Adaptation of the Coniferous Forests to Natural Fire Disturbances in the Altai Mountains, Xinjiang, China

Abstract

The Altai Mountains, located in the northwesternmost part of China, have a harsh climate and little human activity, making it an excellent location to study forest ecology undisturbed by human interference. The forest is frequently struck by lightning and experiences long-term natural fire disturbances, leading to the evolution of unique fire adaptation traits in the major conifer species. To explore the role of natural fire disturbances in the Altai Mountain forest ecosystem, we conducted a study on the fire adaptation traits of Larix sibirica, Pinus sibirica, Picea obovata, and Abies sibirica, and reconstructed the fire history of the forest area over the past 100 years. We investigated three representative forest areas with varying fire disturbance conditions and habitats in the Altai Mountains. Data on fire disturbance conditions, relative air humidity, and species composition were collected in these areas. Basal diameter to diameter at breast height, relative bark thickness, and under-crown heights were measured and counted for each of the four species, and litter, bark, and wood layers were sampled and analyzed for physicochemical properties (ash, fat, and higher heating value) for each of the four species in the plots examined. We conducted a count of the four conifer species in the forest for each fire adaptation index and analyzed the differences in fire adaptation traits among the species. Larix sibirica showed fire-tolerant traits, Pinus sibirica displayed fire-embracer traits, and Picea obovata and Abies sibirica exhibited fire-avoider traits. Through the analysis of stand composition and exposure to fire disturbance in the different forest areas, we were able to correlate the fire-adaptive strategies of the four conifers with stand characteristics under varying fire disturbances and habitats. The interaction between forests and fires, and their adaptation to each other, ultimately create the current ecosystems in the Altai Mountains.