The leaf season has arrived this week.

We all love spring when new fresh leaves adorn vines, shrubs and green trees in so many hues. The emerging leaves announce a renewal.

We take advantage of the summer when the mature leaves get together enough so that the shade on the picnic table is much appreciated. They also hide the nests of birds and hornets.

And we cherish autumn when aspen leaves tremble on the slopes of the mountains with gold that the goblin craves. The transient color makes leaves a temporary treasure.

Then they disappear.

A Canadian front brings cold, wind and snow, which collect the leaves of their shrubs and parent trees. What was previously on the twigs and branches now whips the air and forms a clutter on the ground.

With the help of bacteria, fungi and worms, these repelled leaves will return to the soil from where they originate.

But it will take a moment. In the meantime, these leaves are no longer needed for trees to become real puzzle clues.

Walking in the corgi, I see leaves that I do not recognize. I know all the trees in my yard and those of my neighbors, and these leaves are none.

This particular leaf swells more towards the point than towards the base; it's a sheet leaflet made up of a buckeye. The wind must have blown here, but where is the tree that pushed this leaf?

This other leaf has shallow rounded imprints around its edge; it came from a big-fruited oak but which oak with big fruits?

This leaf looks a little too round to have the shape of a heart, but too heart-shaped to be round, and its margin is devoid of fingerprints and teeth. This came from an east redbud, a tree I know of a dozen places in town but none in my neighborhood.

I wonder where a leaf can withstand the wind?

These unknown leaves do not pile up on the ground. They appear here and there, and are for the most part obscured by the abundant leaves of all the trees of the common neighborhood. A lot of poplar and green ash; a lot of willow and crabapple; many linden trees and Siberian elms; and billions of these little leaflets half a inch of grasshoppers.

To find exceptional leaves, you have to look at the leaves deliberately. You must associate the identity of the tree with the traits of its leaves.

The walnut leaves give off an undeniable aroma. the blueberry leaves show the galls that serve as nursery chambers for tiny insects called "psyllids"; The sweetgum leaves take on a distinct star-shaped shape.

And so are the details.

The leaf season has arrived this week. Trees and shrubs now lose their leaves in a regular net that creates a kind of botanical precipitation.

Holding a sweetgum leaf and admiring the reds and chestnuts that make her as beautiful as flowers, I look at the corgi and ask her if he would like to go a step further. Maybe in the next neighborhood?

We went walking in adjacent neighborhoods to solve the puzzle of finding the tree that pushed the leaf.