Allometric models for the estimation of foliage area and biomass from stem metrics in black locust

Abstract

Biogeosciences and Forestry Biogeosciences and Forestry Allometric models for the estimation of foliage area and biomass from stem metrics in black locust Stamatios R Tziaferidis (1) , Gavriil Spyroglou (2) , Mariangela N Fotelli (2) , Kalliopi Radoglou (3) Allometric equations relating trees' vascular system and other stem metrics with foliage area and mass are important to estimate their growth, carbon stocks and interactions with abiotic environment in terms of carbon and water balance. In this study we focused on Robinia pseudoacacia restoration plantations in Greece and aimed at establishing species-specific models to predict foliage leaf area and biomass based on stem traits. In particular, we evaluated stem cross-sectional areas of sapwood, current sapwood and total stem (sapwood and heartwood), measured at different tree heights, as predictors of leaf area and mass, based on the pipe model theory. Furthermore, we assessed the variation in the ratios of leaf area to different stem cross-sectional areas across the tree profile and we examined the relationships of diameter at breast height (DBH) with diameter at the base of the live crown and with leaf area. Taking into account the trees' DBH distribution according to the plantations' inventory, 25 black locust individuals were destructively sampled and the relationships among the studied traits were analyzed by means of multiple and simple linear regression at p<0.001. Foliage dry mass and area were best predicted by total stem cross-sectional area at mid-bole and stump height (R 2 =0.81), followed by current sapwood area at stump height (R 2 =0.74), which outperformed the most often used sapwood area (R 2 =0.70). DBH was also reliably estimating tree leaf area (R 2 =0.72) but was less precise, compared to total cross-sectional area, while it was a useful proxy of diameter at the base of the live crown (R 2 =0.80). In line with the pipe model theory, the ratio of leaf area to total cross-sectional area declined across the canopy basipetally, but only when total cross-sectional area was considered. Deviations from the sapwood-foliage functions described by the pipe model theory may be due to the small sample size and the variability in tree size in such developing restoration plantations. The produced species-specific relationships between stem and foliage metrics may be a useful tool to predict the carbon sequestration and climate change adaptation potential of black locust restoration plantations, which are often characterized by harsh site conditions.

Carbon sequestration and soil nitrogen enrichment in Robinia pseudoacacia L. post-mining restoration plantations

“…Apart from the annual litterfall, it is vital to identify the initiation and seasonal fluctuation of litterfall for a reliable estimation of its contribution to the carbon (and nitrogen) cycle and for providing input to vegetation models, which currently assume that litterfall flux is evenly distributed during the year (Zhang et al, 2014). We found that litterfall increased already during the growing season (May to August; Figure 3A), as similarly reported by Andivia et al (2018), and it partly coincided with the xerothermic period of the study site (Tziaferidis et al, 2022). Several studies have highlighted this sensitivity of litterfall dynamics to warmer and drier conditions (e.g., Aryal et al, 2015;Bou et al, 2015;Liu et al, 2015), which is probably aiming to limit the plants' drought stress (Reich, 1995).…”

“…The potential of black locust to store carbon in AGB increased steadily with age (Figure 4A). This is resulted by the increase in above-ground biomass with age, previously indicated by Tziaferidis et al (2022) for the same sites. A similar positive age effect is reported for R.pseudoacacia restoration plantations of the same age range (5-25 years; Zhang et al, 2010;Wang et al, 2015), as well as for younger plantations (Böhm et al, 2011).…”

Estimating Crown Biomass in a Multilayered Fir Forest Using Airborne LiDAR Data

“…The originally selected sample size was decreased from 25 to 13 according to the guidelines of the local forest service, due to the potential damage from the fallen trees and the sampling procedures to the understory. In fact, previous studies that focussed on allometric equations for biomass components estimation reported similar sample sizes to ours [10,73,[88][89][90]. Subsequently, a sample size of 13 was considered suitable for our study as well.…”

Effect of Geometry Precision and Load Distribution on Branch Mechanical Response

“…The nature of deflection curves combining both incline and curvature, as well as the sensitivity of curve shape to local changes of FEM properties were discussed in previous studies on stem response [13]. In future research, the use of the non-linear relationship between the diameter and the leaf area-or rather, cross-section area instead of diameter [43,55,56]-may be considered to obtain ratios that are closely related to frontal surface areas.…”