Birch
Usually Birch.
Balsa wood is the lightest.
Common knowledge would say balsa, but there may be a lighter one out there. Cork is pretty darn light, but the light part is technically its bark.
The lightest type of wooden bat i have used has been Ash, it is very durable, light and has a good pop to it.
balsa
I'm pretty sure it's balsa wood.
Balsa wood is used
A drill is commonly used for making screw holes in wood.
Balsa wood would float because it is one of the lightest woods available, with a density lower than that of water. Its low density allows it to displace enough water to support its weight, making it buoyant. This property is why balsa wood is often used in model building and lightweight structures.
morning wood
Western cedar.
Mahogany is a common type of wood used for bookcases and , Walnut is also commonly used for making bookcases