Araucaria araucana forests in the southern Andes are heavily used for livestock grazing, yet the joint responses of stand structure, regeneration, and genetic diversity to grazing exclusion are not well understood. We used a 15-year natural experiment in the Ralco National Reserve (Chile) comparing a fenced, ungrazed site with an adjacent grazed site. We integrated data from 16 forest plots, four regeneration transects (128 subplots), and amplified fragment length polymorphism (AFLP) markers to assess changes in the two tree species present (A. araucana and Nothofagus obliqua), which jointly constitute 100

This paper reviews the current knowledge of hydrological processes in Chilean temperate forests which extend along western South America from latitude 29 degrees S to 56 degrees S. This geographic region includes a diverse range of natural and planted forests and a broad sweep of vegetation, edaphic, topographic, geologic, and climatic set-tings which create a unique natural laboratory. Many local communities, endangered freshwater ecosystems, and downstream economic activities in Chile rely on water flows from forested catchments. This review aims to (i) provide a comprehensive overview of Chilean forest hydrology, to (ii) review prior research in forest hydrology in Chile, and to (iii) identify knowledge gaps and provide a vision for future research on forest hydrology in Chile. We reviewed the relation between native forests, commercial plantations, and other land uses on water yield and water quality from the plot to the catchment scale. Much of the global understanding of forests and their relationship with the water cycle is in line with the findings of the studies reviewed here. Streamflow from forested catchments increases after timber harvesting, native forests appear to use less water than plantations, and streams draining native forest yield less sediment than streams draining plantations or grassland/shrublands. We identified 20 key knowledge gaps such as forest groundwater systems, soil-plant-atmosphere interactions, native forest hydrology, and the effect of forest management and restoration on hydrology. Also, we found a paucity of research in the northern geographic areas and forest types (35-36 degrees S); most forest hydrology studies in Chile (56%) have been conducted in the southern area (Los Rios Region around 39-40 degrees S). There is limited knowledge of the geology and soils in many forested areas and how surface and groundwater are affected by changes in land cover. There is an opportunity to advance our understanding using process-based investigations linking field studies and modeling. Through the establishment of a forest hydrology science "society" to coor-dinate efforts, regional and national-scale land use planning might be supported. Our review ends with a vision to advance a cross-scale collaborative effort to use new nation-wide catchment-scale networks Long-term Ecosystem Research (LTER) sites, to promote common and complementary techniques in these studies, and to conduct transdisciplinary research to advance sound and integrated planning of forest lands in Chile.

<p>The phenomena associated with global climate variability may lead to more intense extreme events, thus causing an increase in floods and prolonged droughts. In view of this situation, the Chilean Directorate of Hydraulic Works (DOH) has the task of selecting the works to be executed with the highest priority with the annual budget, to control and mitigate the effects of floods. Hence the need for a tool that includes the evaluation of fluvial morphodynamics, which allows the management of hydraulic works compatible with the processes of response and adjustment of the channels. The objective of this study is to characterize the fluvial styles of the Duqueco River based on its geomorphology, to understand the character and behavior of the fluvial corridor in a semi-automatic way applying GIS techniques and Python geoprocessing. The first stage of the River Styles framework is applied through the South Rivers Toolbox program, which characterizes and classifies fluvial styles based on hydromorphological attributes measured at segment scale, implementing a semi-automatic approach that reduces expert judgment. Previously, the disaggregation and aggregation framework is used, which determines channel attributes at a local scale, and then aggregates them with a statistical test in larger reaches. The whole process is performed in a semi-automated way with tools from the South Rivers Toolbox set within the QGIS software. As results, 36 main fluvial styles and 47 complementary styles are classified and characterized, and the river channel is analyzed in 3 zones. The upper zone is characterized by being mostly confined, mono-channel, with a bed of boulders and blocks, being highly intervened by power generation works; the middle zone is still mostly confined and mono-channel, with a change in the type of bed towards boulders. Finally, the lower zone is more diverse in styles, mostly unconfined, with a high presence of geomorphic units that give way to multichannel and transition zones.</p>

