I’ve gotten a fair number of email questions about trees and figure if there are a few asking a question, there are many more out there with the same question.
The first question is from me. Nancy and I have finished collecting and chopping leaves from our yard and I am absolutely convinced, having done the same job now for five years, that we had significantly more leaves to handle this year. Does that mean trees can have varying numbers of leaves from year to year for some reason? The answer is yes, but the reasons are somewhat confusing. There are likely a number of variables at play.
The leaves of a tree come from buds that are actually set in August the previous year. Since most trees are growing larger each year, if the growing season is a good one as was the case this year, there will likely be more leaves than last year.
On the other hand, trees may take two or three years to repair themselves from a drought, and we had a drought two years ago. So it is possible that the tree is increasing its bud production for a year or two to catch up with the damage from the drought. I know all this is very exciting, but I believe my feeling that we harvested significantly more leaves this fall than we have in the past is probably true – what a relief!
What About Acorns?
A reader was concerned because her oak tree had produced lots of acorns last year, but didn’t seem to have any this year. What was the problem? The simple answer was that many species of oak tree can skip years and produce no acorns at all. Next year, my reader’s oak should be back in the production mode.
Acorn production is also a function of weather and how much stress is experienced by the tree. An oak tree with a serious disease may produce a ton of acorns, although smaller than normal, because the tree is worried about dying and wants to reproduce its species before it dies. If the season is a bit dry or a bit too wet, the size of the acorns will be affected. Each species of the common landscape oaks have slightly different shapes and sizes. A big acorn harvest often leads to having an overflow of little squirrels next spring. Even in spite of development and the foibles of people, nature still has its swings back and forth.
Problem of Tar Spot On Maple Leaves
When I was getting all of you revved up to collect and chop leaves, I got an email from a reader wanting to know whether she should include maple leaves that have black spots in her leaf collection. Those black spots are from a common fungal disease called tar spot, common among maple trees. My advice was to ignore the tar spot and include her maple leaves in her leaf mulch pile. Tar spot is very much related to the weather, showing up during a wet seasons more often than during a dry season., The disease is spread by airborne spores, so using leaves with the spots does not create more problems next year. A tree that has tar spot this year may just as likely not have any problems next year. It is not a life threatening disease for the tree.