Simplicity is key: restoration protocols for nonregenerating forests degraded by overabundant herbivores

Abstract

AbstractGlobal forests are being lost and degraded at an alarming rate; hence ecological restoration becomes an integral component ensuring future forest health. Beneficial effects of restoration will depend on scientifically based practices within an adaptive management framework. On the island of Newfoundland, moose (Alces alces) have become overabundant since their introduction in the early 1900s causing regeneration failure of the balsam fir (Abies balsamea) forest. Intensive selective browsing by moose on this foundation species within naturally insect‐generated gaps has created “spruce‐moose meadows.” Experimental restoration to support Parks Canada Ecological Integrity targets was implemented in the boreal forest of Terra Nova National Park (Newfoundland, Canada), along a gradient of disturbance from closed canopy forest to large insect‐disturbed gaps. Seedling planting was carried out under various ground preparation treatments (field planting, aboveground suppression, and scarification). Seedling performance (survival, growth, and browsing occurrence) was monitored over 2 years and mixed‐effects models were constructed to determine seedling responses, which form the template of future forests. Results show minimally positive effects of the ground treatments along the gradient of disturbance, while environmental conditions and seedling individual traits explained the majority of seedling responses. Better growth, lower survival, and higher browsing intensity were observed with increasing forest disturbance, with taller seedlings at planting performing the best. Considering that no substantial biological benefits were detected following ground treatments, which are costly and time‐consuming to implement, active restoration in boreal forest can be implemented using standard forestry planting protocols, without any ground preparation, independently of the forest degradation state.