Tesla leading foundation associated with trees needed for seasonal ritual (5-7)
I believe the answer is:
first-footing
'seasonal ritual' is the definition.
The definition suggests an adjective which matches the answer.
'tesla leading foundation associated with trees' is the wordplay.
'tesla' becomes 'T' (scientific unit).
'leading foundation' becomes 'footing' (footing is a kind of foundation. I am not sure about the 'leading' bit.).
'associated with' says to put letters next to each other.
'trees' becomes 'firs' (fir is a kind of tree).
't'+'footing'='tfooting'
'tfooting' after 'firs' is 'FIRST-FOOTING'.
'needed for' acts as a link.
Can you help me to learn more?
(Other definitions for first-footing that I've seen before include "Scottish custom" , "Seasonal activity" .)