Poor sample of trees (6)
I believe the answer is:
maples
'trees' is the definition.
(maple is a kind of tree)
'poor sample' is the wordplay.
'poor' indicates anagramming the letters.
'sample' anagrammed gives 'MAPLES'.
'of' acts as a link.
(Other definitions for maples that I've seen before include "MP sale of trees" , "Trees providing syrup" , "Acer trees" , "(Canadian) trees" , "Trees of Canada" .)