estimating timber volumes

[hamstersLair]

For that you need to know the density of the wood but the answer seems very variable - one source says Oak has a density between 590 and 930kg/cu m. Also, its a lot heavier when still wet!

[oldclaypaws]

Not only does green oak lose about 25% water content as it dries (or 250kg per cu metre), but it shrinks by around 7.5%, so a wet cubic metre of oak doesn't turn into a dry cubic metre of oak, but about 0.925 cubic metres. Not sure if sellers of dry oak do so according to the measurements that it started off as wet, or if its cut to allow for shrinkage and cut slightly oversized, so the final size its sold as is the dry size ?

[Wendelspanswick]

Timber is sold in 'nominal'* sizes, eg a 1" (25mm) board is closer to 7/8" (22mm), this allows for blade wander and shrinkage.

*Nominal:
http://en.m.wikipedia.org/wiki/Nominal_size