The most common and most likely answer to this crossword clue is the 9 letter word DECIDUOUS
I've seen this crossword clue in The Daily Telegraph
D
E
C
I
D
U
O
U
S
Buddy explains!
The straight part
We know that "Such trees are barely recognisable in winter" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case such trees are barely recognisable in winter = deciduous.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does DECIDUOUS mean?
DECIDUOUS adjective- Describing a part that falls off, or is shed, at a particular time or stage of development.
- Of or pertaining to trees which lose their leaves in winter or the dry season.
- Transitory, ephemeral, not lasting.