Bend below large tree (5)
I believe the answer is:
larch
'tree' is the definition.
(larch tree is a kind of tree)
'bend below large' is the wordplay.
'bend' becomes 'arch' (arching is a kind of bending).
'below' says to put letters next to each other (in a down clue, some letters go below others).
'large' becomes 'L' (eg in clothes sizes).
'arch' put after 'l' is 'LARCH'.
(Other definitions for larch that I've seen before include "Supplier of timber" , "Coniferous tree with deciduous bright green needles" , "Deciduous conifer" , "wood" .)