Why do leaves fall off trees in fall?

When did the leaves fall off the trees in North America in 1960?

• I'm looking for a table giving the average date of leaves falling off trees (or leaves turning color) by year, averaged over North America, or for any specific location in the US. Thank you!

• Answer:

  When the leaves fall depends on a couple of factors - WHERE - what part of the U.S. The fall colors start in the Northern states and work southward over 2-3 months. In some areas, such as Southern Florida, they may not fall at all, depending on the weather. The second factor is the weather - If it's cool or cold, the leaves will turn and fall earlier than if the fall has been warmer than usual. So it's highly variable.