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 本研究旨在探究林龄与种植株行距对4种林木生物量产出的影响，供试树种分别为黑荆（Acacia mearnsii De Wild）、巨桉（Eucalyptus grandis W. Hill ex Maiden）、布雷含羞草（Mimosa scabrella Benth）以及格氏蝶豆（Ateleia glazioviana Baill）。本研究设置了造林后1、3、5年林龄下的4种株行距处理：2.0×1.0 m、2.0×1.5 m、3.0×1.0 m及3.0×1.5 m。试验采用完全随机区组设计，通过采收后称量林木各组分生物量的方式测定生物量指标。结果表明，种植株行距对不同造林年限林木的生物量产出具有显著影响，高密度株行距处理的生物量产出高于低密度处理。供试树种间生物量产出存在显著差异：巨桉的生物量最高，达325.1 t·hm⁻²，依次为黑荆（239.3 t·hm⁻²）、布雷含羞草（53.4 t·hm⁻²）及格氏蝶豆（32.1 t·hm⁻²）。随林龄增长，木质部生物量为占比最高的组分，且其在各林龄组中的占比呈持续上升趋势，其次依次为枝条、叶片及树皮生物量。