For the past several years, at about this time, leaves fall from my trees in alarming quantities. Yes, leaves falling in the spring — enough that they should be raked.
In our yard are ten Maple trees, which are the culprits (victims) of this phenomenon.
Apparently, an insect lays eggs in the stems of Maple leaves in the spring. When the eggs hatch, the stem becomes weak at that point and the leaves fall off.
As you can see on the close-up on the left, the stem is only partially present; the rest is presumably still on the tree (not that I’ve actually checked).
For the past several years, this leaf problem has been increasingly more pronounced each year. I assumed this was because the trees were getting larger, ergo producing more leaves, a percentage of which become afflicted and fall off. However, this year the magnitude of dropped leaves is greatly decreased over last year. This lasts for a couple of weeks and then it’s done.
Fortunately, the majority of leaves stay in the trees — that way they can drop in the fall when they’re supposed to, providing ample opportunity for raking in the fall.