关键词: 混交林, 林木生长, 土壤理化性质, 杉木, 马尾松, 突脉青冈

Abstract: This study investigated the competitive growth dynamics between Pinus massoniana and Chinese fir (Cunninghamia lanceolata), and examined the influence of their respective mixed forest compositions on tree growth and soil physicochemical properties. The research focused on Chinese fir stands naturally invaded by P. massoniana through seed wind dispersal, as well as mixed forests P. massoniana and Chinese fir in combination with broadleaf species Cyclobalanopsis elevaticostata. Tree growth indices and soil physicochemical characteristics were measured and analyzed across these forest types. The main findings were as follows: (1) In the early stages, mixed broadleaf-conifer forests exhibited higher canopy closure and superior tree height, diameter at breast height (DBH), and volume growth compared to pure P. massoniana and Chinese fir mixed forests, despite a lower stand density due to higher mortality rates of broadleaf trees. Furthermore, P. massoniana demonstrated better growth than Chinese fir in both forest types. (2) Soil physical properties showed no significant variation across different soil layers within the same forest type. However, soil bulk density increased with depth, while capillary water-holding capacity and capillary porosity decreased in mixed broadleaf-conifer stands. (3) Soil pH was consistently below 4.5 and no difference in the same stand. The concentrations of total potassium, total phosphorus, organic matter, and alkali-hydrolyzable nitrogen were higher in mixed broadleaf-conifer forests compared to P. massoniana and Chinese fir mixed forests, although the levels of available potassium and phosphorus were lower. In conclusion, natural seed invasion of P. massoniana proved strong, with this species demonstrating greater suitability for growth in the region. Mixed broadleaf-conifer forests were more effective in enhancing soil fertility compared to pure P. massoniana and Chinese fir stands, with P. massoniana exhibiting superior growth in both forest types. These findings provided valuable insights for the sustainable management of artificial forests.

Key words: mixed plantation, tree growth, soil physicochemical properties, Cunninghamia lanceolata, Pinus massoniana, Cyclobalanopsis elevaticostata