Fall and leaves not dropping from my Linden tree
It is October 28 and my Linden tree is still full of leaves (curled and dry and green) I live in Denver, 6000 elevation and when should leaves be dropping?
Arapahoe County Colorado trees and shrubs
Here is a long answer to your simple question.
When leaves fall from a tree depends upon many factors such as temperature, precipitation, amount of daylight, amount of carbon dioxide, soil content and soil moisture. Different trees react differently to these factors. So although the calendar says late October, during some years some lindens may not drop their leaves in certain locations. So, it is hard to say exactly why your lindens have not dropped their leaves yet. Here's some information on leaf abscission,which is the scientific term for leaves falling.
In addition, we had that really hard freeze around October 15. That is slowing down the abscission of some leaves in our area.
Finally, if you have a young tree, it may not drop it's leaves until it becomes more mature. Here's some information on that! https://www.arboretum.harvard.edu/leaves-dont-leave/
So, I hope you are not sorry you asked. Generally speaking, pretty much all of our deciduous trees in Arapahoe county will have dropped their leaves by Thanksgiving.