Despite the great diversity of tree species in the Neotropics, most commercial reforestation efforts in this region continue to rely on exotic species. Over the past few decades, with the aim of promoting the use of native species such as Retrophyllum rospigliosii, experimental plantations have been established in the tropical Andes to assess their viability for commercial reforestation projects. In the tropical Andes of Colombia, topography generates substantial variation in microclimate, water availability, and soil conditions, which can influence tree growth and plantation productivity. Thus, we evaluated how topography influences the growth of R. rospigliosii by estimating its site index using an array of topographic variables at multiple spatial scales. We measured height growth of individual trees in 30 permanent plots in a 20 year-old plantation, and nine topographic variables using a high-resolution digital elevation model. We estimated the site index for R. rospigliosii using the Bertalanffy model (R2 > 98
Plantation forestry underpins rural livelihoods, wood and energy security and landscape restoration in Ethiopia, yet the country lacks a forestry-specific climatic classification to support species deployment and plantation planning. This study developed the first national climatic classification framework for exotic plantation forestry in Ethiopia by integrating temperature and a temperature-adjusted moisture index and quantifying regional temperature–elevation relationships. Mean annual temperature from WorldClim was classified into six forestry-relevant classes, while regional models quantified lapse-rate variability and corresponding elevation equivalents. Moisture availability was represented by the ratio of mean annual precipitation to mean annual temperature (MAP/MAT), providing a simple, spatially consistent measure of precipitation relative to thermal conditions rather than a mechanistic water-balance index. The framework was used to classify plantation environments, quantify climatic potential for plantation forestry and assess the climatic suitability of selected Eucalyptus, Corymbia and Acacia species using published thresholds. Temperature–elevation relationships varied substantially among regions, demonstrating the limitations of a single national lapse rate. Approximately 31
Recent work demonstrated that phosphorus (P) fertilization and chemical root pruning (RP) during nursery production of Aristotelia chilensis and Quillaja saponaria, two important tree species in the mediterranean region of Chile, affected root architecture and nutritional status. Here we report on how the nursery-induced modifications through P fertilization and RP influence post-transplanting root growth potential (RGP) and drought tolerance. RGP was quantified through the number, length, and biomass of newly formed roots, while leaf water potential (ΨL) and stomatal conductance were monitored during a controlled drought experiment. Higher P fertilization enhanced CO₂ assimilation, water-use efficiency, and RGP in both species. It also promoted species-specific drought strategies: A. chilensis displayed a more isohydric response, tightly regulating water loss, whereas Q. saponaria maintained gas exchange under declining ΨL, reflecting anisohydric behavior. In contrast, RP reduced RGP and impaired drought performance by limiting new root development and restricting gas exchange. These results highlight the positive role of P fertilization in producing drought-resilient plants and question the suitability of RP for mediterranean woody species intended for restoration. Understanding how nursery practices shape morpho-physiological and root traits is essential to optimize plant quality and post-planting survival under increasingly frequent drought conditions.
Chitosan is increasingly recognized as a promising biostimulant and potential biocontrol-related elicitor in forestry, yet its effectiveness under biotic stress remains underexplored. In this study, the effects of chitosan on photosynthetic pigments and secondary metabolites in pine (Pinus sylvestris L.) seedlings representing five genetic families were investigated, both in the absence of pathogens and following inoculation with Heterobasidion annosum (HA) or Lophodermium seditiosum (LS). Treatments varied by solvent formulation (water or acetic acid) and concentration (0, 2, or 10 g/L). In the absence of a pathogen, chitosan responses were strongly dependent on genotype and dose, with lower concentrations (2 g/L) often producing favourable changes in chlorophyll (e.g., in the 5J genetic family, chlorophyll concentration ranged from 154.49 mg/g (0 g/L) to 205.54 mg/g (2 g/L)) or secondary metabolite accumulation, while higher doses showed diminishing or genotype-specific returns. Solvent formulation had a secondary but detectable influence. Following pathogen inoculation, chitosan treatment altered pigment and secondary metabolite profiles relative to inoculated controls, with several genotype–treatment combinations showing higher chlorophyll, carotenoid, phenolic, or flavonoid concentrations. However, these responses were not uniform across families, pathogens, solvents, or concentrations. Overall, the findings indicate that Scots pine seedlings exhibit genotype-dependent physiological and biochemical responsiveness to chitosan under pathogen-associated stress. These results should be interpreted as evidence of treatment-associated physiological responses rather than confirmed disease protection. The strong influence of genotype and concentration in this pilot study highlights the need for further mechanistic and field-based studies before chitosan application strategies can be generalized.
Saba senegalensis is a multipurpose indigenous tropical liana of high ecological and socioeconomic importance in West Africa. Its declining natural populations, together with limitations of seed-based propagation, highlight the need for efficient vegetative propagation strategies. This study investigated the interactive effects of season and exogenous growth regulators on adventitious rooting and nursery establishment of air-layered S. senegalensis. A total of 450 air layers were established during cold (Temperature 24.93 ± 1.86 °C and Relative humidity 27.25 ± 6.33
