The Eucalyptus grandis × E. urophylla hybrid is characterized by its rapid growth and high productivity, which has led to an increasing demand for its propagation in nurseries. To preserve these desirable traits, it is essential to establish clonal gardens and apply effective clonal propagation methods. With the aim of advancing knowledge on asexual propagation techniques, this study evaluates the influence of indole-3-butyric acid (IBA) and a commercial formulation combining IBA and naphthaleneacetic acid (NAA) on the rooting and root development of cuttings of this hybrid. To achieve this, cuttings were collected from a clonal garden and subjected to five rooting treatments: T0 (control) with 0 ppm IBA; T1 with 1,000 ppm IBA; T2 with 1,500 ppm IBA; T3 with 2,000 ppm IBA; and T4, a commercial formulation containing 4,000 ppm NAA and 1,000 ppm IBA. The experiment was conducted under a completely randomized design (CRD) with 90 experimental units. After treatment application, the cuttings were placed in a greenhouse for 30 days. At the end of this period, rooting percentage, mortality rate, number of roots, root length, and root dry weight were assessed. The results indicated that T2 and T4 exhibited the best performance in terms of rooting and root development. Furthermore, comparison with other studies revealed that excessively high concentrations of IBA can exert toxic effects on cuttings. Overall, the study concludes that IBA, either alone or in combination with NAA, positively influences the rhizogenesis process of Eucalyptus grandis × E. urophylla cuttings, increasing rooting percentage by up to 62% compared to the control.
Assessing climate vulnerability of tropical trees requires ecological niche modeling frameworks capable of integrating multiple sources of uncertainty. Here, we present an integrated modeling approach that combines climatic, edaphic, and topographic predictors, dimensionality reduction, multi-algorithm calibration, and ensemble forecasting to evaluate future environmental suitability under climate change. Using two Brazilian Handroanthus species as a case study, occurrence data were spatially filtered, predictors were summarized through principal component analysis, and models were built using six algorithms with performance-weighted consensus projections. Future distributions were projected for three time periods (2041–2060, 2061–2080, and 2081–2100) under intermediate and high emission scenarios (SSP2-4.5 and SSP5-8.5). The framework showed high predictive reliability and revealed contrasting vulnerability patterns, including severe suitability losses for one species and greater stability for the other across phytogeographic domains. Beyond species-specific outcomes, results demonstrate how integrated Ecologial Niche Modeling (ENM) frameworks can identify climate-driven risk gradients and support climate-informed conservation, forest management, and territorial planning in tropical regions.
The Mediterranean region faces increasing aridity due to climate change, threatening the establishment and growth of drought-sensitive tree species. The ecologically and economically important mastic tree generally exhibits drought resilience but remains vulnerable to heightened water stress due to climate change. This study evaluated the effectiveness of crescent bunds, a rainwater harvesting (RWH) system, in enhancing the growth and survival of young mastic (Pistacia lentiscus L. var. chia) tree seedlings in a previously established (three-year-old) plantation in the semi-arid Urla-Çeşme Peninsula, Izmir, western Türkiye. Two treatments were compared: traditional pit planting (the control) and crescent bunds. Two-meter-diameter crescent bunds were formed around three-year-old seedlings to capture runoff. The control treatment included the seedlings pit-planted three years ago. No significant differences were observed between the RWH and the control treatments one-year post-treatment. However, two years after treatment, the seedlings with crescent bunds exhibited significantly greater increases in mean height (15%), root-collar diameter (19%), and crown diameter (35%) than the controls. The sturdiness index remained similar between treatments, indicating balanced growth. Relative growth metrics revealed that crescent bunds supported at least a threefold increase in height and crown diameter growth over the control. These findings highlighted the potential of crescent bunds to improve soil moisture availability and enhance long- term seedling performance in water-limited environments. The study underscored the importance of adaptive and sustainable water management techniques, such as RWH systems, for sustaining mastic tree plantations under climate change-induced aridity, offering scalable solutions for Mediterranean afforestation.
High-density willows plantations are used for biomass production in several countries, but in Argentina, information about the adequate management for such plantations is scarce. This fact hinders the development of commercial plantations that could reduce the country dependence on fossil energy. The aim of this work was to analyse the productivity of a willow Short Rotation Coppice (SRC) plantation and to identify potential and actual biomass yields under local conditions. Our hypothesis was that water availability was major limitation for biomass yield in the area, so this factor was included in the trial design. The trial was planted in an agricultural soil in the Rolling Pampas region of Central Argentina, and its yield was measured for a period of 10 years. The factors analysed were irrigation (drip irrigation and rainfed), planting density (13,300 and 20,000 plants ha-1) and two genotypes: Salix alba and a S. matsudana × S. alba hybrid. The trial was disposed in a split-split plot design, and the rotation length was one year. The irrigated treatment consistently produced more than the rainfed one, the yield of irrigated treatment ranged between 10.4-22.6 MG ha-1, and between 2.9-17.6 MG ha-1 for rainfed plots. Yield correlated with water supply during the summer months (rs = 0.79). Biomass production was high in the first four years, but afterwards, yield steadily declined, both in irrigated and rainfed treatments. According to our results, to develop biomass SRC plantations with willows in Central Argentina, irrigation would be necessary during the summer months.
