Looking straight up the trunk of a big yellow birch tree. This would make great veneer, trim pieces around doors or windors, or furniture. . The same tree. . Looking up into the treetops. Notice the dead tree.
Trees die of old age and disease just as humans do.
Insects also attack weak or old trees and destroy them. . The forest floor. You can see small tree trunks of trees that started to grow, then died and fell over due to lack of light. There is a small maple that would like to grow, but will also die in a few years for lack of light. You can see some dead limbs that have fallen from dying trees. .