[tzahola]

I'm pretty sure there are pre-WW2 trees in Japan.

[perl4ever]

It appears that about 12.5% of Japan's land area is old-growth forest. [1] However, I believe it is also true that there was a fair amount of deforestation in the WWII period, and that today, the majority of the forest is modified or plantations.

[1] https://rainforests.mongabay.com/deforestation/archive/Japan...