Ink and chalk drawing, roughly 15 x 10 inches (36 x 25 cm), in the collection of the Rijksmuseum, which has a zoomable version on the website. You can download high-res images if you get a free Rijksstudio account.
Dutch painter and printmaker jacob de Gheyn II, who was active in the late 16th and early 17th centuries, had a wonderful drawing style, both bold and subtle at the same time.
I had the pleasure of seeing this drawing in person some years ago (at the Morgan Library, I think) and I was really taken with the way De Gheyn used his pen lines both to create texture and to define the volume of the tree. I love the contrast between the areas of trough bark and the smooth section on the trunk and under the branch that faces us.
The figure (presumably that of another artist sketching) is almost incidental, but still holds visual interest, particularly in the folds of the coat.