The most common and most likely answer to this crossword clue is the 8 letter word MANGROVE
I've seen this crossword clue in The Times
M
A
N
G
R
O
V
E
More clues leading to the result MANGROVE
- Fellow with dog taken short hangs around good shrub
- Morgan pranged against English tree
- Short scruffy wanderer, taken short, finds a tree
- Bloke and dog finally wander in vegetation
- Servant and head gardener upset over tropical tree
- Tree supplying person with wood
- Chap goes to small wood to get tree
- Having come a cropper, move gran’s greenery
- Right checking fruit — and very English! — that grows in swamps
- Take action when silly gran gets stuck in shrub
Buddy explains!

The straight part
We know that "tree" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case tree = mangrove.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 MANGROVE mean?
MANGROVE noun- Any of various tropical evergreen trees or shrubs that grow in shallow coastal water.
- A habitat with such plants; mangrove forest; mangrove swamp.
- Plants of the Rhizophoraceae family.
- Trees of the genus Rhizophora.