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Losses of C and N from the forest floor and top 20-cm of soil were estimated following separate severe wildfires at two Long-Term Soil Productivity sites in the Sierra Nevada of California, USA. Experimental treatments applied 20 years prior to the wildfires included factorial combinations of 1) organic matter (OM) removal following clear-cut harvesting (SO, stem only harvest, WTH, whole-tree harvest, and WTH + FF, WTH plus the forest floor removal), 2) soil compaction (three levels of intensity), and 3) with and without understory vegetation control. Wildfires caused complete losses of the forest floor in all treatments and also oxidized varying portions of OM in the topsoil. As such, pre-fire forest floor measures were used as an estimate of forest floor C and N loss, and post-fire soil measures of C and N were compared to pre-fire soil data to estimate of mineral soil losses. Averaged over all treatments, the less-productive site that also had lesser accumulations of detritus (Wallace) lost 35.1 Mg C ha-1, or 25 % of its original C stores, while the more-productive site with greater detritus (Rogers) lost 18.4 Mg C ha-1, or 20 % of its original. The SO treatments that left harvest residue on site ended up with much greater losses of C: 36 % versus 15 and 17 % for WTH and WTH + FF, respectively. The SO also yielded the largest losses (25-30 %) of C in the top 10-cm of soil. The other treatments had smaller or inconsistent effects (understory vegetation control) or no effect (soil compaction). Our results suggest that potential benefits from SO by leaving residue on site to soil C and N accumulation can also be readily eliminated by wildfire which commonly occurs at these fire-prone forest ecosystems.

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Meeting food/wood demands with increasing human population and per-capita consumption is a pressing conservation issue, and is often framed as a choice between land sparing and land sharing. Although most empirical studies comparing the efficacy of land sparing and sharing supported land sparing, land sharing may be more efficient if its performance is tested by rigorous experimental design and habitat structures providing crucial resources for various species-keystone structures-are clearly involved. We launched a manipulative experiment to retain naturally regenerated broad-leaved trees when harvesting conifer plantations in central Hokkaido, northern Japan. We surveyed birds in harvested treatments, unharvested plantation controls, and natural forest references 1-year before the harvest and for three consecutive postharvest years. We developed a hierarchical community model separating abundance and space use (territorial proportion overlapping treatment plots) subject to imperfect detection to assess population consequences of retention harvesting. Application of the model to our data showed that retaining some broad-leaved trees increased the total abundance of forest birds over the harvest rotation cycle. Specifically, a preharvest survey showed that the amount of broad-leaved trees increased forest bird abundance in a concave manner (i.e., in the form of diminishing returns). After harvesting, a small amount of retained broad-leaved trees mitigated negative harvesting impacts on abundance, although retention harvesting reduced the space use. Nevertheless, positive retention effects on the postharvest bird density as the product of abundance and space use exhibited a concave form. Thus, small profit reductions were shown to yield large increases in forest bird abundance. The difference in bird abundance between clearcutting and low amounts of broad-leaved tree retention increased slightly from the first to second postharvesting years. We conclude that retaining a small amount of broad-leaved trees may be a cost-effective on-site conservation approach for the management of conifer plantations. The retention of 20-30 broad-leaved trees per ha may be sufficient to maintain higher forest bird abundance than clearcutting over the rotation cycle. Retention approaches can be incorporated into management systems using certification schemes and best management practices. Developing an awareness of the roles and values of naturally regenerated trees is needed to diversify plantations.

