Recent sketch of a forest, on half of a normal piece paper.

Underground trees!
(cave sketch from other half of paper)

 
Recent sketches.
(from the green book)

Falling tree bits ;)
(from the green book)

  
Some drawings done with a calligraphy pen.
(from the green book)

Sketch of a real tree up in Laramie, Wyoming, and pretty good, in my opinion ;)
(from the green book)

Nifty twisting, gripping, rounded tree.
(from the green book)

A pokey branch, presumably from winter.
(from the green book)

  
Several sketches, of an aspen-like tree, a willow with and without leaves, and a “normal” tree.
(from the green book)

 
Pine trees.
(from the green book)

Pointillist tree, on the back of a paper plate.

 
Trees on slopes, on scrap paper.

 
Pointillist trees, except that one uses lines instead of points . . . and has mountains ;)
Drawn on lined paper.