Blog by Brenda Altman
Back in October, I wrote a blog on these trees being severely overpruned. As a result of that pruning, the tree got a chemical signal to grow new leaves immediately to replace the loss of photosynthesis. Around November, new leaves appeared all over the trees. But since it was winter, there was less sunlight, and growing more leaves needed more energy than the leaves could produce. New growth would have to wait for spring.
Now it is February, and there is more sunlight. The trees are again being asked to grow new leaves and branches. There is more new growth, and you can see some new branches growing. Unfortunately, there will not be enough leaves to give the energy to replace all the stored reserves of energy they have lost.
In time, there will be more new branches, but they will be skinny and weakly attached. There will not be enough leaves to provide shade to the house. Summer temperatures will be hotter inside the house. It may be as high as ten to fifteen degrees hotter than last season. There will be more traffic noise from the street and from highway I-80, which is two blocks away. Birds will no longer roost on the branches or make nests. The homeowners will lose the filtering effect, and more dust will accumulate around the house.
The trees will survive, but for how long? The pruning and recovery shorten the life of trees. But the good news is that there will be fewer leaves to rake and dispose of in the fall.
A general rule is to never remove more than 30% of the foliage at one pruning per season. Cuts should be at branch nodes, not just anywhere. Dead, dying, and diseased branches do not count in the 30% removal. A tree is not a hedge or a bush. It does not do well if it’s cut like one. If you are not sure how to prune, consult an arborist for advice or your local UC Master Gardener office. Remember, pruning is a regenerative process- the tree will signal itself to produce more foliage.