Act the wrong way, cutting precious tree (6)

'tree' is the definition.
(deodar is a kind of tree)

'act the wrong way cutting precious' is the wordplay.
'act' becomes 'do' (to do is to act or execute a task).
'the wrong way' says the letters should be written in reverse.
'cutting' is an insertion indicator (some letters cut their way into a word).
'precious' becomes 'dear' (I've seen this before).
'do' written backwards gives 'od'.
'od' inserted inside 'dear' is 'DEODAR'.