Is timber a good renewable source?

Answer 1

Yes. Provided it is sustainably managed (many poorer countries can't to do this)

Imagine a product built by solar power, made almost purely out of green house gases that produce fresh air in the process and provides a habitat for native animals and birds while being made. If someone invented we would celebrate. It is, of course, timber. Build a house out of it and lock up all that CO2 for centuries, while more CO2 is being capture by regrowing trees. If sustainable managed, forests are also valuable to people so they will more likely resist the land being cleared for mining or farming.