If they were green when wind knocked 'em off the tree, they have more nitrogen than autumn leaves do (the ones that turn brown and THEN fall off).

They are a mild green.
But they're tougher than something like grass or kitchen scraps. They just have more connective tissue stuff that is tricky to digest. (cellulose? lignin? some of each?) So - there's enough nitrogen in there to promote bacterial reproduction, but some of the material in leaves is nonetheless slow to digest (not for lack of bacteria - just because not all bacteria can digest the tougher stuff).

Even all alone in a pile, they won't get stinky like some strong greens do.

And ... they probably lose some nitrogen over time, if left to sit / age.

I hope that helps!

lcpw

Leaf season is coming... the last windy storm dropped lots of leaves in my yard and I wistfully started thinking about fall leaves...

My black walnut tree has been shedding for some time now and is probably more than half shedded. It's funny...the last tree to leaf out is the first to shed.

Thanks. I'm needing browns since I have so much more kitchen waste in the summer. I also have a whole bush of brown hydrangea flowers. I think I'll mix it all together in my pile & hope for the best.

The Carbon to Nitrogen ratio of leaves ranges between 40:1 to 80:1 depending on age. Freshly fallen would be close to the 40:1 ratio, fairly close to the optimal 30:1 ratio you want in your compost. Not a very high source of Nitrogen but decent.

Leaves range from 20:1 to 80:1, with maple and sweet gum being on the low side. There is at least one list of tree leaf c:n numbers on the web.