It helps climbers in large area with dry rocks (7)
I believe the answer is:
lattice
'it helps climbers' is the definition.
(support for climbing plants)
'large area with dry rocks' is the wordplay.
'large' becomes 'L' (eg in clothes sizes).
'area' becomes 'a' (maths abbreviation).
'with' is a charade indicator (letters next to each other).
'dry' becomes 'tt' (short for teetotal - no alcohol).
'rocks' becomes 'ice' (both can informally mean diamonds).
'l'+'a'+'tt'+'ice'='LATTICE'
'in' is the link.
(Other definitions for lattice that I've seen before include "Network of crossed bars" , "Fretwork, grille" , "Network of crossed laths" , "Regular atomic structure" , "Trellis: maybe" .)