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The main objective of the current study reflects and questions the colonial methodologies on research. This is based on the indigenous people’s vision in order to make a small contribution to the fields on intercultural and plurilingual education of Bolivia. In this sense, a bibliographical revision has mainly carried out. This bibliography was based on the research on Taller de Historia Oral Andina, the Programa de Formación en Educación Intercultural Bilingüe para los Países Andinos, Agroecología Universidad Cochabamba, and the Consejos Educativos de Pueblos Originarios. The four experiences are gradually distant from the colonial traditional methodologies that come from the modern sciences. The proposals of those experiences, with more or less emphasis, find the dialogue with millennial indigenous knowledge systems. These experiences are critically framed in the new Sociocommunitary Productive Educative System in Bolivia in the sense that could bring us important approaches in the required construction in order to study models with a communitarian transversal vision in the education systems. The principal contributions of these experiences are oral history, the academic training of the indigenous scholars, the construction of southern epistemic models, and the community management of knowledge., El objetivo de este trabajo es reflexionar y cuestionar las metodologías coloniales de investigación a partir de la visión de los pueblos indígenas y realizar un pequeño aporte al campo de la educación intra-, intercultural y plurilingüe en Bolivia mediante una revisión bibliográfica de las propuestas de investigación de cuatro experiencias: Taller de Historia Oral Andina, Programa de Formación en Educación Intercultural Bilingüe para los Países Andinos, Agroecología Universidad Cochabamba y Consejos Educativos de Pueblos Originarios, las cuales poco a poco se desmarcan de las metodologías coloniales provenientes de la ciencia moderna; entre sus planteamientos se encuentra el diálogo con los milenarios sistemas de conocimientos indígenas. Estas experiencias se visualizan de manera crítica en el marco del nuevo Modelo Educativo Sociocomunitario Productivo en Bolivia, ya que pueden brindar importantes aportaciones a la necesaria construcción de modelos de investigación sociocomunitaria transversales a todo el sistema educativo, como la historia oral, la especialización de indígenas profesionales, la construcción de modelos epistémicos del sur, y la gestión comunitaria de saberes y conocimientos.

Currently, about 70% of the forest land in Europe is covered by stands composed of two or more tree species. The similar situation can be found outside Europe too. While forest management of monocultures is well described multispecies forests still need a better understanding to develop appropriate forest practice. Managing mixed forests can be more complex than managing monocultures because of the need to optimize the provision of multiple benefits according to the societal demands including sustaining biodiversity and ecosystem functioning.

Climate change forecasts are particularly severe for the western Mediterranean Basin, where rising temperatures and decreased precipitation could increase the frequency of drought events. Understanding the specific weather drivers of radial variation in Mediterranean mixed forest stands will allow us to better predict the ecological and production alterations that may result from climate change. Here, we studied species differences in stem daily radial variation cycles and daily radial increment of Mediterranean pine-oak (Pinus pinaster-Quercus pyrenaica) mixed stands over three climatically contrasted years (2012-2014) at two sites with dissimilar drought conditions. Our aim was to uncover differences in the weather drivers of daily radial variation for the two co-existing species. High-resolution point dendrometers were installed in dominant oak and pine trees, so that daily radial variation cycles were analyzed. Linear mixed models were fitted to analyze species-specific response to weather. Air temperature leads to radial stem-size changes in daily variation cycles with different species responses. Precipitation increased daily radial variation and cycle duration in the same way for both species. Daily radial increment and number of cycles with increment phase during spring was mostly higher for pine than oak, and water availability was the most important control factor for the phase mentioned. Differences in species response to weather conditions may offset the usual low production of pure oak coppice Mediterranean stands and highlight the role of mixed forests as a possible adaptation strategy for climate change.

Climate change forecasts are particularly severe for the western Mediterranean Basin, where rising temperatures and decreased precipitation could increase the frequency of drought events. Understanding the specific weather drivers of radial variation in Mediterranean mixed forest stands will allow us to better predict the ecological and production alterations that may result from climate change. Here, we studied species differences in stem daily radial variation cycles and daily radial increment of Mediterranean pine-oak (Pinus pinaster-Quercus pyrenaica) mixed stands over three climatically contrasted years (2012-2014) at two sites with dissimilar drought conditions. Our aim was to uncover differences in the weather drivers of daily radial variation for the two co-existing species. High-resolution point dendrometers were installed in dominant oak and pine trees, so that daily radial variation cycles were analyzed. Linear mixed models were fitted to analyze species-specific response to weather. Air temperature leads to radial stem-size changes in daily variation cycles with different species responses. Precipitation increased daily radial variation and cycle duration in the same way for both species. Daily radial increment and number of cycles with increment phase during spring was mostly higher for pine than oak, and water availability was the most important control factor for the phase mentioned. Differences in species response to weather conditions may offset the usual low production of pure oak coppice Mediterranean stands and highlight the role of mixed forests as a possible adaptation strategy for climate change.

