Relative Growth Rate and Biomass Allocation Among Some Important Commonly Planted Trees in an Irrigated Urban Landscape

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.

KEYWORDS:

• Above- and below-ground biomass
• allometric equations
• functional traits
• growth rate
• urban forests