The most common and most likely answer to this crossword clue is the 8 plus 6 letter word SHERWOOD FOREST
I've seen this crossword clue in The Daily Telegraph
S
H
E
R
W
O
O
D
F
O
R
E
S
T
More clues leading to the result SHERWOOD FOREST
Buddy explains!
The straight part
We know that "a place full of trees" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a place full of trees = sherwood forest.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.