Carbon content of forest floor and mineral soil in Mediterranean Pinus spp. and Oak stands in acid soils in Northern Spain

Abstract

Aim of study: The aim of the study was to determine the baseline carbon stock in forest floor and mineral soils in pine and oak stands in acid soils in Northern Spain.Area of study: The study area is situated in northern Spain (42° N, 4° W) on "Paramos y Valles" region of Palencia. Material and methods:An extensive monitoring composed of 48 plots (31 in pine and 17 in oak stands) was carried out. Litter layers and mineral soil samples, at depths of 0-30 cm and 30-60 cm, were taken in each plot. An intensive monitoring was also performed by sampling 12 of these 48 plots selected taken in account species forest composition and their stand development stage. Microbial biomass C (C MB ), C mineralization (C RB ), and soil organic C balance at stand level were determined in surface soil samples of intensive monitoring.Main results: No differences in soil C content were detected in the two forest ecosystems up to 60 cm depth (53.0±25.8 Mg C ha -1 in Pinus spp. plantations and 60.3±43.8 Mg C ha -1 in oak stands). However, differences in total C (C T ), C MB and C RB were found in the upper 10 cm of the soils depending on the stand development stage in each species forest composition (Pinus nigra, Pinus pinaster, Pinus sylvestris and Quercus pyrenaica). Plots with high development stage exhibited significant lower metabolic quotient (qCO 2 ), so, meant more efficient utilization of C by the microbial community. The C content in the forest floor was higher in pine stands (13.7±0.9 Mg C ha -1 ) than in oak stands (5.4±0.7 Mg C ha -1 ). A greater turnover time was found in pine ecosystems vs. oak stands. In contrast, forest floor H layer was nonexistent in oak stands.Research highlights: Results about litterfall, forest floor and mineral soil dynamics in this paper can be used strategically to reach environmental goals in new afforestation programs and sustainable forest management approaches.

Impact of tree species replacement on carbon stocks in a Mediterranean mountain area, NE Portugal

“…Also, according to Lal (2005) soils under natural forest, in general, have more soil organic carbon contents than those under managed forest plantations. Herrero et al (2016), in a study carried out in northern Spain, observed similar carbon content in soils when comparing plantations of Pinus spp. with natural Quercus pyrenaica areas (53 Mg C ha −1 vs. 60 Mg C ha −1 ), these values being, however, clearly lower than those found in the present study.…”

“…At all depths, soil carbon accumulation under PM and PN species is significantly lower than that under QP species, which can be justified by several effects as site preparation (Fonseca et al, 2014;Ferré et al, 2014), management practices (Zhang et al, 2016) and the nature of the litterfall produced by each tree species (Vesterdal et al, 2013;Cools et al, 2014;Zhang et al, 2016;Fonseca and Figueiredo, 2018). These factors may promote the breakdown of soil aggregates, affect soil biological activity and, consequently, the mineralization rate of organic residues in the forest floor and of soil organic matter (Gonçalves et al, 2013;Herrero et al, 2016;Fonseca and Figueiredo, 2018). In general, carbon storage displays a vertical gradient, tending to decrease with increasing mineral soil depth.…”

“…Although this substitution may have beneficial economic consequences, it is essential to understand environmental effects such as those in carbon sequestration for mitigation of greenhouse gases. The knowledge of the differences among species in what regards carbon sequestration and effects produced in each carbon pool of the ecosystem, should be a decision support tool when introducing new forest species and can be used strategically to reach environmental goals (Oostra et al, 2006;Schulp et al, 2008;Vallet et al, 2009;Herrero et al, 2016;Chen et al, 2016). Species replacement implies changes in carbon stocks in forest biomass and soils (Peltoniemi et al, 2004;Park, 2015), because tree species and litter quantity, quality and distribution in soil horizons have high influence in carbon storage (Lal, 2005;Oostra et al, 2006;Fonseca and Figueiredo, 2018).…”

“…Within the Kyoto Protocol and with the aim of generating carbon credits, some countries have been increasing the areas occupied by forests, improving management practices in existing areas or reorienting their production, an alternative for valuing of forests in relation to traditional logging (Cairns and Lasserre, 2004). Adequate species selection is a management option to increase carbon storage in forest systems (Vallet et al, 2009;Chen et al, 2016;Herrero et al, 2016).…”

Stand and environmental data from Pinus halepensis Mill. and Pinus sylvestris L. plantations in Spain

“…The Sustainable Forest Management Research Institute (iuFOR; University of Valladolid and INIA) also has a network of permanent plots in Pinus sylvestris plantations which consisted of rectangular 30 × 20-m plots. These plots have previously been studied to quantify the C sequestration in soils and forest biomass in Pinus sylvestris stands (Herrero and Bravo 2012;Herrero et al 2016;Herrero de Aza et al 2011).…”