The use of shelters improves growth and survival of the endangered Nothofagus alessandrii after 5 years in a Mediterranean drought-prone site

Abstract

The ruil (Nothofagus alessandrii Espinosa) forest is one of the most endangered-endemic forest ecosystem in central Chile. The species is classified as shade- intolerant, but at the early stages of development the species behave as shade- tolerant, and its transition from shade to sun is unknown. In this study we presented the following scientific question: Does protection from direct sun exposure, beyond the initial establishment phase, improve the outplanting performance of N. alessandrii? By establishing planting stock of two qualities under two light levels (full sun versus black mesh shelters) and three irrigation frequencies in a Mediterranean drought-prone site, we assessed the performance of N. alessandrii trees (i.e., survival, root collar diameter, height, and individual tree volume) for 5 years after outplanting. The effect of planting stock and irrigation frequency were not significant. Our results of irrigation suggest that large amounts of water at low frequencies are inefficient in drought-prone sites. Those plants growing under shelters had a height and survival 32 and 55% higher with respect to full sun trees. The effect of the light level on height and survival varied by age. In the shelter treatment, survival was drastically reduced when plants overpassed the shelter height of 1 m. At age 5 years, survival in sheltered and no sheltered trees was reduced by 54 and 80%, respectively, relative to the survival values of the first year after outplanting. We concluded that initial establishment of N. alessandrii must consider the use of shelters beyond the early stages of development.