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Stand structure develops with stand age. Old-growth forests with well-developed stand structure support many species. However, development rates of stand structure likely vary with climate and topography. We modeled structural development of 4 key stand variables and a composite old-growth index as functions of climatic and topographic covariates. We used a hierarchical Bayesian method for analysis of extensive snap-shot National Forest Inventory (NFI) data in Japan (n = 9244) to account for differences in stand age. Development rates of structural variables and the old-growth index exhibited curvilinear responses to environmental covariates. Flat sites were characterized by high rates of structural development. Approximately 150 years were generally required to attain high values (approximately 0.8) of the old-growth index. However, the predicted age to achieve specific values varied depending on environmental conditions. Spatial predictions highlighted regional variation in potential structural development rates. For example, sometimes there were differences of >100 years among sites, even in the same catchment, in attainment of a medium index value (0.5) after timber harvesting. The NFI data suggested that natural forests, especially old natural forests (>150 years), remain generally on unproductive ridges, steep slopes, or areas with low temperature and deep snow, where many structural variables show slow development rates. We suggest that maintenance and restoration of old natural forests on flat sites should be prioritized for conservation due to the likely rapid development of stand structure, although remaining natural forests on low-productivity sites are still important and should be protected.

Un Modelo Empírico Espacialmente Explícito de Procesos de Desarrollo Estructural en Bosques Naturales Basado en el Clima y la Topografía Resumen La estructura de un rodal se desarrolla con la edad. Los bosques maduros con una estructura bien desarrollada dan sustento a muchas especies. Sin embargo, las tasas de desarrollo de los rodales probablemente varían con el clima y la topografía. Modelamos el desarrollo estructural de 4 variables clave de un rodal y un índice de crecimiento antiguo compuesto como funciones de covariables climáticas y topográficas. Utilizamos un método bayesiano jerárquico para analizar datos (n = 9,244) en fotografías del inventario nacional forestal (INF) de Japón para entender las diferencias en la edad de los rodales. Las tasas de desarrollo de las variables estructurales y el índice de crecimiento antiguo mostraron respuestas curvilíneas a las covariables ambientales. Los sitios planos se caracterizaron por altas tasas de desarrollo estructural. Por lo general, se requerían 150 años para alcanzar valores altos (∼0.8) en el índice de crecimiento antiguo. Sin embargo, la edad prevista para alcanzar valores específicos varió dependiendo de las condiciones ambientales. Las predicciones espaciales pusieron de relieve la variación regional en las potenciales tasas de desarrollo estructural. Por ejemplo, a veces había diferencia de >100 años entre sitios, aun en la misma cuenca, en el consecución de un valor de índice medio (0.5) después de la cosecha de madera. Los datos de INF sugieren que los bosques naturales, especialmente los bosques maduros (>150 años) permanecen generalmente en crestas improductivas, pendientes pronunciadas o en áreas con baja temperatura y nieve profunda, donde muchas variables estructurales muestran tasas de desarrollo lentas. Sugerimos que el mantenimiento y la restauración de bosques naturales maduros en sitios planos deben priorizarse para conservación debido al probable desarrollo rápido de la estructura del rodal, aunque los bosques naturales restantes en sitios de baja productividad también son importantes y deben ser protegidos.

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Abstract Montane forests are one of the most decimated of Neotropical biomes even though they provide a suite of valuable ecosystem services such as provision of water to lowland settlements and prevention of erosion and mudslides. In some instances, to restore these and other ecosystem services, degraded montane forests are replaced by exotic tree plantations, which cover sizeable areas in several countries. Despite their importance for assessment of ecological services and for intrinsic ecological value, comparative studies of paired native montane forest and conifer plantation are scarce along the Northern Andean Cordillera. Additionally, extrapolations are challenging because each pair of communities is highly site specific due to environmental setting, age and density of plantation, and reforestation species. Here, we assess and compare structure, biogeochemistry and ecosystem services provided by closely positioned native forest and pine plantation from a protected montane area in Venezuela. Soil nutrients and soil carbon content were 60 and 54 % respectively higher in the forest. As consequence of pine' growth form and leaf biochemistry, aboveground biomass and litter mass, as well as nutrient content and carbon stocks, were higher in the plantation. This results in the plantation storing 30 % more MgC ha-1 than the nearby forest. Canopy structure and litter properties influence the hydrology of both ecosystems through differences in rain throughfall. Most of the ecosystem services itemized are superior in the native forest, with exception that the younger plantation sequesters more carbon. An additional service provided by plantations might be that of ecological corridors that connect fragmented native forests. Our study, a specific case of nutrient and carbon cycling dynamics in paired montane forests and pine plantations, provides another set of data for the design of policy and management of considerable areas in the Neotropics with established conservation plantations.(AU)

