Effect of age and spacing on biomass production in forest plantations

ABSTRACT The aim of this study was to determine the effect of age and plant spacing on biomass production of four forestry tree species: Acacia mearnsii De Wild, Eucalyptus grandis W. Hill ex Maiden, Mimosa scabrella Benth, and Ateleia glazioviana Baill. The following spacings of plants at the ages of 1, 3, and 5 years after planting were considered: 2.0 × 1.0 m, 2.0 × 1.5 m, 3.0 × 1.0 m, and 3.0 × 1.5 m. The study was installed in randomized complete block design. Biomass was determined by weighing different components of the trees after harvesting. Plant spacing affected biomass production of forestry trees at different ages after planting. Dense spacings produced larger quantities of biomass than less dense spacing. The tree species differed in biomass production: Eucalyptus grandis produced the largest quantity (325.1 t ha-1), followed by Acacia mearnsii (239.3 t ha-1), Mimosa scabrella (53.4 t ha-1), and Ateleia glazioviana (32.1 t ha-1). Wood biomass represented the biomass component with the largest production over time, which showed an increasing proportion throughout the age groups, followed branch, leaf, and bark biomass.

摘要：本研究旨在探究树龄与种植株行距对4种林木生物量生产的影响，供试树种分别为黑荆（Acacia mearnsii De Wild）、巨桉（Eucalyptus grandis W. Hill ex Maiden）、糙荚含羞草（Mimosa scabrella Benth）以及格氏陀螺果（Ateleia glazioviana Baill.）。本研究设置了植后1年、3年、5年三个树龄阶段，以及2.0×1.0 m、2.0×1.5 m、3.0×1.0 m、3.0×1.5 m四种株行距处理。试验采用完全随机区组设计，通过采收后称量树木各组分的重量测定生物量。结果表明，株行距对不同植后树龄的林木生物量生产具有显著影响，高密度株行距处理的生物量产出高于低密度处理。供试4个树种的生物量产出存在显著差异：巨桉生物量最高，达325.1 t·ha⁻¹，其次为黑荆（239.3 t·ha⁻¹）、糙荚含羞草（53.4 t·ha⁻¹）以及格氏陀螺果（32.1 t·ha⁻¹）。木质部生物量是各组分中产出最高的组分，随树龄增长其占比持续提升，其后依次为枝条生物量、叶片生物量与树皮生物量。