Studying species interactions in mixed forests allows us to assess their potential benefits and adapt current silvicultural tools developed in monospecific stands to multi-specific stands. We analyzed tree interactions in a Pinus halepensis Mill. and Pinus pinea L. mixed plantation using individual tree neighborhood models and competition indices that accounted for symmetric and asymmetric competition, to analyze whether the growth of each species was better explained by symmetric or asymmetric competition. We also split the competition indices into their intra- and interspecific forms, to test for competition effects on growth change based on competitor identity. Finally, we analyzed whether P. halepensis and P. pinea trees had different growth responses to competition. When calculating competition indices, we explored how spatial information and size of competitor trees contributed to the quantification of the process. Competition measurements were optimized to more precisely describe interactions. Results showed that the inclusion of competition indices generated important improvements in growth models. The main mode of competition was symmetric, which could be related to water restrictions typical of the Mediterranean climate. Considering competitor identity did not improve the growth models, while measurement without discriminating competitors by species generated more parsimonious models. P. halepensis and P. pinea trees had similar growth responses to competition, indicating that the two species cope with competition in similar ways. However, P. pinea showed lower average growth than P. halepensis in the period analyzed. Results suggest that preventing the onset of intense interspecific competition processes could help slow down the long-term replacement of P. pinea by P. halepensis and could have benefits for silvicultural management in systems with two species that share ecological niches but are capable of generating different goods and services.

Aim of study Designing adequate silvicultural systems for natural regeneration of a forest species requires sound knowledge of the underlying ecological subprocesses flowering and fruiting, seed dispersal and predation, seed germination, seedling emergence and seedling survival. The main objective of the present work is to carry out a review on the current knowledge about the different subprocesses governing the regeneration process for the main Iberian Pinus species, in order to propose scientifically based management schedules. Area of study The review focuses on the five main native Pinus species within their most representative areas in the Iberian Peninsula Pinus nigra in Cuenca mountains, Pinus sylvestris in Sierra de Guadarrama, Pinus pinaster and Pinus pinea in the Northern Plateau and Pinus halepensis in Catalonia. Material and methods Firstly, currently available information on spatiotemporal dynamics and influential factors is introduced for each subprocess and species. Secondly, current regeneration strategies are characterized and the main bottlenecks are identified. Finally, alternative silvicultural practices proposed on the light of the previous information are presented. Main results Different climate-mediated bottlenecks have been identified to limit natural regeneration of the Iberian pine species, with seed predation and initial seedling survival among the most influential. New approaches focusing on more gradual regeneration fellings, extended rotation periods, prevent big gaps and program fellings on mast years are presented. Research highlights Natural regeneration of the studied species exhibit an intermittent temporal pattern, which should be aggravated under drier scenarios. More flexible management schedules should fulfil these limitations. © 2017 INIA.

Radial increment analyses allow us to determine tree responses to weather and tree competition, thus enabling the development of management strategies for adapting forest stands to forecasted climate change scenarios. In this study, the responses of pine-oak mixed stands (Pinus pinaster Ait.;Quercus pyrenaica Willd.) to thinning treatments were assessed at two sites in central Spain with contrasting drought conditions. Inter- and intra-annual radial increments were recorded every two weeks from dendrometer band measurements, using a Latin square design. Each site consisted of a control (unthinned) and two thinning intensities moderate (25% of pine basal area removed) and heavy (40% of pine basal area removed). Thinning effects were monitored over three years of different weather conditions (2010–2012), with an extreme drought event in 2012. Linear mixed models were fitted to analyze weather and thinning effects on the inter- and intra-annual radial increment rates. Additionally, the sum of two logistic functions was used to estimate cumulative radial increment patterns. Heavy thinning resulted in the greatest annual radial increment for pine, regardless of site and year, even during the 2012 drought, when compared to densely stocked forest stands. The model results indicated that heavy thinning positively affected the intra-annual pattern, increasing inflection point and spring and autumn asymptotes. Thinning also had a slight positive effect on inter- and intra-annual radial increment in oak, although this was not clear during extreme drought in 2012. The radial increment rate was related to weather variables, which reflected light (positive for solar radiation) and water availability dependence (increased with precipitation, but decreased with vapor pressure deficit) for both species. Besides water status, air humidity (positive relation with air temperature and relative humidity) also affected oak. Reducing competition by thinning stimulated radial increment in o

