Silvery grey tree (3)
I believe the answer is:
ash
I believe this is a double definition.
'silvery grey' is the first definition.
(I've seen this before)
'tree' is the second definition.
(ash tree is a kind of tree)
(Other definitions for ash that I've seen before include "Rowan tree is also called the mountain . . ." , "Tree with winged seeds" , "blonde" , "Tree - effect of burning" , "Remains of conflagration" .)