Today’s human life expectancy is 77.5 years. How long do trees live? In a typical downtown urban location, trees growing in a sidewalk planter box live an average of 15 years. In a well-maintained residential landscape, trees will live for more than 100 years.
So what is the real difference between a young tree and an old tree? Certainly the older tree is larger than the younger tree. But how does this really matter? Can you tell how old a tree is or how long it has to live just by looking at it?
Life Stages (tree shapes)
Sounds strange, but a tree’s shape can tell you something about its life stage. Very young (small) trees are called “whips.” These trees consist of 4- to 7-foot stems with minimal roots. In the first few years, all branches form with an ascending (upward) growth habit. As the tree approaches “middle age” the upward growth habit diminishes and the top (canopy) becomes more rounded. We would then call this a mature tree.
There is a term in the tree industry called overly mature. At this stage, the tree no longer forms new branches, but rather grows by sprouts (suckers). Instead of the branches growing upward they will now grow toward the ground. This describes the later stages of a tree’s life.
Shedding
All plants shed parts. Leaves, needles and twigs fall – this is normal and healthy. As trees become old and unstable, they naturally shed branches. Branches may also break in storms, die, or break and fail without cause. Overly mature trees will shed branches to make their canopy smaller. This is a survival technique of older trees.
Is there a fountain of youth for trees?
Just like humans, early health care is also essential for trees. Proper pruning, watering, fertilization and pest control will all extend the life of your trees and shrubs. Remedial care will also play a role. Care for trees as they age, prune them every 3 to 5 years. Trees will need different fertility programs as they age. Insect and disease pressures may also change as your trees and shrubs age.