ABSTRACT

This study aims to derive individual tree allometric equations for the above- and belowground biomass components of grey and common alder based on data sets obtained in Latvia. The species aboveground biomass data consisted of 81 trees collected in 27 forest stands. The belowground biomass data were obtained from 27 common alder and 28 grey alder trees sampled throughout Latvia. For grey and common alder, the root-to-shoot ratio decreased with increasing tree dimensions. Our analysis revealed that biomass functions currently used in the national forest inventory overestimate grey alder and underestimate common alder biomass stocks in Latvia. Our findings indicate that the existing local aboveground biomass equation has an overall satisfactory predictive ability compared to the derived equations in this study. The equations from southern Sweden underestimate biomass for mature trees and overestimate small tree biomass, suggesting that even in the hemiboreal region, the grey and common alder populations could have a different distribution of biomass allocated to various components. Model examinations indicated that the derived allometric functions for grey and common alder were unbiased and performed well within the data range and are the best available to substantially improve national estimates of carbon sequestration and biomass resources in Latvia.

摘要

本研究旨在根据在拉脱维亚获得的数据集推导出灰桤和普通桤木地上和地下生物量组分的个别树木异速生长方程。地上生物量数据包括在 27 个林分中收集的 81 棵树木。地下生物量数据是从整个拉脱维亚采样的 27 棵普通桤木和 28 棵灰桤树中获得的。对于灰桤木和普通桤木，根茎比随着树木尺寸的增加而降低。我们的分析表明，目前在国家森林清单中使用的生物量函数高估了拉脱维亚的灰桤木并低估了普通桤木生物量库。我们的研究结果表明，与本研究中的导出方程相比，现有的局部地上生物量方程具有总体令人满意的预测能力。瑞典南部的方程低估了成熟树木的生物量而高估了小乔木的生物量，这表明即使在北半球地区，灰桤木种群和普通桤木种群的生物量分布也可能不同。模型检查表明，灰桤和普通桤木的异速生长函数是无偏的，在数据​​范围内表现良好，是显着改善拉脱维亚国家碳固存和生物质资源估算的最佳方法。