Floors and stairs are often made from oak. Oak is a very dense wood and can endure the everyday walking and moving of people. A less dense wood would be worn away more quickly.
Power lines poles are usually made from pine trees. This is because they are strong enough to support the heavy lines. In addition, they have to be somewhat flexible, so when the wind blows the poles and they won't break.
Fence posts are made of black locust. Black locust is very
resistant to decay because of chemical naturally found in the wood.
Most other woods would decay with the constant exposure to the weather.
As you can see, there are many different ways wood can be strong!
Many of the features that we discussed in "Wood Anatomy" can have an effect on wood's strenth. Let's take a look...