Performance of planted native seedlings in felled strips within Pinus radiata plantation forest

Abstract Introduction Exotic plantations could facilitate native forest restoration through a managed transition utilizing partial harvest, poisoning, or natural senescence of the plantation. Objectives To explore canopy gap creation and herbivore exclusion in a Pinus radiata plantation on planted seedlings of three native tree species. Methods Growth and survival of planted seedlings were compared using a randomized split‐plot block design with three replicates of strip harvesting treatments and an unharvested control in a mid‐rotation (14‐year‐old) P. radiata plantation in Hawke's Bay, New Zealand. Felled strips were 50 m long with widths of 9–27 m. Unharvested controls were 50 m × 9 m, giving a total of nine strips and three controls. A deer fence around half of each strip excluded ungulates. Height, root collar diameter, and position of Podocarpus totara , Leptospermum scoparium , and Fuscospora solandri seedlings were measured at establishment and after 2.5 years. Survival and browse were monitored at 6‐monthly intervals. Results All species had significantly greater growth and survival in strip treatments compared to the control. However, no strip treatment produced greater seedling performance across all species. Leptospermum scoparium and F. solandri in the medium and wide strips with ungulate exclusion experienced reduced growth due to increased competition with exotic grasses without grazing pressure. However, seedlings of F. solandri and P. totara that were browsed also experienced increased mortality. Conclusions Gap creation improves growth and survival of planted native seedlings. Smaller gaps could be more effective where exotic grasses are common and grazing pressure is low.