Active restoration strategies are crucial for accelerating forest recovery in highly degraded landscapes within the Araucaria Forest. This study evaluated the effects of two different spatial arrangements: Anderson nuclei and mixed planting on the dendrometric performance of three representative native species (Mimosa scabrella, Araucaria angustifolia, and Solanum diploconos). Data were collected 45 and 57 months after planting and analyzed using multivariate tests (MANOVA) and univariate comparisons. The results showed significant effects of treatments, species, and their interactions on height, diameter at ground level, and canopy projection. Mimosa scabrella, a fast-growing pioneer species, maintained structural dominance across all treatments and years. Araucaria angustifolia, a mid- to late-succession species, showed modest growth in 2023 but responded significantly in 2024, particularly in the Anderson nuclei. Solanum diploconos showed consistently lower values, but with gradual increases, compatible with its shade-tolerant understory niche. Comparisons between the arrangements indicated that the Anderson cores promoted more pronounced facilitation effects, favoring the growth performance of mid- and late- successional species and accelerating canopy closure. At the same time, mixed planting resulted in more homogeneous but less expressive growth patterns. The Anderson’s core technique is an ecologically sound alternative to mixed plantings, as it combines the rapid growth of pioneer species with the creation of a facilitative environment, accelerating the succession process and helping achieve restoration objectives more efficiently.
The reproductive biology of Byrsonima pachyphylla and B. verbascifolia in the Brazilian state of Tocantins in the Cerrado biome (Savanna) is described unprecedentedly in this work. This genus belongs to the Malpighiaceae family, which is one of the main sources of resources for bees. Inflorescences of each species were collected for analysis of morphometry and other floral characteristics at Fazenda São Judas Tadeu (10° 48’ 31’’ S and 48° 26’ 52’’ W), located in the municipality of Porto Nacional, Tocantins, Brazil. Floral visitors were observed directly in the field during the peak flowering period. The analysis of the reproductive system was carried out through manual cross-pollination, manual self-pollination, spontaneous self-pollination, apomixis, and natural pollination (control group). The floral characteristics are related to the melittophily syndrome. The bees Centris aenea, C. fuscata, C. sponsa, and C. vittata, were the effective pollinators. Trigona spinipes, Xylocopa frontalis, X. suspecta, Epicharis flava, Augochlora mendax and Apis mellifera performed occasional and sternotribic pollination. Reproductive tests of B. pachyphylla showed fruiting success of 40% by manual cross-pollination and 53% by natural pollination (control group), while through spontaneous self-pollination, manual self-pollination and apomixis there was no reproductive success. For B. verbascifolia, 33% of fruits formed by spontaneous self-pollination, 43% by manual self-pollination, 60% by manual cross- pollination and 63% in the control group, while by apomixis there was no reproductive success. B. pachyphylla is self-compatible and B. verbascifolia is self-incompatible and they both depend on pollinators to ensure their reproductive success.
Rainfall interception plays a key role in regulating water inputs in semi-arid Mediterranean ecosystems. This study evaluated rainfall redistribution under Vachellia caven (native shrubland) and Persea americana (orchard) in central Chile using rainfall simulations at two intensities (8 and 25 mm h⁻¹). Throughfall (TF), stemflow (SF), and interception (I) were measured in three individuals per species. Rainfall intensity was the main factor controlling redistribution, with significantly higher TF and net precipitation under high intensity (P < 0.01). Interception tended to be higher in V. caven (up to 87%) than in P. americana, although differences were not statistically significant. Stemflow contributed less than 1% of total precipitation in both species. These results highlight the dominant role of rainfall intensity over species traits in rainfall partitioning, with implications for soil water inputs and hydrological processes in semi-arid environments.
Large and old trees are key structural components of old-growth temperate forests, yet their persistence under uneven-aged silvicultural systems remains poorly resolved. In many regions, single-tree selection is promoted as a close-to-nature management approach intended to maintain structural complexity, but its long-term consequences for large-diameter tree cohorts remain insufficiently evaluated. We evaluated the effects of repeated single-tree selection on large-diameter tree retention in the Hyrcanian temperate forests (northern Iran) using a landscape-scale case study from the Kheyrud Experimental Forest. Our analysis combined (i) a temporal comparison of permanent inventory plots before harvesting (1982) and after three decades of management (2010) with (ii) a comparison between managed district and adjacent unlogged reference forest, based on a complete inventory covering approximately 1,600 ha. Tree frequency and diameter structure were analyzed with emphasis on large (DBH ≥ 100 cm) and giant (≥ 150 cm) trees. Large-tree density in the managed district declined by 58%, while giant-tree density declined by 83% between 1982 and 2010. Diameter-class distributions further revealed a pronounced truncation of upper-diameter cohorts, whereas stem densities in smaller size classes remained broadly comparable between inventories. In 2010, large-tree density in the managed district remained 63% lower than in the unlogged reference forest. These results indicate that single-tree selection, as implemented in this system, did not maintain the large-tree structure characteristic of mature Hyrcanian forests. Maintaining these structural legacies likely requires explicit retention thresholds for very large trees, longer cutting cycles, and permanent no-harvest areas within managed forest landscapes.
Climate change is expected to drive significant shifts in species distributions, particularly in temperate forest ecosystems. Areas of long-term environmental stability, known as climatic refugia, may play a key role in preserving biodiversity under future climate scenarios. This study assessed the potential impact of climate change on the distribution of eleven temperate forest tree species in Oaxaca, Mexico. Species distribution models were developed for eleven tree-species of temperate forest using Random Forest, Generalized Additive Models, and Generalized Linear Models. Among these, Random Forest achieved the highest predictive performance. Future distributions were projected under two shared socioeconomic pathways (SSP126 and SSP585) for 2040 and 2100. Results indicate that under the SSP585 scenario, all species could lose over 90% of their current potential range by 2100. Although some are classified as “Least Concern” by the IUCN (2024), their local vulnerability is pronounced. Additionally, projections suggest declining representation within Natural Protected Areas, raising concerns about their long-term conservation capacity. These findings highlight the urgency of implementing adaptive conservation measures, including the identification and management of climatic refugia, promotion of assisted migration, and reduction of anthropogenic pressures to enhance species resilience.