Mixed-species stands have been studied extensively due to their potentially superior productivity, multi-functionality benefits and high ecological value compared to pure stands. The higher structural heterogeneity in mixed stands that can emerge from species interactions could be linked to the relationship between species diversity and ecosystem functions. We tested whether changes in stand structure also occur in mixtures of species with similar traits and whether they explain over-yielding patterns. Based on research with 12 triplets of Scots pine (Pinus sylvestris L.) and Maritime pine (Pinus pinaster Ait.) in the northern Iberian Peninsula (Spain), we provide evidence that species mixing increased structural heterogeneity and may induce over-yielding in mixed-species stands compared to monospecific stands. In this mixture of two light-demanding species, we observed that (i) stand composition influenced the inter-specific crown allometric variation, (ii) structural heterogeneity in mixed stands was caused by both specie-specific traits and species interactions, and (iii) intraspecific and interspecific differences in both crown size plasticity and size-distribution differentiation were associated with the increased relative productivity of mixed stands. We detected that crown complementarity and vertical stratification in the canopy space is a crucial mechanism for enhancing ecosystem productivity in light-demanding species and could be related to light interception and light-use. This work improves our understanding of emerging properties in mixed stands and introduces considerations for properly scaling and tracing mixing effects at individual tree, size distribution and stand levels. © 2017 Elsevier B.V.

Increased interest in mixed forests is due to evidence of them being more resource-use efficient and stable forest systems. However, intrinsic and extrinsic factors moderate interspecific species interactions generating different effects in productivity. Here, we explore a method to detect mixing effects in a specific mixture com_x0002_bination (Pinus sylvestris L. and Pinus pinaster Ait.), comparing the growth of mixed stands with that of mono_x0002_cultures. Combined tree and stand-level analyses also helped determine which mixing effects are most important for forest functioning and how changes at one level influence patterns at another level. Data from the Spanish National Forest Inventory were used to compare growth efficiency in mixed and pure stands; we relied on relative stand density indices to determine species-specific site occupancy. This same concept was used to evaluate competition status and inter/intra-specific competition effects as modifiers of potential growth at the tree-level. We observed that growth efficiency in both species increased with the proportion of the complementary species in the stand. At the tree-level, intraspecific competition was higher than interspe_x0002_cific competition in Scots pine tree growth, showing that it had benefited from the mixture. In contrast, mari_x0002_time pine did not show a competitive response to the interspecific interaction, indicating that tree growth was more strongly influenced by the competition structure (size-symmetric and size-asymmetric) than by the spe_x0002_cies of the competitors. Our results highlight the importance of combining stand-level analysis with that of tree-specific competition relationships when studying mixed-species forests.

Aim of the study: To review and acknowledge the value of carbon sequestration by forest management in the Mediterranean area. Material and methods: We review the main effects of forest management by comparing the effects of silvicultural systems (even-aged vs. uneven-aged stands, coppice systems, agroforestry systems), silvicultural options (thinning, rotation period, species composition), afforestation, harvesting, fire impact or effects of shrub layer on carbon sequestration in the Mediterranean area. Main results: We illustrate as forest management can clearly improve forest carbon sequestration amounts. We conclude that forest management is an effective way to maintain and enhance high carbon sequestration rates in order to cope with climate change and provision of ecosystem services. We also think that although much effort has been put into this topic research, there are still certain gaps that must be dealt with to increase our scientific knowledge and in turn transfer this knowledge to forest practitioners in order to achieve sustainable management aimed at mitigating climate change. Research highlights: It is important to underline the importance of forests in the carbon cycle as this role can be enhanced by forest managers through sustainable forest management. The effects of different management options or disturbances can be critical as regards mitigating climate change. Understanding the effects of forest management is even more important in the Mediterranean area, given that the current high climatic variability together with historical human exploitation and disturbance events make this area more vulnerable to the effects of climate change.

The driest part of the Argentinean pampas is occupied by semiarid woodlands dominates by Prosopis caldenia Burkart (Calden). Calden pods are a highly valuable fodder supplement for livestock but its production is highly variable. Our objective was to analyze and model the temporal pattern in inter-annual variability of Calden pod production. Our key hypothesis is that weather conditions are the main determinant of the pod masting behaviour. Tree size and climatic variables were evaluated as explanatory covariates using a zero-inflated log-normal modelling approach. The proposed final model structure incorporated 25 parameters, including four variance components, two intercepts for both the logistic and the log-normal parts of the model, and nineteen parameters associated with fixed effects. Climate had a strong influence on the flowering-fruiting Calden process and on the inter-annual variability of the final pod production at the tree level. Temperatures during bud breaking, flowering and fruit shedding, together with the precipitation from the final month of fruit shedding and the total amount of the prior vegetative cycle, were the main weather covariates that affect the processes. © 2016 Elsevier Ltd.

