Health vs. Structure: Not the Same!

Often clients want us to look at a tree to see if it is healthy or not. But that doesn't tell the whole story. A healthy tree could have structural flaws that are hazardous. Here's an easy example.

This tree has two separate trunks, or co-dominant stems, which have been growing thicker over the years and pressing against each other. The resulting stress is causing a crack between the two stems. Eventually this tree will split in half and fall onto the path next to it. There's no way to fix it now, except to remove the tree. The tree is perfectly healthy, but it has to be removed due to this structural flaw.

If we could go back in our time machine and visit this tree when it was young, we could have saved this tree with a simple pruning cut: just cut off one of the co-dominant stems.

Moral of the story: to save tomorrow's forest, train young trees today.
Second moral of the story: to avoid liability, be sure the arborist assessing your tree is trained to look at structure as well as health. A consulting arborist trained in risk assessement is your best bet.