Influence of elevation on the distribution characteristics and carbon storage of Chinese fir

To improve the management level of Chinese fir (Cunninghamia lanceolata), the impact of elevation on the spatial distribution and carbon storage of Chinese fir in Dehong Prefecture was analyzed by GIS technology and the forest volume conversion method. The results showed that the variations in soil type, slope gradient, and aspect induced by altitude differences exerted impacts on the distribution area and standing volume of Chinese fir, thereby leading to changes in volume per hectare and carbon storage. Chinese fir exhibit a spatial distribution pattern of "scarcity at both ends and abundance in the middle" along the altitude gradient, which was predominantly distributed between 701 m and 2500 m, covering an area of 78,064.14 hm² with a carbon storage of 4,039,932.83 t, accounting for 99.94% and 99.95% of the total, respectively. The species was most densely distributed on slopes of 16–25°, with a higher presence on shady slopes than on sunny slopes. The associated soils were mainly latosolic red soil and red soil, with latosolic red soil being the most prevalent. The volume per hectare, average canopy closure, carbon density, and carbon storage per unit area of Chinese fir decreased with increasing altitude. Chinese fir was suitable for growth between 701 m and 1800 m above sea level,and its carbon density was the highest. The largest distribution area and carbon storage occured between 1001 m and 1800 m, while only 0.06% of the total distribution was found in the low-altitude range (262–700 m) and high-altitude range (2501–2625 m). Within the same altitude segment, near-mature, mature, and over-mature Chinese fir stands exhibit higher carbon storage per unit area and stronger carbon sequestration capacity, followed by middle-aged stands, with young stands showing the lowest values. Accordingly, based on the altitude gradient, this paper proposed to enhance the management of Chinese fir from three aspects: rational optimization of spatial layout, implementation of forest management practices, and leadership via scientific and technological innovation, so as to improve forest quality, expand forest land space, develop inter-forest economies, increase farmers’ income, and achieve diversified, green, healthy, and sustainable development of forest lands.