Forest harvesting can alter sedimentary processes in catchments by reducing vegetation cover and exposing the soil surface. To mitigate these effects, post-harvest residue management is commonly used, though its effectiveness needs individual evaluation. This study assessed how windrowed harvest residues influence structural sediment connectivity in two forest catchments in south-central Chile with a Mediterranean climate. Using digital terrain models and the Index of Connectivity, scenarios with and without windrows were compared. Despite similar windrow characteristics, effectiveness varied between catchments. In catchment N01 (12.6 ha, average slope 0.28 m m⁻¹), with 13.6% windrow coverage, connectivity remained unchanged, but in contrast, catchment N02 (14 ha, average slope 0.27 m m⁻¹), with 21.9% coverage, showed a significant connectivity reduction. A key factor was windrows’ orientation: 83.9% aligned with contour lines in N02 versus 58.6% in N01. Distance to drainage channels also played a role, with the decreasing effect of connectivity at 50–60 m in N02. Bootstrap analysis confirmed significant differences between catchments. These results suggest that windrow configuration, particularly contour alignment, may be more critical than coverage percentage. For effective connectivity reduction, especially on moderate to steep slopes, forest managers should prioritize contour-aligned windrows. This study enhances our understanding of structural sediment connectivity and offers practical insights for sustainable post-harvest forest management.

Eucalyptus plantations worldwide experience significant productivity losses due to herbivory caused by the weevil Gonipterus platensis (Coleoptera: Curculionidae. Marelli 1927); however, the role of leaf nutritional status in host preference remains poorly understood. In this study, we evaluated the incidence and severity of defoliation on two seed-propagated eucalypts—Eucalyptus globulus Labill. and Eucalyptus nitens Maiden, as well as two clonally propagated E. nitens × E. globulus hybrids—at a trial site in Mulchén, Chile. Sampling occurred after peak weevil activity (December 2022) and during austral autumn (May 2023). We determined foliar concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), boron (B), carbon (C), and the carbon-to-nitrogen (C/N) ratio, and analyzed their relationships with herbivory using ANOVA, principal component analysis (PCA), and linear regression. Overall defoliation was low (<7%), but significantly higher on E. globulus, with hybrids exhibiting intermediate damage. Seasonally, N and Mg concentrations declined, while K and Ca levels increased, resulting in an elevated C/N ratio in autumn. A positive correlation was observed between leaf Ca concentration and both the incidence and severity of herbivory during peak activity in the susceptible E. globulus genotype (R² = 0.96, p < 0.05). These findings suggest that calcium accumulation may influence weevil feeding preferences. Further research should explore nutrient-mediated resistance to guide selection and fertilization strategies for developing more resilient eucalyptus varieties.

Sustaining forest plantation productivity across successive rotations is increasingly challenging under changing environmental conditions. This study evaluated whether repeated establishment silviculture can maintain early second-rotation growth performance of Pinus radiata D. Don in central-south volcanic sandy soils in Chile. An experiment encompassing soil preparation (shovel planting vs. subsoiling + bedding), fertilization (B vs. NPKB), and weed control (pre-planting only vs. 2-year banded application) was conducted over two rotations. Survival, diameter, height, and stand-volume responses were compared between rotations at age 3. The second-rotation establishment period received 33% less annual rainfall than the first. Across all treatment combinations, mean survival decreased from 90.5% during the first rotation to 62.2% during the second rotation, while mean stand volume decreased from 6.58 to 1.16 m³ ha⁻¹. During the second rotation, weed control was the only treatment that significantly increased individual-tree and stand growth: plots receiving pre-planting weed control only averaged 38.7% survival and 0.29 m³ ha⁻¹, whereas those receiving additional 2-year banded vegetation control averaged 85.8% survival and 2.02 m³ ha⁻¹ stand volume. These findings indicate that vegetation control is key to sustaining P. radiata productivity. However, progressively unfavorable environmental conditions will jeopardize forest productivity across rotations.