We used the lumped rainfall–runoff hydrologic models Génie Rural à 4, 5, 6 paramètres Journalier (GR4J, GR5J and GR6J) to evaluate the most robust model for simulating discharge on four forested small catchments (<40 ha) in south-central Chile. Different evapotranspiration methods were evaluated: Oudin, Hargreaves–Samani and Priestley–Taylor. Oudin’s model allows the achievement of the highest efficiencies in the flow simulation. The more sensitive parameters for each model were identified through a Generalized Probability Uncertainty Estimation (GLUE) model. Our results demonstrate that the three hydrological models were capable of efficiently simulating flow in the four study catchments. However, the GR6J model obtained the most satisfactory results in terms of simulated to measured streamflow closeness. In general, the three models tended to underestimate peak flow, as well as underestimate and overestimate flow events in most of the in situ observations, according to the probability of non-exceedance. We also evaluated the models’ performance in a simulation of summer discharge due to the importance of downstream water supply in the months of greatest scarcity. Again, we found that GR6J obtained the most efficient simulations.

Araucaria araucana is an iconic long-lived endangered tree species exclusively distributed in Southern Chile and Argentina. Araucaria forest ecosystems provide a myriad of ecosystem benefits to local aboriginal Mapuche-Pehuenche communities. Among the main current threats for Araucaria forests are the increasing frequency and severity of wildfires and overgrazing. This study evaluates the effect of uncontrolled livestock grazing on soil quality indicators linked to critical functions relevant to forest regeneration and ecosystem service provision. We also aim to determine a set of soil quality indicators that are sensitive enough to grazing pressure, so they are useful as early indicators of degradation or the effectiveness of restoration practices. This study evaluated twenty soil quality indicators in two contiguous degraded forest areas with contrasting grazing pressure. We observed a substantial shift in forest structure, a reduction in tree coverage on the overgrazed sites. Overgrazing has produced significant deterioration of most soil physical, chemical, and biological quality indicators making soil conditions less suitable for seed germination and sapling establishment. We also observed an alteration in C, N, and P biogeochemical pools. Besides, soil physical indicators alterations suggest changes in these soils’ hydrological behavior, potentially reducing water storage, availability, and increasing runoff. We show that uncontrolled grazing in native protected areas degrades soils and forest health, restricting forest regeneration and potentially accelerating erosive processes. Our results emphasized the need for an improved conservation plan for these forests that systematically evaluates and monitors livestock grazing and all its direct and indirect effects, including soil quality.

Araucaria araucana is an iconic long-lived endangered tree species native to Southern Chile and Argentina. Araucaria forests and soils provide a myriad of ecosystem benefits to local communities, which are threatened by increasing anthropic-driven disturbances like fire and livestock overgrazing. The main objectives of this study were: (i) to evaluate the effect of uncontrolled livestock grazing on soil health; and (ii) to identify a set of sensitive soil health indicators to grazing pressure. Twenty soil health indicators in two contiguous degraded forest areas with contrasting grazing pressure were considered. A substantial shift in forest structure and a 12% reduction in tree coverage on the overgrazed sites were observed. Overgrazing has substantially affected soil physical, chemical, and biological health indicators, making soil conditions less suitable for forest regeneration. Significant increments in C:P and N:P ratios were observed due to overgrazing (p < 0.01). Soil chemical properties such as Kjeldahl nitrogen, P-fractions (total, inorganic, and available), cation exchange capacity (CEC), and pH were identified as the best indicators of overgrazing activity in these soils. Additionally, forest cover reduction and overgrazing altered soil physical indicators (e.g., saturated hydraulic conductivity, infiltration, and aggregate stability), suggesting changes in hydrological behavior with potential consequences in water storage and availability. Our results show that uncontrolled grazing in native protected forests degrades soils and forests, restricting forest regeneration and potentially accelerating erosive processes. These results emphasize the need for improved conservation plans for these endangered forests that systematically evaluates and monitors the direct and indirect effects of livestock grazing on soil health.

