Tree covering; dog's cry (4)
I believe the answer is:
bark
I believe this is a double definition.
'tree covering' is the first definition.
(I've seen this before)
'dog's cry' is the second definition.
(I've seen this before)
(Other definitions for bark that I've seen before include "old vessel" , "Bay" , "Setter's sound" , "Woof" , "Shout gruffly; part of tree" .)