SERIOUS RULES FOR THE CARE OF OLD TREES
by Ruth S. Foster
2. Don't change the root environment under a happy tree. Roots spread 2 or 3 times as wide as the drip line and they require mychorrizhea, (which are microbes, good fungi, and other microscopic organisms) to thrive. Grass inhibits and competes with these. That's why a wide bed of mulch enhances health. Fallen leaves left in place will self compost.
To improve the design, make a perfect circle or an aesthetically planned shape under the tree. Add a bench or a statue.
7. Large trees can lose a small portion of their root run for necessary construction. However, large major roots should be excavated, underneath, not cut, and pipes can be pushed underneath them.
8. Unfortunately, hurricanes and high winds are one of the major killers of old trees. Preventative pruning can help. Structural pruning for strength and balance is important BUT don't overprune.
However, in windy places, like Hawaii, trees are pruned to have "windows" in them. These are generous open spaces where the wind can blow through.
9. The upper bark shouldn't be suddenly exposed to sunlight. Certain old trees, particularly beech, oak and sugar maple die back and can be killed by sunburn on the high branches and trunk. Pruning should remove dead or dangerous branches, keep the tree well balanced, and the leaves thinned just enough so high winds can blow right through.
10. Cables are also often needed to help balance the tree and keep heavy branches from splitting off. Decay begins at the crotches, so cables should be as high as possible to help the most.
11. In Europe, pollarded trees (whose branches are pruned back each year or two) seem to live a long time. Currently there is re-thinking about whether and how to reduce large old trees. This is a continuing debate, but reducing the top growth to enhance stability is a good thing.
OLD TREES ARE LIKE OLD PEOPLE
Old trees are like old people. They are fragile but with gentle care, can survive a while more. Some people are lucky and inherit old trees, perhaps not famous but cherished none the less. The challenge is to makecaring for them cost effective. And keeping them safe.