Early seedling establishment of endangered and valuable tree species in cloud forest restoration plantings

Abstract

Tropical montane cloud forests (TMCF) host high biodiversity and endemicity and are severely threatened by illegal selective logging, deforestation, fragmentation and climate change. The fragments of TMCF present high heterogeneity over short spatial intervals and a regional forest restoration approach must therefore incorporate seedling performance throughout the TMCF elevation range. We examined early seedling establishment in 12 endangered and valuable TMCF species in the understory of unplanned selectively logged TMCF and assessed the influence of elevation and canopy cover on seedling performance. Tree seedlings (10-18 mo-old) were transplanted into restoration plantings in 6 forest sites along an elevation range (1,250 to 1,995 m) in Veracruz, Mexico. In each forest, 30 seedlings per species were planted and their survival and relative growth rates in height (RGRh) and basal stem diameter (RGRd) recorded, along with canopy cover. Survival was high for all species after one year (81.1 to 99.4%) and was unaffected by elevation. Canopy cover positively affected the survival probability of 3 species. Both RGRh and RGRd decreased at lower elevations in 4 species; however, overall growth rates were positive. Our results indicate a positive early seedling establishment response in the evaluated tree species under the TMCF canopy (66-97% of canopy cover).