So inspect fallen tree (5,4)
I believe the answer is:
scots pine
'tree' is the definition.
(Scots pine is an example)
'so inspect fallen' is the wordplay.
'fallen' is an anagram indicator.
'so'+'inspect'='soinspect'
'soinspect' with letters rearranged gives 'SCOTS PINE'.
(Other definitions for scots pine that I've seen before include "Tree common in the Highlands" , "Conifer native to Britain" , "Coniferous tree" , "Kind of 3" , "One may provide deal" .)