Considers vermin circling base of tree (5)
I believe the answer is:
rates
'considers' is the definition.
'vermin circling base of tree' is the wordplay.
'vermin' becomes 'rats' (I've seen this in another clue).
'circling' is an insertion indicator (circling can mean going around or containing).
'base of' says to take the final letters.
The last letter of 'tree' is 'e'.
'rats' going around 'e' is 'RATES'.
(Other definitions for rates that I've seen before include "Former means of local revenue" , "Property levy" , "Fees" , "Former local tax" , "classes" .)