Burden I'd taken up about my work in preservation (9)
I believe the answer is:
taxidermy
'work in preservation' is the definition.
'burden i'd taken up about my' is the wordplay.
'burden' becomes 'tax' (I've seen this before).
'taken up' says the letters should be written backwards.
'about' becomes 're' (regarding**).
're' back-to-front is 'er'.
'tax'+'id'+'er'+'my'='TAXIDERMY'
(Other definitions for taxidermy that I've seen before include "The art of stuffing and mounting animal skins" , "Art of stuffing animals" , "A way to preserve wildlife?" , "Stuffing practice" , "preservation process" .)