In Mediterranean ecosystems an increasing demand for in situ trace gas exchange data is emerging to enhance the adaptation and mitigation strategies under forest degradation. Field-chamber green-house gas fluxes and site characteristics were analysed in two Mediterranean peri-urban pine forests showing degradation symptoms. We examined the effect of different thinning interventions on soil CO<inf>2</inf>, CH<inf>4</inf> and N<inf>2</inf>O fluxes, addressing the relationships with the environmental variables and C and N contents along forest floor-soil layers. Soil temperature resulted as the main driving variable for CO<inf>2</inf> efflux and CH<inf>4</inf> uptake. Soil moisture content and organic matter availability affected CO<inf>2</inf> emission patterns in the two sites. N<inf>2</inf>O fluxes showed a positive correlation with soil moisture under wetter climatic conditions only. GHG fluxes showed significant correlations with C and N content of both forest floor and mineral soil, especially in the deepest layers, suggesting that it should be considered, together with environmental variables when accounting GHG fluxes in degraded forests. Short-term effects of thinning on CO<inf>2</inf> emissions were dependent on disturbance induced by logging operations and organic matter inputs. After thinning CH<inf>4</inf> uptake increased significantly under selective treatment, independently from specific site-induced effects. N<inf>2</inf>O fluxes were characterized by low emissions in both sites and were not affected by treatments. Soil CO<inf>2</inf> efflux was the largest component of global warming potential (GWP) from both sites (11,553 kg ha⁻¹ y⁻¹ on average). Although it has a large global warming potential, N<inf>2</inf>O contribution to GWP was about 131 kg CO<inf>2</inf>eq ha⁻¹ y⁻¹. The contribution of CH<inf>4</inf>-CO<inf>2</inf> equivalent to total GWP showed a clear and significant CH<inf>4</inf> sink behaviour under selective treatment (36 kg ha⁻¹ y⁻¹ on average). However, in the short-term both thinning approaches produced a weak effect on total GWP. © 2018 Elsevier B.V.

Water availability is a major limiting factor in plant productivity and plays a key role in plant species distribution over a given area. New technologies, such as terahertz quantum cascade lasers (THz‐QCLs) have proven to be non‐invasive, effective, and accurate tools for measuring and monitoring leaf water content. This study explores the feasibility of using an advanced THz-QCL device for measuring the absolute leaf water content in Corylus avellana L., Laurus nobilis L., Ostrya carpinifolia Scop., Quercus ilex L., Quercus suber L., and Vitis vinifera L. (cv. Sangiovese). A recently proposed, simple spectroscopic technique was used, consisting in determining the transmission of the THz light beam through the leaf combined with a photographic measurement of the leaf area. A significant correlation was found between the product of the leaf optical depth (τ) and the leaf surface area (LA) with the leaf water mass (Mw) for all the studied species (Pearson’s r test, p ≤ 0.05). In all cases, the best fit regression line, in the graphs of τLA as a function of Mw, displayed R2 values always greater than 0.85. The method proposed can be combined with water stress indices of plants in order to gain a better understanding of the leaf water management processes or to indirectly monitor the kinetics of leaf invasion by pathogenic bacteria, possibly leading to the development of specific models to study and fight them. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.