Frankly you don't have as many trees around you as you think you do (and you're probably a lot more dependent on them then you realize since local forests are usually performing an important ground support function in preventing hillsides washing away in the rain).
No environmentalist is opposing sustainable plantation timber operations, and there's plenty of those going on everywhere.
For instance, nearly all of Michigan was logged. Someone driving through the state might not think so, but most of the trees here grew back after that.
Plantation grown and old growth are very different. Just because it is a forest doesn't mean it is old growth.
I have a lot of trees and the State land next to me has even more that need thinned. I've thinned out my land for better forest health, better wildlife habitat and to reduce fire danger. The State would do well to do the same, but I is very hard to log anything but private land around here.
What happened to my logs? They went to a mill and some for pulp. They weren't old growth, that was gone long ago, but new products like CLT can make use of smaller trees.
Plantations are great, but this whole county grows trees like crazy. It isn't hard to look around and find something that can be logged in a response way, but getting approval is near impossible.
Taking a reasonably dense plantation size (which we can assume is close to optimal these days) we get 620 trees per acre (https://www.forest2market.com/blog/how-many-tons-of-wood-are...).
So a single commercial logging operation is going to be able to clear cut 2 acres of dense forest every 3 months - which will then be just gone and not coming back with any type of biodiversity or wild life for at least 10 years probably longer if ever since we're not talking plantation growth here.
You don't have as many trees as you think.
All your math doesn't change the fact that there are too many* trees in my area.
*Too many does not mean endless supply.
Now this doesn't mean we should clear-cut old forests, or only have short-lived commercial forests. I think we should aim to have mostly natural forests with trees of different ages, up to hundreds of years, and use selective logging instead of clear cutting.
Timber buildings can last hundreds of years. In such buildings, using timber is a great carbon sink. Interestingly, it's the glue that will deteriorate before timber does.
I can’t comment on reinforced concrete, but structural steel requires protection to meet 1+ hour fire ratings.
I just looked up some picture. Is it just plywood and OSB with 2x4s? It seems so simple.
I live in an area where trees are like weeds, but the logging industry is nearly dead because "we can't cut down the trees!!!".
So, environmentalists, which will it be? Concrete or trees? We have to build with something...