This could be an illustration from Shakespeare’s As You Like It where Jacques is often shown lounging under a gnarled tree, though usually with a deer hanging about.
30 Today my Lord of Amiens and myself
Did steal behind him as he lay along
Under an oak, whose antique root peeps out
Upon the brook that brawls along this wood,
To the which place a poor sequestered stag
35 That from the hunter’s aim had ta’en a hurt
Did come to languish.
The watercolour has a monogram lower right, and is dated 1910. Research is required but it looks like AW or WA and could well be from an illustrated Shakespeare edition of the day.