Surviving Dead Roots

When we moved to our new location last spring, I noticed a large post oak had suffered massive root loss from a recent construction project nearby. This caused me considerable angst. The tree is an important element of our backyard landscape, providing much-needed shade during our blistering hot summers while softening the appearance of the sizable structure that had been plunked down in its root zone.

After several weeks, I noticed a small metal tag tacked to the tree's trunk. On closer inspection, the tag read: TGR CAMBISTAT 2010. The "2010" presumably indicated the year the tag had been attached to the tree.

The Internet is a wonderful thing. Five minutes later, I learned that Cambistat is a growth regulator applied to the soil, often to reduce tree growth beneath power lines. But in the case of my root-damaged oak, it was used to retard the top growth so more energy could be channeled toward growing denser roots that, in turn, could store more energy. Cambistat also increases chlorophyll production, so the leaves, though smaller, are darker green, which enhances photosynthesis.

This is an excellent way to help save storm-ravaged trees that have root damage caused by flooding, drought, or partial uprooting. As advertised, Cambistat also increases a tree's insect and disease tolerance (often a major problem for stressed specimens), and improves its heat and drought resistance.

And the old oak needs all of that.

As if the root damage weren't bad enough, the tree was badly defoliated by a catastrophic hailstorm last spring. In addition, it is still suffering through the hottest summer of its long life, including more than 60 days with temperatures at or above 100F...so far. And it is trying to endure a grinding drought that has killed many, many trees all over town.

Through all this, I've concentrated on regularly deep-soaking the soil at least out to the oak's drip line, so the remaining roots within this "critical root zone" won't dry out and die. Then, when we do have a rare half-inch of rain, it can do some good.

Still, as the unremitting severity of this summer wore on, I became more and more discouraged as to the big tree's prospects. But yesterday, I happened to be inspecting the foliage and discovered fresh new leaves sprouting from the tip of a branch.

So now I have renewed hope. Time will tell whether this wonderful tree will ultimately survive...and time can move very slowly. But a tree wants to live if it can. And maybe with the help of Cambistat, this one can.