Se estima la función de emparejamiento para el mercado laboral chileno con eficiencia variante en el tiempo y corrigiendo por sesgo de endogeneidad para el período 1986-2015. Los resultados encontrados son consistentes, significativos y muestran la existencia de un quiebre estructural alrededor del 2002 y una elasticidad de la rigidez del mercado laboral de 11,68% antes del quiebre y de 12,53% después del mismo.

Nothofagus species behave like early successional species that recolonize open sites after of regular and large-scale disturbances. This study analyzed the effects of light regimes on patterns of advanced regeneration dynamics, growth in diameter and height of Nothofagus dombeyi (Mirb.) Oerst. (Density of 240 trees ha(-1), basal area of 56.7 m(2) ha(-1)). Systematic sampling every 50 m in three stands (7.5 ha) was used. At each point and with the same center, two concentric circular plots were established, 9.0 m and 1.8 m radius. For estimate solar radiation transmissivity in plots, a solariscope hemispheric photographic camera was used. Diameters at breast height and basal areas (BA), heights (H) were measured and then counted and measured N. dombeyi seedlings and saplings. 13 saplings of advanced regeneration were harvested from all gaps to obtain age (E), total height (TH), absolute radial growth (ARG), and absolute height growth (AHG). As results, solar radiation varied between 3 and 40%. ARG varied between 1.20 and 2.22 mm yr(-1) and AHG between 0.15 and 0.43 m yr(-1). We found correlation for ARG and AHG with direct and global solar radiation transmissivity, but not with diffuse solar radiation transmissivity. The plant age and transmittance of direct and global solar radiation explains the increases in diameter and height. However, in our study stated that in the Andean region of south-central Chile, N. dombeyi stands is affected by small-scale disturbances. Therefore, transmissivity radiation solar inside the forest, explaining natural regeneration patterns and growth of N. dombeyi.

A field study using satellite images was carried out to analyze the effect of coastal vegetation in mitigating the impact of a catastrophic tsunami on coastal villages in the Biobío Region, Chile, in February 2010. Two types of stand, Pinus radiata D. Don forests and Cupressus macrocarpa Hartw. shelterbelts, appear to have protected coastal areas behind them from the direct impact of the tsunami. The impacts of the horizontal and vertical structures of these coastal forests on the drag forces were analyzed by observing the characteristics of Pinus radiata forests and Cupressus macrocarpa shelterbelts. The stands absorbed the impact of the tsunami without incurring broken stems or uprooted trees due to their diverse horizontal structure, as they contained short trees with various diameters. However, small areas of the stands were damaged by salinity after the tsunami. For this tsunami, which was less than 3 m high, the horizontal and vertical structures of the P. radiata and C. macrocarpa stands provided effective protection for coastal villages since they reduced the velocity and height of the tsunami. A shelterbelt consisting of three rows of C. macrocarpa in front of the tsunami and a P. radiata forest with a density of 11 trees/100 m2 and a width of >50 m immediately behind the shelterbelt are suggested as a means of protecting communities along the coastline of the Biobío Region against tsunamis.