African tropical forests are thought to play an important role in global carbon sequestration. However, the increasing rate of deforestation and the impact of changes in land use require a critical and updated look at what is happening. This work emphasizes the role of bulk density as a main driver in carbon (C) and nitrogen (N) stock in four land-use categories natural forest, tree plantations, crop land and degraded soil. The study was conducted in the Central Highlands of Ethiopia, where deforestation and human pressure on native forests are exacerbated and erosion has caused extensive soil loss. The methodological approach consisted of evaluating the confounding effect of bulk density and then estimating C and N stocks based on a fixed-mass method rather than the usual fixed-depth method, in order to compare differences across land use categories. We hypothesized that elevation gradient would play a determining role in C and N concentrations and stocks in native forest, whereas tree species would be the main factor in plantations. C and N concentrations and bulk densities in mineral soil were analyzed as repeated measures in an irregular vertical space ranging from 0-10. cm, 10-30. cm, 30-50. cm and 50-100. cm, using a linear mixed model approach. Single observations from the forest floor were analyzed by a general linear model. Results indicated that soil depth is a more important factor than elevation gradient in native forests, though C and N concentrations and stocks diminished near human settlements. Native forest stored on average 84.4%, 26.4% and 33.7% more carbon and 82.4%, 51.8% and 27.1% more nitrogen than bare soil, crop land and plantations, respectively. Conversion of crop and degraded land to plantations ameliorated soil degradation conditions, but species selection did not affect carbon and nitrogen stocks. © 2015 Elsevier B.V.

The growth and yield of mixed-species stands has become an important topic of research since there are certain advantages of this type of forest as regards functions and services. However, the concepts and methods used to characterize mixed stands need to be understood, as well as harmonized and standardized. In this review we have compiled a set of measures, indices, and methods at stand level to characterize the structure, dynamics, and productivity of mixed stands, and we discuss the pros and cons of their application in growth and yield studies. Parameters for the characterization of mixed stand structure such as stand density, species composition, horizontal (intermingling) and vertical tree distribution pattern, tree size distribution, and age composition are described, detailing the potential as well as the constraints of these parameters for understanding resource capture, use, and efficiency in mixed stands. Furthermore, a set of stand-level parameters was evaluated to characterize the dynamics of mixed stands, e.g. height growth and space partitioning, self- and alien-thinning, and growth partitioning among trees. The deviations and changes in the behaviour of the analysed parameters in comparison with pure stand conditions due to inter-specific interactions are of particular interest. As regards stand productivity, we reviewed site productivity indices, the growth–density relationship in mixed stands as well as methods to compare productivity in mixed versus monospecific stands. Finally, we discuss the main problems associated with the methodology such as up-scaling from tree to stand level as well as the relevance of standardized measures and methods for improving forest growth and yield research in mixed stands. The main challenges are also outlined, especially the need for qualitatively sound data. © 2015, Springer-Verlag Berlin Heidelberg.

Chilimo forest is one of the few remnants of dry afro-montane mixed uneven-aged natural forest located in Central Highlands of Ethiopia. Also it has been during the last century one of the most exploited and disturbed forest in the country. Stand density management diagram (SDMD) is a stand-level model that graphically illustrates the relationships between wood yield, density and mortality throughout all stages of stand development. SDMD is a useful tool for designing, displaying and evaluating alternative density management regimes for both even-aged and uneven-aged forest stands. However, information in this regard and other silvicultural management operations are lacking for most Ethiopian forests in general and Chilimo dry afro-montane forest in particular. The purpose of the study is to develop a SDMD model for the existing mixed natural forest using appropriate species proportion for Juniperus procera and Podocarpus falcatus. Two linear equations were simultaneously fitted to relate quadratic mean diameter with stand density and dominant height and relate it to total stand volume with quadratic mean diameter, stand density and dominant height. Moreover, dominant height and quadratic mean diameter were found to be the best endogenous variables for SDMD for Chilimo forest. The relationship between stand density, dominant height, quadratic mean diameter and stand volume is represented in the SDMD graph. Formulating SDMD using species proportion is better than treating each species independently. This SDMD is the first diagram model developed for mixed forest in Africa, and it can serve sustainable management of Chilimo dry afro-montane forest in particular and other dry afro-montane forests in general. © 2016, Springer-Verlag Berlin Heidelberg.