ABSTRACT

The present study was conducted to estimate relative growth rates (RGR) and above- and below-ground biomass stocks of 10 tree species commonly planted in arid irrigated urban areas in Pakistan. Saplings were grown in the Botanic Garden of Government College University, Lahore. The growth was monitored for a year and a half and then trees were destructively harvested to assess biomass stocks. The mean relative growth rate ranged from 0.03 ± 0.021 cm cm⁻¹ day⁻¹ to 0.28 ± 0.016 cm cm⁻¹ day⁻¹. The mean above-ground oven dried biomass ranged from 0.51 ± 0.071 kg to 28.34 ± 3.746 kg, while the mean below-ground biomass ranged from 0.12 ± 0.053 kg to 7.35 ± 0.605 kg. Further, we found that the RGR was significantly and positively correlated with above-ground biomass, below-ground biomass, and root-shoot ratios. Across all 80 individuals of the studied species, diameter at tree base was significantly and positively related to whole tree biomass (R² = 0.80). In this study we have developed the species-specific equations to estimate biomass in young urban species. Such data will be helpful for plantation decision makers, who may need to select the species according to relative growth rates and biomass allocation.

摘要

本研究旨在估计巴基斯坦干旱灌溉城市地区常见的 10 种树种的相对增长率 (RGR) 和地上和地下生物量储量。树苗生长在拉合尔政府学院大学的植物园。对生长进行了一年半的监测，然后破坏性地砍伐树木以评估生物量存量。平均相对增长率范围为 0.03 ± 0.021 cm cm ⁻¹ day ⁻¹至 0.28 ± 0.016 cm cm ⁻¹ day ⁻¹. 平均地上烘干生物量范围为 0.51 ± 0.071 千克至 28.34 ± 3.746 千克，而平均地下生物量范围为 0.12 ± 0.053 千克至 7.35 ± 0.605 千克。此外，我们发现 RGR 与地上生物量、地下生物量和根冠比显着正相关。在所研究物种的所有 80 个个体中，树基直径与整棵树生物量显着正相关 (R ²  = 0.80)。在这项研究中，我们开发了特定于物种的方程式来估计年轻城市物种的生物量。这些数据将有助于种植园决策者，他们可能需要根据相对增长率和生物量分配来选择物种。