File List baad.zip (MD5: 0a365cf79ab562a7985c426668fbc2a1) baad_data.zip (MD5: b9bc52c53be65506696a02862999ad9e) Description Understanding how plants are constructed; i.e., how key size dimensions and the amount of mass invested in different tissues varies among individuals; is essential for modeling plant growth, estimating carbon stocks, and mapping energy fluxes in the terrestrial biosphere. Allocation patterns can differ through ontogeny, but also among coexisting species and among species adapted to different environments. While a variety of models dealing with biomass allocation exist, we lack a synthetic understanding of the underlying processes. This is partly due to the lack of suitable data sets for validating and parameterizing models. To that end, we present the Biomass and allometry database (BAAD) for woody plants. The BAAD contains 259 634 measurements collected in 176 different studies, from 21 084 individuals across 678 species. Most of these data come from existing publications. However, raw data were rarely made public at time of publication. Thus the BAAD contains individual level data from different studies, transformed into standard units and variable names. The transformations were achieved using a common workflow for all raw data files. Other features that distinguish the BAAD are: (i) measurements were for individual plants rather than stand averages; (ii) individuals spanning a range of sizes were measured; (iii) inclusion of plants from 0.01–100 m in height; and (iii) biomass was estimated directly, i.e., not indirectly via allometric equations (except in very large trees where biomass was estimated from detailed sub-sampling). We included both wild and artificially grown plants. The data set contains the following size metrics: total leaf area; area of stem cross-section including sapwood, heartwood, and bark; height of plant and crown base, crown area, and surface area; and the dry mass of leaf, stem, branches, sapwood, heartwood, bark, coarse roots, and fine root tissues. We also report other properties of individuals (age, leaf size, leaf mass per area, wood density, nitrogen content of leaves and wood), as well as information about the growing environment (location, light, experimental treatment, vegetation type) where available. It is our hope that making these data available will improve our ability to understand plant growth, ecosystem dynamics, and carbon cycling in the world's vegetation. Key words: allometric equations; biomass allocation; biomass partitioning; global carbon cycle; plant allometry; plant traits.

Understanding how plants are constructed—i.e., how key size dimensions and the amount of mass invested in different tissues varies among individuals—is essential for modeling plant growth, carbon stocks, and energy fluxes in the terrestrial biosphere. Allocation patterns can differ through ontogeny, but also among coexisting species and among species adapted to different environments. While a variety of models dealing with biomass allocation exist, we lack a synthetic understanding of the underlying processes. This is partly due to the lack of suitable data sets for validating and parameterizing models. To that end, we present the Biomass And Allometry Database (BAAD) for woody plants. The BAAD contains 259 634 measurements collected in 176 different studies, from 21 084 individuals across 678 species. Most of these data come from existing publications. However, raw data were rarely made public at the time of publication. Thus, the BAAD contains data from different studies, transformed into standard units and variable names. The transformations were achieved using a common workflow for all raw data files. Other features that distinguish the BAAD are: (i) measurements were for individual plants rather than stand averages; (ii) individuals spanning a range of sizes were measured; (iii) plants from 0.01–100 m in height were included; and (iv) biomass was estimated directly, i.e., not indirectly via allometric equations (except in very large trees where biomass was estimated from detailed sub-sampling). We included both wild and artificially grown plants. The data set contains the following size metrics: total leaf area; area of stem cross-section including sapwood, heartwood, and bark; height of plant and crown base, crown area, and surface area; and the dry mass of leaf, stem, branches, sapwood, heartwood, bark, coarse roots, and fine root tissues. We also report other properties of individuals (age, leaf size, leaf mass per area, wood density, nitrogen content of leaves and wood), as well as information about the growing environment (location, light, experimental treatment, vegetation type) where available. It is our hope that making these data available will improve our ability to understand plant growth, ecosystem dynamics, and carbon cycling in the world's vegetation.

This work presents the willingness to pay of smallholders of the rainfed from Central Chile by means of implementing restoration projects of soils degraded by erosion, covering an area that extends from Libertador Bernardo O'Higgins Region to Biobio Region. In order to determine the extent of welfare in smallholders by means of the application of soil restoration projects, the Contingent Valuation Method was used. This model assumes the linear functional form of an indirect function of usefulness and a logical distribution for the method of stated preferences in the format of a simple dichotomous model. The determinant variables of the willingness to pay that were significant were evaluated. These variables were the condition of the owner and the perception of low performance derived from the erosion condition of the land, unlike variables such as yields, expenses or costs which can be due to the perception as such in the economy of the smallholder who lives off the land. As welfare measurement the trimmed means was measured, resulting in 7.17 US$ ha(-1) and adding -to the total surface of the inland rainfed- of 2,463,761 US$ per month.

