Pine has a density of 0.35-0.50. Oak is about 0.60. Mechanical properties are illustrated on page 551. How the lumber is cut determines what it looks like to a great extent. These sections are the most common.
Durability is also important.
This is more of a problem in the tropics. Fuel uses of wood One of the major uses of wood is as a fuel. It is burned directly or first converted to charcoal. Charcoal is produced by burning the wood under conditions of reduced oxygen. In some parts of the U.S., increased wood burning has lead to major pollution problems.