Resumen Los bosques montanos son uno de los biomas más devastados del Neotrópico aunque proporcionan valiosos servicios ecológicos al suministrar agua a los asentamientos humanos y proteger contra la erosión y los deslaves. En algunas instancias, para mantener esos servicios ecológicos, los bosques destruidos son reemplazados por plantaciones forestales en áreas considerables de varios países. Aunque existen unos pocos estudios comparativos en a lo largo del norte de la Cordillera Andina, las extrapolaciones son difíciles debido a que estos son altamente específicos debido al entorno ambiental, edad de las plantaciones, y a la especie de conífera dominante. Nosotros analizamos y comparamos la diversidad y estructura de la vegetación, la biogeoquímica y los servicios ecológicos proporcionados por un bosque montano y una plantación de pino adyacente en un área protegida de Venezuela. Los suelos del bosque nativo contienen 60 % más de nitrógeno y 54 % más de carbono que los de la plantación. Como consecuencia de la forma de vida de los pinos y de su composición foliar, la biomasa aérea y el contenido de nutrientes en la hojarasca seca son mayores en la plantación dando como resultado que la plantación contiene 30 % MgC ha-1 más que el bosque. La estructura del dosel influencia la hidrología de ambos ecosistemas mediante diferencias en la penetración del agua de lluvia. La mayoría de los servicios son de menor valor ecológico en la plantación de pino. Sin embargo, esta ofrece servicios que no existirían en su ausencia. En regiones montañosas, las plantaciones de coníferas fueron establecidas para mejorar la provisión de agua y estabilizar los suelos. Sin embargo, nuestros resultados sugieren que las plantaciones pueden proporcionar corredores ecológicos que conecten bosques nativos fragmentados. Nuestro estudio, al proveer un ejemplo adicional de dinámica ecológica comparada, expone las diferencias en servicios ecológicos proporcionados por un bosque montano y una plantación de pino y proporciona información para establecer políticas de conservación y manejo de recursos naturales en extensas áreas neotropicales.(AU)

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BACKGROUND: Abandonment of broadleaved secondary forests that have been used for various purposes may cause the loss of biodiversity. Some of these forests suffer from diseases such as Japanese oak wilt. An increasing number of deer also impact some of them. Monitoring and recording the status of such forests is important for their proper management. NEW INFORMATION: This data set provides a concrete example of temporal changes in a temperate broadleaved secondary forest. The forest has been damaged by mass mortality of oak trees caused by Japanese oak wilt disease. In addition, the forest has been under foraging pressure by sika deer (Cervus nippon Temminck). The data set can provide information on how such a forest has changed in species composition of the canopy and sub-canopy layers and in species occurrence in the understory layer.

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Japanese macaques (Macaca fuscata) in their northernmost habitats represent a keystone species and play a central role in heavy snowfall ecosystems. However, distributions have been restricted by pre-war hunting, and populations are facing issues of natural forest losses caused by new dam constructions and massive conifer plantations. In the present study, we predicted the influences of these environmental conditions on macaque habitats during each season, and evaluated the effect of natural forest restoration as a mitigation measure. We constructed multiple habitat suitability models on the basis of different forest change scenarios, by using maximum entropy modeling (Maxent). We predicted the influence of each scenario by calculating the habitat unit (habitat quality × habitat quantity). We made the following predictions: (1) the influences of environmental conditions on habitat models vary seasonally, but dam construction destroys the optimum macaque habitats in every season; (2) restoration of conifer plantations to semi-natural forests does not always contribute to the improvement of total habitat unit, except in snowy seasons; and (3) in comparison with encouraging natural forest restoration in plantation areas and maintaining the standard-rotation plantation management, the implementation of long-rotation plantation in existing plantation areas provides more suitable alternative habitats for macaques in non-snowy seasons.

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