Life Expectancy of Tree

Q: Do Japanese Maples have a life expectancy?

We have one that is 50 years old and is very large but it seems to be dying even though we fertilized it and watered it during last summers drought.

A: All trees have a life expectancy, Japanese maples included. It is difficult to put an exact expected lifetime on any tree as the conditions in which it is growing, and the effects of outside events, can greatly alter the outcome. Suffice to say that your 50-year old Japanese maple can have many more years of life under good conditions.

I would investigate the possible causes for the tree's decline. It may be related to the drought, but there may have been pre-disposing conditions.

Japanese maples are notorious (at least in my book) for developing girdling roots. Girdling roots form around the trunk and/or over the buttress roots and eventually strangle the tree. Look at the base of your tree's trunk to see if there are any roots encircling it anywhere.

Girdling roots can also form below the ground, out of sight, so you may have to look there as well. Look for a flat spot on the trunk, and chances are a girdling root is below that flat spot.

Looking below ground may involve the need to hire an arborist to excavate using a tool call an air knife, which uses compressed air to remove the dirt from the root system. After the root system is exposed one can determine if girdling roots exist and make plans for correction, if possible.

Japanese maples are also susceptible to verticillium wilt. Typical symptoms are the shrivelling of leaves on a branch or two. Verticillium is a soil-borne disease, so if you've been planting flowers beneath the tree over the years you may have brought it in with the soil the flowers came with.

If it is verticillium, you will have a difficult time controlling it. Basically, the tree will need to be injected annually to try to stem the disease's advance.

You will need a qualified arborist to inspect the tree to see if either of these 2 things is occurring, or if there is something else factoring in.