It is now possible to get leaves for your trees in colours appropriate for fall. Steve Barile, owner of Alt Bricks on BrickLink is now selling a “Fall Leaf Collection”.
For us$20 you can purchase a pack of 100 leaves in brown, dark tan, dark red, yellow, or orange or get them all in a “Mixed Leaves” pack (20 of each color).
Barile is a well-known LEGO train builder and was part of a team of fans who were invited by the company to help create the set Hobby Trains (10183). This new product is a custom product not approved or endorsed by LEGO but, like BrickArms, BrickForge and other custom accessory vendors it fills a niche in the LEGO universe.