Shrub biomass accumulation and growth rate models to quantify carbon stocks and fluxes for the Mediterranean region

Abstract

The importance of shrub formations in the Mediterranean area both in terms of area occupied and carbon sequestered by them is currently being recognized. However, due to the lack of suitable models to estimate biomass accumulation and growth rate in this region, the carbon sequestered by these formations is not included when computing the total carbon stocks in aboveground biomass in Mediterranean forest ecosystems, according to the IPCC guidelines. The aim of the present study is to develop equations to predict biomass accumulation and growth rate for the main shrub formations in the region of Andalusia (Southern Spain), using the fraction of canopy cover (FCC m ) and the average height of the shrub formations (H m ) as predictors. To build these models, more than 800 plots were inventoried using destructive sampling; the mean value found in the region for biomass accumulation and annual growth rate being 16.73 Mg ha -1 and 1.14 Mg ha -1 year -1 , respectively. Heathers and big-size Cistaceae formations were the ones that presented the highest values of biomass accumulation (24.99 and 21.01 Mg ha -1 , respectively), while the highest values for annual growth rate were achieved by Leguminous gorse shrubs and, again, bigsize Cistaceae bushes (1.49 and 1.64 Mg ha -1 year -1 , respectively). The carbon content for the main shrub species and formations in the area was also obtained. The developed models provide the opportunity to estimate shrub carbon stocks in Mediterranean forest management from easy-toobtain variables, namely FCC m and H m . Moreover, the used shrub formations classifications and model structure allow their applicability to compute biomass accumulation and growth rate at regional and national level using as input data from the Spanish National Forest Inventory.

Forest management and carbon sequestration in the Mediterranean region: A review

“…An increasing amount of research in recent years has been focused on estimating the carbon stocks in Mediterranean shrublands, mainly through the development of estimation tools (e.g., Navarro & Blanco, 2006;Corona et al, 2012;Ruiz-Peinado et al, 2013b;Botequim et al, 2014;Pasalodos-Tato et al, 2015). The importance of shrub layer will depend on the ecosystem considered, the shrub species and tree density among other factors.…”

“…National carbon estimations for Spanish shrublands have been conducted by Montero et al (2016) using models for different shrub associations (Pasalodos-Tato et al, 2015). The results suggest that aboveground shrub biomass accounts for more than 91 Tg C. This figure represents 8.2% of the tree carbon stock in Spanish forests (Montero & Serrada, 2013), highlighting the importance of including shrubland in carbon accounts.…”

Estimation of Total Biomass in Aleppo Pine Forest Stands Applying Parametric and Nonparametric Methods to Low-Density Airborne Laser Scanning Data

“…The inclusion of understory vegetation in carbon sequestration has been traditionally ignored [12] since it represents lower amounts of biomass compared with tree aboveground biomass (AGB). However, considering the global scale this amount constitutes an important pool for carbon sequestration [12,13].…”

Carbon concentrations of components of trees in 10-year-old Populus davidiana stands within the Desertification Combating Program of Northern China

“…In India, Singh and Lodhiyal (2009) also estimated the tree biomass and C allocation in an 8-year-old poplar plantation based on the same value of 47.5%. Subsequent analyses showed that C concentration can vary between different components within the same tree species, resulting in C ratios ranging from above to below 50% (Zheng et al, 2008;Tolunay, 2009;He et al, 2013;Pasalodos-Tato et al, 2015). The accuracy of C content assessments has been improved with estimations of C concentration in each tree component (Li et al, 2011).…”