山西省吉县刺槐、油松人工林密度动态调控技术

摘要

运用基于耗水量的密度调控模型,结合降水量,估算了山西吉县刺槐(Robinia pseudoacacia Linn.)和油松(Pinus tabulaeformis Carr.)人工林不同林龄的合理林分密度.研究表明:①随着林龄的增加,各耗水量等级的林分密度均递减.但随着耗水量等级的增大,其林分合理密度水平也递增.②耗水量为450 mm时,以胸径连年生长量指标估算的刺槐(1 ～18a)、油松(5～40a)林合理密度分别为:562 ～3 666、1 969～2 642 株/hm2.以材积连年生长量指标估算的刺槐人工林合理密度为:733～3 752株/hm2.③耗水量为500 mm时,以胸径连年生长量指标估算的刺槐(1 ～18a)、油松(5～40 a)林合理密度分别为:1049～6 843、2 025 ～2 717株/hm2.以材积连年生长量指标估算的刺槐人工林合理密度为:871 ～4 456株/hm2.④在目前降水条件下,试验区人工林密度偏高,因此需要通过间伐处理降低密度.%A water consumption-based density control model, combined with precipitation conditions, was adopted to investigate the reasonable density for Robinia pseudoacacia and Pinus tabulaeformis plantations of different ages in Jixian County of Shanxi Province. Results showed that the stand density for different water consumption levels decreased with increasing stand age, but the reasonable density increased with increasing water consumption level. When the water consumption was 450 mm, the reasonable densities for R. pseudoacacia (1-18 a) and P. tabidaeformis plantations (5-40 a) were 562-3666 and 1 969-2 642 stems/hm2 respectively estimated in terms of annual increment in DBH. The reasonable density for R. pseudoacacia plantations was 733-3 752 stems/hm2 in terms of current annual increment in volume. When the water consumption was 500 mm, the reasonable densities for it pseudoacacia (1-18 a) and P. tabulaeformis plantations (5-40 a) were 1 049-6 843 and 2025-2 717 stems/hm2 respectively in terms of annual increment in DBH, while that for R. pseudoacacia was 871 -4 456 stems/hm2 in terms of current annual increment in volume. The plantation density in the experiment area is on the high side under the current precipitation condition, thus needs to be reduced by thinning treatment.