Valentín Pando

Key message: ATR-FTIR spectroscopy combined with statistical modelling provides accurate predictions of forest floor properties: total organic carbon, total nitrogen, total phosphorus and ash. Performance decreases in carbonate-rich samples, particularly for organic carbon and the carbon to nitrogen ratio; excluding such samples improves reliability. This makes ATR-FTIR a fast and sustainable complement to conventional chemical analyses for forest monitoring and nutrient cycling studies. Context: Organic forest layers and their decomposition are essential for nutrient cycling, soil fertility, and carbon sequestration in forest ecosystems. While infrared spectroscopy is widely applied to assess physical and chemical attributes in soil samples, its effectiveness in evaluating forest floor samples remains poorly studied. Aims: This study evaluated the efficacy of Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR) to predict forest floor properties: total organic carbon, total nitrogen, and their ratio, total phosphorus, and ash content. Methods: Forest floor material from a European network of forest plots was analyzed. Organic layers of Pinus sylvestris , L., Quercus spp., and Fagus sylvatica L. in monospecific and mixed forest stands were examined, differentiating between species and litter layers: undecomposed, intermediate decomposed, and humified. ATR-FTIR spectra (4000 to 400 cm ⁻¹ ) were recorded and analyzed. A modified partial least-squares method and a Generalized Linear Mixed Model with cross-validation were used to develop equations and predictive models for forest floor properties, combining ATR-FTIR spectra with laboratory data. Results: Accurate explanatory and predictive models were developed for forest floor samples using ATR-FTIR spectroscopy, highlighting its potential as a complementary or alternative tool to traditional chemical analyses. Total organic carbon predictions were more accurate when carbonate-containing samples were excluded from calibration. Conclusions: ATR-FTIR provides a reliable alternative for assessing forest floor properties, supporting sustainable forest management by improving monitoring of nutrient cycling and carbon storage.

Understanding the growth efficiency of individual trees, or growth per unit of resource utilization, can inform silvicultural management strategies to maximize tree and stand growth. Stand structure—the size and spatial distributions of trees within the stand—strongly influences water, light, and nutrient availability, as well as the resource-use efficiency of each tree. Key silvicultural tools for stand management include manipulating tree density, size distribution, and arrangement by controlling natural regeneration, artificial seeding, planting seedlings, and/or subsequent thinning of established trees. We analyzed two sets of plots from even-aged stands of common coniferous species in central Spain, 106 pure Scots pine (Pinus sylvestris) and 92 pure Mediterranean pine (Pinus pinaster), to examine the dynamics of the dominance hypothesis, the relationship between stand structure and growth, and the relationship between structure and growth efficiency. Our main findings revealed a negative impact of size-class uniformity on stand growth in both Scots pine and Mediterranean pine, while the positive effect of tree size on growth efficiency was supported for Mediterranean pine stands but uncertain for Scots pine. At the operational level, our results highlight how thinning intensity is more important than the thinning method in Mediterranean pinewoods and how thinning can benefit the provision of multiple ecosystem services. We also recommend integrating dominance effects on growth into individual tree modelling.

Bread and bakery products are among the most discarded food products in the world. This work aims to investigate the potential use of wasted bread to obtain a high-glucose slurry. Simultaneous hydrolysis of wasted bread using α-amylase and glucoamylase was carried out performing liquefaction and saccharification at the same time. This process was compared with a traditional sequential hydrolysis. Temperature and pH conditions were optimized using a response surface design determining viscosity, reducing sugars and glucose concentration during the enzymatic processes. The optimal conditions of pH and temperature in the saccharification stage and the simultaneous hydrolysis were pretty similar. Results show that the slurry produced with simultaneous process had a similar glucose yield at 2 h, and at 4 h a yield higher than that obtained by the sequential method of 4 h and could reduce time and energy.

The process of Land Consolidation (LC) is deemed an important instrument of rural development in many countries, where it contributes to the economic development and viability of their rural areas. This paper aims to analyze three areas of Castilla y León in Northwestern Spain, all having similar agronomic features. The above areas have recently undergone LC processes. This research proves LC can contribute to reducing greenhouse gases (GHG) using the rationalization introduced in the layout of the agrarian exploitations. For this purpose, this paper analyzes the effects of LC actions on the size, shape, and level of scattering of the owners affected and compares the energy consumption in every journey from the exploitation to each plot, as well as the number of row-end turnings within the plots. GHG reductions present significant differences depending on the LC technique carried out, the size of the area consolidated, and the different degrees of intensification of agricultural exploitations. Through the three LC projects analyzed, a reduction in GHG emissions of 23.60% in SA1, 11.46% in SA2, and 9.85% in SA3 would have been obtained. In total, 1067.34 t CO₂ of GHG emissions would have been mitigated. In the light of the results obtained, LC can be considered an efficient process in the strategy of GHG reduction, all in line with the current commitments derived from the Paris Agreement. It is also necessary to continue to research the structure and importance of the consumption of fossil fuels in farming and its possible link to emission reduction policies.

Aim of study: The native species of warm humid climates Ceiba pentandra, Tabebuia rosea, Gliricidia sepium, Enterolobium cyclocarpum and Brosimum alicastrum are often included in Mexican reforestation programs. We evaluated the growth response in sandy soils of these species that could serve as pioneers in the restoration of coastal areas. Area of study: Alluvial plain in Frontera, Tabasco, Mexico. Material and methods: A total of 1080 plants were planted in 2014 and evaluated for 23 months in 30 plots under a randomized block design with six replications. The sample plots each occupied 36 m² (each with 16 plants). Survival percentage, stem height (SH), basal diameter (BD) and basal area (BA) were quantified. Survival and growth variables were analyzed using logistic regression and ANOVA for repeated measures, respectively. Main results: At the end of the experiment (2016), high survival was demonstrated in G. sepium (88 %) and in C. pentandra (86 %), while B. alicastrum presented total mortality at six months. The highest values of SH and BD were presented in C. pentandra (2.9 m and 7.8 cm, respectively) and in G. sepium (2.6 m and 4.2 cm, respectively). Gliricidia sepium differed significantly from C. pentandra in terms of BA (5.9 vs. 23 m² ha^-1, respectively). Research highlights: The native species C. pentandra and G. sepium presented high survival and growth in the sandy soils; G. sepium showed strong adaptation to the environment and C. pentandra offered suitable coverage, characteristics that are necessary for the success of reforestation and restoration programs.