Some articles on dendix:

Dry Ski Slope - Materials - Brush Materials
... The most common material is dendix, a by-product of brush manufacturing which is similar to a short-haired brush with the bristles sticking upwards ... Dendix is manufactured in Chepstow, however it can be found on slopes throughout the world ... water is often sprayed onto the surface of the dendix to lubricate it and increase speed however, higher insurance premiums cause many slope operators to look for safer ...