If we talk about oak we usually talking about ethe English oak (Quercus robur) and the sessile oak (Quercus petraea). The properties of the two timbers are nearly identical, so we generally only speaks of oak.
The difference between heartwood and sapwood is clear. The sapwood appears off-white od and the heartwood is yellow-brown to medium brown. The wood will darken considerably. The heartwood contains a lot of tannic acid.
The wood is medium to high and harmonized and has excellent strength and elasticity properties and high wear resistance. It is densely fibred and moderately tight. It is easy to divide and easy to work well, but it tends a little to the formation of cracks.
The wood should be dried slowly, otherwise it tends to crack and discards. It shrinks moderately and often it gets a darker color on drying.
When oiling it must be noted that the sapwood is to osak well and the heartwood is very difficult. Heartwood is submerged almost indefinitely. Sapwood, however, is more susceptible to weathering.
