Size structure, growth and regeneration of tropical conifers along a soil gradient related to altitude and geological substrates on Mount Kinabalu, Borneo

作者：Sawada Yoshimi^*; Aiba Shin ichiro; Seino Tatsuyuki; Kitayama Kanehiro

来源：Plant and Soil, 2016, 403(1-2): 103-114.

DOI：10.1007/s11104-015-2722-z

• Conifer-angiosperm coexistence
• Light condition
• Sapling
• Seedling
• Soil nutrients

Conifers often co-occur with angiosperm trees at high altitudes and on infertile soils in tropical rainforests. To explore the mechanism of conifer-angiosperm coexistence, we investigated size structure, growth rate and regeneration of conifers along soil gradient across altitudes and geological substrates.
Tree measurements were conducted in ten plots (0.06-1 ha) with varied geology at four altitudes (700, 1700, 2700 and 3100 m) on Mount Kinabalu, Borneo. Conifer juveniles were counted and understory light conditions were analyzed with hemispherical photographs.
Size structure of conifers showed inverse-J shape distributions on ultrabasic rocks at a parts per thousand yen1700 m but unimodal or sporadic distributions in other plots. Densities of conifer seedlings and saplings were generally greater on ultrabasic rocks than on non-ultrabasic substrates at comparable altitudes, which concurred with the pattern in understory light conditions. Growth rates over 4 (or 5) years of conifers at 4.8-25 cm diameter were higher than angiosperm trees only under well-lit conditions on non-ultrabasic substrates, but were always similar or higher on ultrabasic rocks even in shaded conditions.
Conifers showed continuous regeneration on ultrabasic rocks at a parts per thousand yen1700 m. This suggested that, on infertile soils, competition with angiosperm trees was relaxed and well-lit understory facilitated recruitment of conifers.

• 出版日期2016-6