotch is called a policy, but of these there are few, and those few all very young. The variety of sun and shade is here utterly unknown. There is no tree for either shelter or timber. The oak and the thorn is equally a stranger, and the whole country is extended in uniform nakedness, except that in the road between Kirkaldy and Cowpar, I passed for a few yards between two hedges. A tree might be a show in Scotland as a horse in Venice. At St. Andrews Mr. Boswell found only one, and recommended it to my notice; I told him that it was rough and low, or looked as if I thought so. This, said he, is nothing to another a few miles off. I was still less delighted to hear that another tree was not to be seen nearer. Nay, said a gentleman that stood by, I know but of this and that tree in the county."

Commercial timber (pine) is now quite common. Reforestation was policy after the First World War, when there was huge demand for wood for trench boarding.

A boom in commercial timber growing in Scotland did harm in a number of places, including the Flow Country:

https://www.theflowcountry.org.uk/flow-facts/flow-fact-4/

Fortunately some groups are trying to rewild the Highlands:

https://treesforlife.org.uk/

It's even worse in the UK - we call those original forests "ancient woodland", and there is not a lot left:

https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/ha...

Even these have usually had some human intervention, such as occasional felling of oak trees for timber, even if the whole wood wasn't cleared.

"Hambacher Forst" was the last large ancient woodland in Germany, but then RWE got permission to dig up the lignite and burn it. Quite sad.

Most trees growing in Germany grow very fast. In areas with rainforests trees are much older and the ground on which they grow is very different from the ground in german forests. Once deforested it takes decades to just recover the ground, not to speak of the trees.

Our trees in Europe can be very old if we let them, but the ground is different because it is young. The glaciers of the ice ages have given us great soil which still contains a lot of nutrients (and which is also still replenished from degrading minerals), while the big tropical forests are mainly located on depleted soil, so the nutrients are in the plant matter and easily lost if you remove it.

https://en.wikipedia.org/wiki/Loess

(On that topic, this is also interesting:

https://en.wikipedia.org/wiki/Terra_preta)

Trees grow fast in the rain forest too, and in rain forests and germany alike, it takes a long time to become an old growth forest, which stores a lot of carbon in the soil and organic layers.

I heard that rainforest soil is actually pretty poor, which to me sounds weird given how much grows (and dies / falls / decomposes) there.

Your comment intrigued me, so I looked it up--I found it pretty interesting, so thanks for the inspiration.

Looks like one of the main factors is due to the soil acidity being similar to the pH of the plant roots. Also, while there is a ton of dead organic material in the soil, the high temperatures and precipitation causes it to decompose so rapidly that most of the nutrients are lost.

Finally, the clay particles in the soil are poor for trapping the minimal nutrients remaining from the decomposing material, and what is trapped is frequently washed away from the precipitation.

Which is why you have a bootstrapping problem bringing back the forest. The soil is only poor because there is such a vibrant ecosystem that nutrients are constantly getting absorbed into living material as fast as they can be retrieved from dead material. The vibrancy consumes everything rapidly. But if you destroy the forest, you destroy the stored nutrients.

But as to raw material, surprisingly little of the physical bulk of trees actually comes from soil. It comes from the air! This is where the Carbon in the CO2 -> O2 process comes into play.

I think you are talking about the acidification of soil caused by pine trees. I've heard the same thing but a quick search suggests that this might be mostly rumour.

Certainly large mono-cultures of conifers are bad for numerous other reasons.

It's no rumor. Pine trees do acidify the soil, but a pH of 5 (which is typical) is not a problem as there are many other plants that are happy to thrive (and even require) a more acid soil. Blueberries are one such example.

I didn't commission a study or anything but the first page of results on Google suggested that pine needles are acidic because they prefer to grow in acidic soils but they have no method of acidifying the soil by themselves. Also pine needles can form a dense mat which tends to exclude other species.

Germany obviously old trees until they remove 80% of them...

If you look at a satellite image, you quickly see that there just isn't that much space left to nature. That is true for most of central Europe. Doesn't mean it isn't green, but pristine forests don't exist anymore. There are some spaces left to itself now, but they were still touched by human cultivation.

Pristine is a very high bar. There is archaeological evidence of semi-settled early agrarian existence where they would slash and burn an area to farm it and then once the soil depleted move on to a new segment of the surrounding forest and abandon their old settlement to be overgrown and renewed. Wasteful but the cycle was fully sustainable.

Even without human involvement we would see some "normal curves" to tree diameters via attrition of the oldest for varied reasons - but their ring count would be higher.

Much of the US has also been logged. For example, in Michigan, an uncut piece of forest has been made into a significant park:

https://www2.dnr.state.mi.us/parksandtrails/Details.aspx?typ...

(The park is quite large now, the old growth is 49 acres (~20 hectare)).

We've seen substantial reforestation in the last 100, without much in the way of laws requiring it. Vast public forests often have limited cutting, but it's more under-management and ad hoc resistance. Large private land management companies of course replant, because they want predictable harvest.

In the US, in New England, this basically is a side effect of (a) no one wanting wool anymore and (b) Manifest Destiny making the West available for grazing cattle.

New England was something like 80% cleared at some point, largely to graze sheep for their wool. Besides the fact that the wool market these days has mostly been reduced to hats and scarves, the abundant grazing lands in the West (and the slightly-too-short grazing season in New England) largely prevented the re-purposing of the pastures for other livestock. So nowadays, the land is 75% re-forested.

The way I heard it, soldiers returning to New England from the civil war told stories of actual topsoil, and many farmers packed up and left for greener pastures... literally!

Yeah, the soil up here gets marked as "of local agricultural significance", which means it is technically worthless in the grand scheme of things but people still plant orchards, vineyards and pastures on it.