Involved in defensive oleoresin formation in conifers in response to insect attack or other injury. Involved in diterpene (C20) olefins biosynthesis. Monofunctional enzyme lacking the DXDD motif in the class II active site relevant for the cyclization of geranylgeranyl diphosphate (GGPP). Requires (+)-copalyl diphosphate ((+)-CPP) as substrate, but no activity with GGPP or ent-CPP. Pimaradiene is the major products of the enzyme