Coppice material may be pinker after being pollarded (5)
I believe the answer is:
osier
'coppice material' is the definition.
(a coppice may be made up of osier trees)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for osier that I've seen before include "Withy" , "Willow with twigs for basket-weaving" , "Twig used in basket-making" , "Willow used in weaving" , "Willow for basket-making" .)