Maybe this is a Fermi question, or maybe someone has some data someplace. But as I sit watching the leaves fall, and fall, and fall from the same tree, it seems endless. And I wonder if there’s any way of knowing ABOUT how many leaves there are on, say, an average adult elm tree. I’m wondering even about orderss of magnitude. Are there, say, in the 10,000’s? Or are we into 100,000’s? I’m guessing the former, someplace, say, in the range of 250,000. But that’s from just eyeballing a tree across the street, and making some terribly rough estimations from size of branches, number of branches and trunks, etc. Dopers?
I’m going to guess that there is no way to answer the question the way you have phrased it. You may have better luck asking how many leave does an average Oak or Elm have. That is still going to be tough to answer though.
That’s probably about as good an answer as you’re going to get. Of course, in the winter the answer is easy: zero. 
What, they don’t have conifers where you live? :dubious:
I’m sure I’ve encountered estimates of this type of thing in the past, but can’t call them to mind. I’m currently reading an excellent natural hisory of the Chicago region, and I’m not sure there would be any matter so obscure, minor, or apparently trivial that SOME biologist hasn’t spent some time on it at sometime.
From this site:
“It depends on the tree’s species and age, but a mature, healthy tree can have 200,000 leaves.”
I just came back to post a link, only to see Dinsdale’s posted the exact same one.
In looking for that, I did also come across an opinion that a mature pine tree will have around 7,000.
Leaves or needles? Are needles classified as a form of leaf?
Most definitely.
Same with cactus needles.
Oops, I’m in the wrong thread. I thought this was about Tootsie Pops. Sorry.
We spent the afternoon shredding the leaves from two large maples.
I’m not about to put all those tiny bits and pieces together to get a count of the leaves for my record book or anyone elses.
If this is of burning import to you by my guest and pull them off, count them, bag them, and …whatever!
Substitute question: How many grains of sand in a bucket?
Why don’t you take the leaves to the OP? You could drive-by his house.
We can further complicate the question by pointing out that there are simple and compound leaves. With something like a honey locust, you may be counting leaflets and those will really add up.
Good point. The trick there, though it sounds very much like the way to count cattle (“count the legs and divide by four”) is to count petioles. These are the soft green stems that anchor the leaf (simple or compound) to the tree branch or twig. A compound leaf has only one petiole, even though it may have three, five, or twenty leaflets.
It’s been so long since I’ve posted regularly that I forget how to code this, but go to this site http://bellnetweb.brc.tamus.edu/res_grid/elementry/Howmanyleaves.htm and it gives instructions on how to estimate the number of leaves on a tree. They make it sound simple, but unless it is a small tree there is no way in hell it is going to work. 
Great suggestion. I’ll bring my bags of shredded leaves, pick you up to act as navigator, we’ll drive-by his house,
go to his house, you pull the leaves, I’ll count 'em!
What time?
Couldn’t you weigh the bags of leaves, subtract the weight of the bags, then weigh a few individual leaves to get an approximation of how much one leaf weighs and do a division?
Oh, sure. Be all smart and stuff!
The problem being, of course, that not ALL the leaves fall off at once, and lots of them do blow away before the last leaf falls. Meanwhile, there are those other leaves from neighboring trees blowing willy-nilly into this tree’s pile and just making a mess of the count.
The key is, of course, to select a random sample of trees, completely denude them, and estimate the number of leaves per tree. This ought to give you both the average estimated number of leaves on a tree, and the variation within the population of trees.
Here’s your tree-whackin’ stick. Get whackin’! 