Vegetation response to canopy gap creation and herbivore exclusion in exotic <i>Pinus radiata</i> plantation forest

Abstract Introduction Globally, there is potential to transition exotic Pinus plantation to native forest for ecosystem restoration, and retire plantations established in locations unsuitable for harvest. Creation of canopy gaps may promote transitions; however more research is required on optimal gap size and the influence of other interventions such as herbivore exclusion. Objectives To explore the influence of canopy gap creation and herbivore exclusion in Pinus plantation on regenerating communities of native and exotic vegetation. Methods We compared regeneration using a randomized block design with three replicates of strip harvesting treatments and an unharvested control in 14‐year‐old Pinus radiata plantations in Aotearoa New Zealand. Strips were 50 m long with widths of 9–27 m. Herbivores were excluded from half of each strip via deer fences. Results Primarily composed of herbaceous species, narrow strips produced the greatest species richness and total importance value (IV) of native regeneration. Though native tree and shrub IVs did not differ among treatments. Exotic grasses grew rapidly following canopy removal; however, their IV was significantly lower in narrow strips compared to the medium and wide. Herbivore exclusion increased exotic grass growth and had a negative effect on native regeneration in medium and wide strips. Changes in abiotic variables among strip treatments did not correlate with native regeneration. Available light had a strong positive effect on all exotic vegetation regeneration. Conclusions The narrow strip encouraged the most native regeneration while lower available light compared to medium and wide strips reduced competition with exotic grasses.