This study developed a stand density management diagrams using an allometric size-density relationship, based only permanent plots from the Biobio region and to provide a regional tool to allow a better quantitative control of the intermediate cut in roble (Nothofagus obliqua). We used 20 fragments of pure roble located at different environments in the region of Biobio. To get mortality initiation line and the maximum stand production initiation line, were used theoretical estimates of relative density of 0.60 and 0.40 respectively in relation to the maximum size-density line. In our study, the slope of size-density relationships and maximum size-density line differs significantly from the value determined by other studies developed for roble in the country. Furthermore, the slope of size-density relationships was more negative in the Biobio region for roble, and is indicative of lower growth rates and lower site productivity. It justifies develop models of stand density management diagrams considering specific ecological zones for the same species; furthermore it is necessary to standardize methodologically these studies.

© 2012 Rodriguez and Real, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Use of GIS to Estimate Productivity of Eucalyptus Plantations: A Case in the Biobio Chile’s Region

A simplified, physiologically based (3-PG) model was used to evaluate the effects of spatial variation in climate and soils on the potential productivity of Eucalyptus nitens Deane and Maiden (Maiden). The model was parameterized based on the physiology of E. nitens to predict potential productivity and leaf area index as influenced by environmental factors. Data obtained from conventional weather stations were utilized by the 3-PG model to predict productivity site classes. A final plantation suitability grid was mapped to show areas of the region with productivity classes predicted to be very high (> 52 m(3) ha(-1) year(-1)), high (47.5-52 m(3) ha(-1) year(-1)), moderate (45-47.5 m(3) ha(-1) year(-1)), low (35-45 m(3) ha(-1) year(-1)) and very low (< 35 m(3) ha(-1) year(-1)). The lowest potential productivity was attributable to soil water and nutrients limitations. A process-based forest growth model that can be widely extrapolated using geographic information system is particularly useful to screen areas as prospective plantation sites.

The effect of silvicultural regime, tree size and competitive status on needle mass, root fine production and allocation of carbon to stem wood was analyzed. Three stands with different agroforestry treatments were compared with one managed traditionally. Data were obtained through destructive sampling of 36 trees and analyzed by ANOVA and regression analysis. The analysis allowed us to conclude that foliage mass was not affected by the silvicultural treatment, tree size or competitive status. Fine root biomass showed an inverse relationship with fertilization. Growth efficiency was not affected by the management treatment, tree size, or intraspecific competition. The greater stem wood allocation recorded in the agroforestry treatment than in the forestry regime, is interpreted as a response to two different types of competition. Competition for light appears to induce growth in height and diameter as a function of local environment conditions. Competition for nutrients appears to reduce allocation to fine roots and increase allocation to stem wood.

The effects of silvicultural regimes on leaf area and biomass distribution were analyzed in 16-year old Pinus radiata trees growing in the semiarid zone of Chile. Three stands with different silvopastoral management were compared with a conventionally managed stand. Data were obtained through destructive sampling of 36 trees and analyzed by MANOVA and regression models of ANCOVA. Results show that the management regime affects the leaf area. Specific leaf area was affected by both silvicultural regime and crown position. Total biomass per tree under the silvopastoral regime was 2.1 to 2.5 times larger than in the conventional forestry regime, However, aboveground biomass partitioning was neither affected by the silvicultural regime nor by the schemes of silvopastoral management. The most important allometric change was in fine root biomass, which was greater under the conventional forestry regime than in the silvopastoral one. Fine root biomass increases with a regular distribution of the plants in the field, and decreases with the clumping of trees. Similarly, the fine root biomass decreases with fertilization. Both plantation design and fertilization regimes explain the changes in the fine root biomass to components of the crown. However, crown structure influences the magnitude of these changes.