Background: Understory plants represents the largest component of biodiversity in most forest ecosystems and plays a key role in forest functioning. Despite their importance, the influence of overstory-layer composition on understory plant diversity is relatively poorly understood within deciduous-evergreen broadleaved mixed forests. The aim of this work was to evaluate how tree overstory-layer composition influences on understory-layer diversity in three forest types (monospecific deciduous Nothofagus pumilio (Np), monospecific evergreen Nothofagus betuloides (Nb), and mixed N. pumilio-N. betuloides (M) forests), comparing also between two geographical locations (coast and mountain) to estimate differences at landscape level. Results: We recorded 46 plant species: 4 ferns, 12 monocots, and 30 dicots. Canopy-layer composition influences the herb-layer structure and diversity in two different ways: while mixed forests have greater similarity to evergreen forests in the understory structural features, deciduous and mixed were similar in terms of the specific composition of plant assemblage. Deciduous pure stands were the most diverse, meanwhile evergreen stands were least diverse. Lack of exclusive species of mixed forest could represent a transition where evergreen and deciduous communities meet and integrate. Moreover, landscape has a major influence on the structure, diversity and richness of understory vegetation of pure and mixed forests likely associated to the magnitude and frequency of natural disturbances, where mountain forest not only had highest herb-layer diversity but also more exclusive species. Conclusions: Our study suggests that mixed Nothofagus forest supports coexistence of both pure deciduous and pure evergreen understory plant species and different assemblages in coastal and mountain sites. Maintaining the mixture of canopy patch types within mixed stands will be important for conserving the natural patterns of understory plant composition in southern beech mixed forests.

Introduction: Variation in reproductive phenology among species is an important mechanism for maintaining species coexistence. In mixed forests, the impact of limiting (biotic and abiotic) factors on tree reproductive success regulates the maintenance of species in balanced proportions or the conversion towards monospecific forests. This study offer a significant first approach to the reproductive phenology of mixed forests, assessing flowering, seeding and loss factors on reproductive success in three forest types (pure deciduous Nothofagus pumilio (Np), evergreen Nothofagus betuloides (Nb) and mixed (M) forests), comparing also between two geographical locations (coast and mountain), during one growing season. Results: Flowering falling started early in Np. Seed fall occurred first and more concentrated in Np, while in Nb, it was progressive during autumn. Phenology in M combined both patterns, but with better reproductive performance of both species. Seed production was greater in Nb (42,900,000 ha

ResumenLos bosques subantárticos de las montañas fueguinas son consideradas una de las pocas áreas silvestres que quedan en el planeta; sin embargo, las perturbaciones humanas como incendios forestales, especies exóticas, etc. agravan su degradación. En 2012, se inició un incendio de origen humano en una remota zona de bosque y montaña, y dos años después comenzó un proyecto de reforestación para restaurar el dosel natural. Los renovales de la especie nativa de árbol Nothofagus se obtuvieron de zonas no perturbadas utilizando el método de raíz desnuda. En este estudio se evaluó la influencia de (1) los macroambientes (considerando la topografía natural y la fisonomía de la vegetación) y microambientes (topografía, cobertura del dosel, sustrato y cobertura del sotobosque) afectados por el fuego; y (2) el tamaño de extracción de los renovales (tamaño inicial), sobre la supervivencia y el crecimiento de los renovales plantados, a lo largo de 5 años. La supervivencia total de los renovales fue del 41,4%, con una tasa media de crecimiento de 8,46 cm año−1. La supervivencia y el crecimiento fueron influenciados por las variables estudiadas. A nivel de macroambiente, los renovales mostraron mayor éxito en zonas bien drenadas, mientras que a nivel de microambiente los renovales mostraron mejor desempeño en los que contribuyen a retener la humedad del suelo y evitar la evapotranspiración. Concluimos que las características ambientales influyen diferencialmente dependiendo de la escala de análisis. Para restaurar bosques templados quemados aplicando el método de repique directo a raíz desnuda, recomendamos utilizar renovales de Nothofagus de <40 cm de altura para obtener mejores resultados. En este sentido, demostramos la eficacia del método ya que se obtuvieron resultados comparables en otras experiencias de restauración. Este método también puede ser aplicado en áreas sin material de vivero y cuando la biología de las plantas sea apropiada, por ejemplo, el crecimiento superficial de los sistemas radiculares, la formación de bancos naturales de plántulas de árboles, etc. Este trabajo representa una de las pocas experiencias de restauración a medio plazo reportadas para los bosques más australes del planeta: nuestros hallazgos podrían ser aplicados en otras experiencias de reforestación, logrando mejoras notables en el proceso de recuperación.

The sub‐Antarctic forests in Tierra del Fuego mountains are considered one of the few remaining wilderness areas on the planet; however, human disturbances like wildfires, exotic species, and so forth exacerbate their degradation. In 2012, a human‐caused wildfire started in a remote forest‐mountain area, and 2 years after that, a reforestation project began to restore the natural canopy layer. Saplings of the native Nothofagus trees were obtained through the bare root method from undisturbed areas. In this study, we evaluated the influence of (1) macro‐ (considering natural topography and vegetation physiognomy) and micro‐environments (topography, canopy cover, substrate, and understory cover) affected by fire; and (2) the extraction size of the saplings (initial size), on survival and growth of planted saplings, over 5 years. Total sapling survival was 41.4% with a mean growth rate of 8.46 cm year−1. Survival and growth were influenced by the studied variables. At a macro‐environment level, tree saplings showed higher success in well‐drained zones, meanwhile at the micro‐environment level saplings performed better in those that contribute to retain soil moisture and avoiding evapotranspiration. We conclude that environmental features influence differentially depending on the scale of analysis. To restore burnt temperate forests applying the bare root method, we recommended using Nothofagus saplings <40 cm tall for better results. In this sense, we demonstrated the effectiveness of the method since comparable results were obtained in other restoration experiences. This method can also be applied in areas without nursery material, when the biology of tagged plants was appropriated, for example shallow growth of root systems, formation of natural tree seedling banks. This work represents one of the few medium‐term restoration experiences reported for the southernmost forests of the planet: our findings could be applied in other reforestation experiences, making noticeable improvements in the recovery process.