A novel application of the ecological field theory to the definition of physiographic and climatic potential areas of forest species

A new approach to the definition of physio-graphic and climatic potential areas for forest species, based on the ecological field theory, is outlined in this paper. The proposed formulation is tested on the Spanish juniper (Juniperus thurifera L.), using data from 883 permanent and temporary plots throughout its distribution area in the Spanish autonomous region of Castilla y León. The suitability of the territory for the species is assessed by previously studying its habitat, which in turn is analyzed through physiographic and climatic parameters. This new method is rooted in an additive index that depends on the Mahalanobis distance in the parametric space that evaluates the ecological resemblance between the studied site and each of the points defining the parametric habitat. Thereby the ecological potential of any site within the territory can be established, integrated in a geographical information systems and accordingly charted. The results are compared with those obtained with the methodology traditionally used by Spanish foresters (factorial index), showing that the overall potential area is similar in size but quite different in its distribution. © Springer-Verlag 2008

Do thinnings influence biomass and soil carbon stocks in Mediterranean maritime pinewoods?

The effects of silvicultural treatments on carbon sequestration are poorly understood, particularly in areas like the Mediterranean where soil fertility is low and climatic conditions can be harsh. In order to improve our understanding of these effects, a long-term thinning experiment in a stand of Mediterranean maritime pine (Pinus pinaster Ait.) was studied to identify the effects of thinning on soil carbon (forest floor and mineral soil), above and belowground biomass and fine and coarse woody debris. The study site was a 59-year-old pinewood, where three thinnings of differing intensities were applied unthinned (control), moderate thinning and heavy thinning. The three thinning interventions (for the managed plots) involved whole-tree harvesting. The results revealed no differences between the different thinning treatments as regards the total soil carbon pool (forest floor + mineral soil). However, differences were detected in the case of living aboveground biomass and total dead wood debris between unthinned and thinned plots; the former containing larger amounts of carbon. The total carbon present in the unthinned plots was 317 Mg ha-1; in the moderately thinned plots, it was 256 Mg ha-1 and in the case of heavily thinned plots, 234 Mg ha-1. Quantification of these carbon compartments can be used as an indicator of total carbon stocks under different forest management regimes and thus identify the most appropriate to mitigate the effects of global change. Our results indicated that thinning do not alter the total soil carbon content at medium term, suggesting the sustainability of these silvicultural treatments. © 2012 Springer-Verlag Berlin Heidelberg

Development of tools to estimate the contribution of young sweet chestnut plantations to climate-change mitigation

10 Pág. Instituto de Ciencias Forestales (ICIFOR)Sweet chestnut plantations, irrespective of their main productive orientation (nut or timber production), are key elements of the landscape as well as the cultural heritage of the areas where they are found and provide important functions and services. Hence, recent initiatives have been aimed at extending the area occupied by chestnut trees through forest plantations. Nevertheless, the role of these young chestnut plantations as carbon sinks has been often ignored. The National Inventory of Greenhouse Gas Emissions (GHG) must include estimates of the so-called ‘transition forests’ during the 20 years following their plantation. In this study, new tools for estimating the total amount of above and belowground biomass stored in young plantations of chestnut were developed to quantify the carbon storage capacity of these plantations. A new set of aboveground biomass and root-shoot ratio models were fitted for individual-tree level based on four different independent variables – root collar diameter, total height, diameter at breast height and crown projection area – and their combinations. The expansion to stand level was based on age, plantation density, productive orientation of the plantation (nut or timber), site index and climate covariates as possible independent variables. At tree level, the best aboveground biomass models were those that include the product of root-collar or breast height diameters and tree height, whereas for root-shoot ratio the best results were obtained when only diameter at breast height is included. At stand level, the most accurate models included age, plantation density and site index for aboveground biomass and only age for root-shoot ratio. The fitted models provided accurate and unbiased predictions of aboveground biomass in the first years of reforestations. The different fitted equations can be used to estimate carbon stocks in young plantations depending on the available data and the objective of the prediction. Individual tree-level equations are recommended when accurate estimates are needed and detailed inventory measurements are available. Stand level equations, only using plantation age, can be an appropriate alternative for use with forest statistics at national scale, although the inclusion of additional covariates can greatly improve the accuracy of the age-based stand level equations. Our results indicated that even low-density nut-oriented chestnut plantations can play a relevant role as C sinks.The authors wish to thank CICYTEX (Elena Nieto and Paula Serrano) and CESEFOR Foundation (Roberto Rubio and Darío Arias) for their valuable help in identifying and locating chestnut plantations and contacting farm owners. This research was funded by the Ministry of Science, Innovation and Universities grant number AGL2017-83828-C2-1-R; Ministry of Agriculture, grant number EG17-042-C02-02; and INIA grant number IMP- 2018-004-C02-02. The publication is also part of the CARE4C Project, which has received funding from the European Union’s HORIZON 2020 Research and Innovation Program under the Marie Sklodowska-Curie grant agreement N° 778322. We thank Adam Collins for revising and editing the English grammar.Peer reviewe