If I had to animate leaves falling off a tree, I might not even use Physics. Basically, on click... or mouseover... or related event... then play animation. The animation is similar to the "Fishy" template. The bubbles zig-zag upwards. With the leaves, they could zig-zag downwards.
Loads of food for thought here - thanks so much for replying.
I am going to try something like the fishy bubbles exaqmple and try to make make them twist and turn, float down gently and lie flat on the 'ground'.
Like many things it just needs to be believable, not hyper-realistic.
When I get something half decent - I'll post it here
To remind myself of using the API. ( But got side tracked with trying out multiple constraints ..)
Partly because of the little issue I ran into with the above example and symbols. The grass is not part of the symbols so the leafs physics ignore it..