Deysi Alina Colachagua-Calderon

Agroindustrial lignocellulosic residues represent potential secondary resources, but their response to a common fractionation process can vary substantially with feedstock composition. This study evaluated organosolv processing of coconut fiber, maize cob, coffee parchment, and cocoa parchment under identical ethanol–acetic acid conditions. Untreated and processed solids were compared for physicochemical and compositional properties, and residue-specific responses were integrated using fiber enrichment, organic-solids equivalents, and non-dominance screening. Organosolv processing increased mean crude-fiber content from 25.04% to 66.74% and pH from 5.70 to 6.35; both effects remained significant after Holm correction. COD decreased in all residues, although the treatment-level response was not significant after multiplicity adjustment. Fiber enrichment occurred in every feedstock but varied markedly, with coffee parchment showing the largest proportional increase. Material-use profiles also differed: coconut fiber reached the highest crude-fiber concentration, whereas coffee parchment combined high fiber enrichment with the highest organic-solids equivalent and lowest ash content. Coconut fiber, maize cob, and coffee parchment were non-dominated under the exploratory screening. These results show that organosolv processing can produce fiber-enriched solids from contrasting agroindustrial residues, while the broader compositional outcome remains feedstock-dependent.

Agroindustrial residues represent heterogeneous biomass resources whose anaerobic conversion can be strongly influenced by pretreatment. This study evaluated seven residues: banana peel, potato peel, pineapple peel, coconut fiber, maize cob, coffee parchment, and cocoa parchment, under untreated, organosolv-treated, and precomposted conditions. Physicochemical and bromatological properties were characterized across the three biomass conditions, whereas baseline lignocellulosic composition was determined only for untreated materials. Methane production and biogas composition were assessed for the organosolv-treated and precomposted residues. Organosolv and precomposting produced contrasting compositional responses. Precomposted materials showed lower chemical oxygen demand and volatile-solid proportions, whereas organosolv largely preserved the organic fraction and increased the relative contribution of fiber and carbohydrates. Biochemical methane potential (BMP) differed markedly between pretreatments (p < 0.001), with organosolv-treated residues showing an average BMP 62.2% higher than that of precomposted residues. Methane concentration remained close to 50% and did not differ significantly between pretreatments. The first two principal components explained 79.2% of the compositional variation and showed distinct multivariate patterns among biomass conditions. Exploratory calculations based on experimental BMP and solids data estimated methane recoveries of 305.25 and 155.74 Nm³ CH₄ t⁻¹ wet biomass for organosolv-treated and precomposted materials, respectively. Under the conditions evaluated, organosolv showed greater potential for methane-oriented valorization and provides a basis for subsequent semi-continuous and pilot-scale evaluation.

Nursery decisions influence the condition of seedlings before outplanting, but their practical value depends on whether those traits remain evident during early field establishment. We evaluated Pinus douglasiana Martínez seedlings grown under eight combinations of container volume, fertilization, and irrigation regime. Seedlings were conditioned for six months in the nursery and then assessed after 12 months under field conditions. Container volume was the clearest source of variation. Compared with 1 L containers, 5 L containers produced seedlings with larger root collar diameter, greater shoot, root, and total biomass, and higher Dickson quality index. Total biomass was 2.2-fold greater in 5 L stock. Final survival was retained as a descriptive field variable and averaged 76.7% in 5 L treatments and 27.5% in 1 L treatments. Correlations based on treatment means associated total biomass with field diameter and descriptive survival, although these patterns were exploratory because only eight treatment means were available. Proline increased mainly under non-continuous irrigation, indicating a water-related nursery response, but it was not aligned with biomass production or first-year field performance. The treatment-level PCA separated biomass and field-growth variables from proline and lignification. These results show that larger containers improved the structural condition of P. douglasiana planting stock, although nursery costs, planting-site constraints, and longer monitoring should be considered before operational adoption.

Tropical mining landscapes require plot-based structural and carbon baselines to support restoration planning and environmental monitoring. This study estimated aboveground, root, and total tree carbon stocks across six mining concessions located in the Inambari River basin, Madre de Dios, southeastern Peruvian Amazon. Field inventories were conducted in 39 plots of 0.1 ha, where all trees with DBH ≥ 10 cm were measured. Aboveground biomass was estimated using a pantropical allometric equation based on wood density, diameter, and height; root biomass was estimated using a baseline root-to-shoot ratio of 0.24; and biomass was converted to carbon using a baseline carbon fraction of 0.47. Structural attributes, biomass stocks, carbon stocks, diameter-size profiles, basal-area contribution by diameter class, and multivariate structural-carbon patterns were evaluated among concessions. The concessions differed significantly in measured structural attributes, and these differences translated into contrasting derived biomass and tree carbon estimates. Edmilot I showed the highest basal area per hectare, total biomass, and total tree carbon, reaching 118.34 Mg C ha⁻¹, while Yesica recorded the lowest total tree carbon, with 58.54 Mg C ha⁻¹. Most trees were concentrated in the 10–20 cm and 20–30 cm DBH classes, but intermediate and larger trees contributed disproportionately to basal area. Principal component analysis summarized the concessions according to a reduced set of non-redundant structural and carbon variables, with the first two components explaining 99.21% of the total variation. These findings show that mining concessions retain contrasting forest conditions and should not be treated as homogeneous units. Structural and carbon baselines can help identify internal differences among concessions, prioritize restoration actions, and improve environmental monitoring in tropical mining landscapes.

This study examined the floristic composition, structural attributes, productivity, biomass, and conservation value of a tropical rainforest (TRF) in the Colombian Pacific region. A complete inventory of trees with DBH (Diameter at Breast Height) ≥ 10 cm was conducted, and analyses included diversity indices, species accumulation and rarefaction curves, structural parameters, productivity indices, and estimates of aboveground biomass and C (carbon) stocks. Multivariate analyses were also applied to evaluate beta diversity and flo-ristic dissimilarity among plots. The forest showed high species richness, with 45 species belonging to 26 families, and diversity indices confirmed a heterogeneous and balanced community. Structural analyses revealed a dense and complex stand with continuous re-generation, a reverse-J diameter distribution, and stratification dominated by lower and middle layers. Productivity indices highlighted the dual contribution of abundant small stems and a smaller number of dominant trees. Aboveground biomass reached very high values, corresponding to substantial C storage, with most of the pool concentrated in a few dominant taxa. Conservation analysis revealed that while most species were classified as Least Concern, four taxa were identified as threatened or vulnerable, and several remained unevaluated. Overall, the results confirm the dual role of TRFs as biodiversity hotspots and critical C reservoirs, underscoring the need for integrated conservation strategies.