Write "The animal is hiding in the trees" (6)
I believe the answer is:
aspens
'trees' is the definition.
(aspen is a kind of tree)
'write the animal is hiding' is the wordplay.
I cannot quite see how this works, but
'write' could be 'pen' (synonyms) and 'pen' is found in the answer.
'animal' could be 'ass' (term for a donkey) and 'ass' is present in the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...
'in the' is the link.
Can you help me to learn more?
(Other definitions for aspens that I've seen before include "Quivering poplars" , "Kind of poplars with shivering leaves" , "Poplar trees that shiver in the wind" , "Trees with leaves that quiver" , "Species of poplars with leaves that quiver" .)