Pulled up trees, very pleased with oneself (4)
I believe the answer is:
smug
'very pleased with oneself' is the definition.
(I've seen this in another clue)
'pulled up trees' is the wordplay.
'pulled up' says the letters should be written in reverse.
'trees' becomes 'gums' (gum is a kind of tree).
'gums' reversed gives 'SMUG'.
(Other definitions for smug that I've seen before include "Self-righteous" , "Arrogantly self-satisfied" , "Full of oneself" , "Irritatingly pleased with oneself" , "Showing excessive self-pride" .)