Seedling recruitment of Austrocedrus chilensis in relation to cattle use, microsite environment and forest disease

Abstract

The forests of Austrocedrus chilensis in the Patagonian Andes suffer a disease known as “mal del ciprés”. The purpose of this work was to identify the relationship between A. chilensis seedling recruitment and disturbances (i.e., disease and cattle grazing), and to identify associations between seedling recruitment and microsite characteristics related to the disturbances. Eighteen sites with “mal del ciprés” were selected for study. In each site, symptomatic and asymptomatic plots were established and characterized. Five control sites, where the disease was totally absent, were also included. Cattle use and disease were negatively associated with A. chilensis natural regeneration. Both disturbances seemed to act synergically. In control sites the abundance of seedlings was never null and reached greater values with low cattle use. In symptomatic and asymptomatic plots of diseased forests, seedling abundance tended to be lower than in control forests and was generally null when cattle use was high. The disease was associated with microsite features such as low canopy cover, organic horizon thickness and high understory cover. Although these site conditions were negatively associated with seedling abundance, they could not completely explain the variation found in seedling recruitment.

Keywords

• forest decline
• “mal del ciprés”
• natural regeneration
• site effect