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The responses of radial and height growth, plant architecture, and the probability of mortality of saplings to varying light levels were quantified for six tree species in temperate conifer forests of the Bhutan Himalayas. Increases in growth with increasing light were comparable with those of high latitude tree species but lower than those of tropical tree species and temperate species in North America. The shade-tolerant species Tsuga dumosa (D. Don.) Eichler showed the strongest increase in radial growth at low light and reached asymptotic growth early. It had the deepest crowns in low light and a low decrease of leader growth with decreasing light. It represents a continuous growth type, which invests in height rather than lateral growth under low light conditions. Betula utilis D. Don. showed greater increases in radial growth and a higher mortality at low light than the more shade-tolerant Abies densa Griff., in keeping with the trade-off between survivorship and growth at low light. Picea spinulosa Griff, Larix griffithiana Carriére, and Pinus wallichiana A.B. Jackson showed small increases in growth at low light levels. The latter two species showed no capacity to adapt their morphology in response to changing light levels, which resulted in higher probabilities of mortality at lower light levels. Differences in the probability of mortality at different light levels were more pronounced than differences in the light-growth response, underlining the importance of survivorship at low light for successional dynamics.Résumé : Les effets de différents niveaux de lumière sur la croissance radiale et la croissance en hauteur, sur l'architecture des arbres et sur les chances de survie des jeunes tiges ont été quantifiés chez six espèces d'arbres dans les forêts tempérées de conifères de la zone himalayenne du Bhoutan. Les augmentations de croissance dues à un niveau de lumière plus élevé étaient comparables à celles qu'on observe chez les espèces d'arbres des latitudes élevées mais infé-rieures à celles des espèces tropicales ou tempérées d'Amérique du Nord. L'espèce tolérante Tsuga dumosa (D. Don.) Eichler a connu la plus forte augmentation de croissance radiale sous une faible intensité lumineuse et a rapidement atteint une croissance asymptotique. Cette espèce avait la cime la plus profonde sous faible intensité lumineuse et subissait une légère diminution de croissance apicale avec la réduction du niveau de lumière. Cette essence est typique du type à croissance continue qui investit dans la croissance en hauteur plutôt que latérale sous faible intensité lumineuse. Betula utilis D. Don. a connu une plus forte augmentation de croissance radiale et de mortalité sous faible intensité lumineuse qu'Abies densa Griff., une espèce plus tolérante, conformément au compromis entre survie et croissance sous faible intensité lumineuse. Picea spinulosa Griff., Larix griffithiana Carriére et Pinus wallichiana A.B. Jackson ont connu de faibles augmentations de croissance sous faible intensité lumineuse. Les deux dernières e...

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Bamboo plantations in two locations in eastern Thailand differed in their biomass yield by an order of magnitude as a result of site productivity and plantation management. The biomass yield of Bambusa beecheyana and Dendrocalamus membranaceus was comparable, but the moisture content of culms of B. beecheyana was considerably higher as compared to D. membranaceus. With D. membranaceus, internodes had higher moisture content, as compared to nodes. The moisture content decreased with increasing height along culms with both species, but this gradient was stronger with D. membranaceus. The moisture content of culms of B. beecheyana declined with increasing culm age, indicating that older culms are more suitable for energetic utilization. While general feedstock characteristics of the two species were comparable, the calorific content of D. membranaceus was significantly higher than of B. beecheyana. Primarily the upper sections and nodes of older culms of both species are attractive options as bioenergy feedstock, but plantations established on marginal sites without proper plantation management will result in very low yields.

Farmers’ climate perceptions are responsible for shaping their adaptive responses and are thus essential to consider for the design of strategies to reduce vulnerability and increase resilience. In this study, we collected social data in four communities in the central Ethiopian Highlands on farmers’ climate perceptions and adaptations using group discussions and PRA tools. We related these to climate data spanning 30 years (1981 to 2010), consisting of daily minimum temperature, maximum temperature and precipitation, modelled for the four communities using global databases and regional meteorological data. We found that farmers’ climate perceptions showed considerable spatial and gender differences. Perceptions matched well with records describing climate variability, particularly in terms of the shortening and the increased variability of the rainy season, as well as the occurrence of extreme drought in recent years. Climate change, described by long-term average increases in temperature and decreases in precipitation, was perceived, but with subordinate priority. Perceived climate impacts included reduced crop yield, increased occurrence of pests and diseases and increased crop damage by extreme events and poverty. Adaptations were mainly land based and included agronomic measures, land management and ecosystem restoration. Furthermore, important gender differences in adaptation could be traced back to typical gender roles. Results highlight the risk of broadcast adaptation programs, such as the government-propagated combination of mineral fertilizers and early maturing crop varieties. Most importantly, they point to the need to consider climate variability, site- and gender-specific perceptions and priorities.

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Although it is obvious that research regarding Sustainable Forest Management (SFM) is context specific and developed over time, not many research papers yet intended to investigate these changes. As a matter of fact, the number of scientific publications addressing SFM is relatively high. Hence, such a wide field cannot be sufficiently covered by traditional literature review approaches. With this paper, we aim at identifying the most convergent narratives within the SFMresearch landscape by applying a text mining methodology to recent scientific literature. By doing so, we generated results that indicate that there may have been three phases in the evolution of SFMresearch: the early phase covers in particular issues regarding land use in tropical and developing countries. Furthermore, papers in this phase tend to focus on general concepts or policy issues. In contrast, the second phase is characterized by a larger share of publications in forestry focused journals. This process is seemingly connected with issues like forest management, certification, forest stand management and the development of sustainability indicators. A third phase can be observed by the relative downturn of publications in forest-focused journals between 2005 and 2010. A new focus in this period is climate change.

We investigated whether species richness, diversity and density of understory herbaceous plants differed along logging (gap) and grazing (primarily by cattle) disturbance gradients, and sought to identify drivers of richness, diversity and density of understory vegetation of logged sites. A factorial experiment was conducted in the mixed conifer forest of Gidakom in Western Bhutan. Levels of the logging treatment included small (0.15 -0.24 ha), medium (0.25 -0.35 ha) and large (0.36 -1.31 ha) gaps. The grazing treatment included grazed (primarily by cattle) and ungrazed (where herbivores were excluded by a fence) plots nested within each gap. Data were collected from 12 gaps (4 replicates at each level of logging) using the point intercept method. Shannon Weaver Diversity and Margalef's indices were used to estimate species diversity and describe species richness, respectively. Soil samples were analyzed for pH and nutrients. The interaction effect of logging and grazing was significant (p≤0.001) only on species diversity. Relative to ungrazed areas, species diversity was significantly higher (0.01≤p≤0.05) in medium grazed gaps. Under grazed conditions, soil P was negatively correlated with gap size and species diversity. While species diversity was positively correlated (0.01≤p≤0.05) with soil N in grazed plots species richness was positively correlated (0.001≤p≤0.01) with soil N in ungrazed plots. Relative density of Yushania microphylla and Carex nubigena were higher under ungrazed conditions. Our study suggests that the combined effect of cattle grazing and logging results in higher species diversity of understory vegetation in medium and grazed gaps in mixed conifer forests of Bhutan,whereas increase or decrease in relative density of major species is determined primarily by the independent effects of grazing and logging. From management perspective, forest managers must refrain from creating large gaps to avoid loss of nutrients (mainly P and N), which may eventually affect tree regeneration. Managers intending to maintain understory vegetation diversity must consider the combined effects of grazing and logging, ensuring low to moderate grazing pressure.