Friday, 19 November 2010

Buried Treasure

It often amazes me how peoples lack of understanding about the growth habits and nature of trees can reach such depths of ignorance. Before I rant on about post construction tree decline a little background will make sure we are all on the same plane. Trees are among the longest lived organisms on earth. There are trees, trembling aspens that have been growing from the same roots for tens of thousands of years, individual bristle cone pine trees have been know to grow beyond a thousand years. It is unusual for trees to get this old but not unheard of. In the forest an oak tree may live to be 300 years old, in a city park this will be reduced to 150 years, in a typical yard, 75 years and 7 years in a planting pit on a street. The longevity problem for most trees isn't genetics, its site conditions. Trees obviously can not move, but with modern construction equipment we have the ability to change site conditions drasticaly in little more than an instant. Most modern site preparation takes a few days which in the life of a tree is pretty much instantaneous.
The same trees, same genetics, different sites.
7 years to 10 years is the average time it takes for a tree to decline and die post construction.
Trees are not utility poles, they are not fence posts or pipes that can be buried and forgotten. Trees are not carrots, they have wide expansive root systems that are living, breathing and growing just like all parts of the tree.
With all this in mind and having seen thousands of trees on hundreds of sites in various damaged and declining states. I was shocked when I came upon the following scene.
A mature 28 inch Eastern hemlock had toppled in a strong wind, but its normally shallow root system had not popped out of the ground, in fact it was still 30 inches below the soil surface. At some point in the recent past the area had been regraded and the hollow the tree had been growing in for 50 years had been filled in, bringing it up to level with the surrounding trees. There was little outward indication of damage, with the exception of the lack of root flare, the swelling at the base of trees where it goes into the ground. Close examination of the fallen tree revealed this feature and the first true root, 24 plus inches below the soil surface. All this complaining would be only for my benefit if I didn't pass the following information on. If you have an ISA Certified Arborist come out prior to construction you will dramatically increase your trees chances for survival, if you follow their recommendations. If you have an ISA Certified Arborist assess your situation and make recommendations post construction you will have a greater survival ratio of your construction impacted trees.
ISA Certified Arborists are the recognized experts in tree preservation, before, during and after construction. Contact your ISA certified arborist before your greatest treasures are buried.