Certification of açaí agroforestry increases the conservation potential of the Amazonian tree flora

The harvesting of açaí berries (palm fruits from the genus Euterpe) in Amazonia has increased over the last 20 years due to a high local and global market demand and triggered by their widely acclaimed health benefits as a ‘superfood’. Although such increase represents a financial boom for local communities, unregulated extraction in Amazonia risks negative environmental effects including biodiversity loss through açai intensification and deforestation. Alternatively, the introduction of certified sustainable agroforestry production programs of açaí has been strategically applied to reduce the exploitation of Amazonian forests. Local açaí producers are required to follow principles of defined sustainable management practices, environmental guidelines, and social behaviors, paying specific attention to fair trade and human rights. In this study we investigate whether sustainable agroforestry and certification effectively promotes biodiversity conservation in Amazonia. To address this question, we conducted a forestry inventory in two hectares of long-term certified açai harvesting areas to gain further knowledge on the plant diversity and forest structure in açaí managed forests and to understand the contribution of certification towards sustainable forest management. On average, we found that certified managed forests harbor 50% more tree species than non-certified açaí groves. Trees in certified areas also have significantly higher mean basal area, meaning larger and hence older individuals are more likely to be protected. Certified harvesting sites also harbor dense populations of threatened species as classified by the International Union for Conservation of Nature (e.g. Virola surinamensis, classified as ‘endangered’). Besides increasing the knowledge of plant diversity in açaí managed areas, we present baseline information for monitoring the impact of harvesting activities in natural ecosystems in Amazonia.

Regeneration Status of Sal (Shorea robusta Gaertn.) in Community Managed Forests, Tanahun District, Nepal

The present research aims to know the regeneration status of community managed Shorea robusta (Sal) forests; managed for 6-21 years in Tanahun district, a part of Gandaki Province, Nepal. These forests were categorized into two groups according to management duration (more than 10 years and equal or less than 10 yrs). The regeneration status of the forest was estimated by calculating the density of each species in each developmental phase (seedling, sapling and tree). The total tree density of community forest managed for more than 10 years (MCF forest; 1230 plants/ha) was less than the community forest managed for equal or less than 10 years (LCF forest; 1314 plants/ha). The results suggest that the size class distribution of the trees resembling inverse-J shaped indicates the good regenerating capability of both forests. After the handover of forests to the community, Sal density had increased rapidly in both the forests. Community management had a significant positive impact on the regeneration of the forest, and thus, the productivity of the forest. Thus, the study of regeneration of forest trees has important implications for the conservation and management of natural forests.

Bayesian inference of biomass growth characteristics for sugi (C. japonica) and hinoki (C. obtusa) forests in self-thinned and managed stands

Background Forests are an important sink for atmospheric carbon and could release that carbon upon deforestation and degradation. Knowing stand biomass dynamic of evergreen forests has become necessary to improve current biomass production models. The different growth processes of managed forests compared to self-managed forests imply an adaptation of biomass prediction models. Methods In this paper we model through three models the biomass growth of two tree species (Japanese cedar, Japanese cypress) at stand level whether they are managed or not (self-thinning). One of them is named self-thinned model which uses a specific self-thinning parameter α and adapted to self-managed forests and an other model is named thinned model adapted to managed forests. The latter is compared to a Mitscherlich model. The self-thinned model takes into account the light competition between trees relying on easily observable parameters (e.g. stand density). A Bayesian inference was carried out to determine parameters values according to a large database collected. Results In managed forest, Bayesian inference results showed obviously a lack of identifiability of Mitscherlich model parameters and a strong evidence for the thinned model in comparison to Mitscherlich model. In self-thinning forest, the results of Bayesian inference are in accordance with the self-thinning 3/2 rule (α=1.4). Structural dependence between stand density and stand yield in self-thinned model allows to qualifying the expression of biological time as a function of physical time and better qualify growth and mortality rate. Relative mortality rate is 2.5 times more important than relative growth rate after about 40 years old. Stand density and stand yield can be expressed as function of biological time, showing that yield is independent of initial density. Conclusions This paper addressed stand biomass dynamic models of evergreen forests in order to improve biomass growth dynamic assessment at regional scale relying on easily observable parameters. These models can be used to dynamically estimate forest biomass and more generally estimate the carbon balance and could contribute to a better understanding of climate change factors.

Priraščanje navadne smreke (Picea abies (L.) Karst.) in evropskega macesna (Larix decidua Mill.) na nekdanjih novinah v koprivni v Karavankah

Based on previous measurements from 1962 to 2017 on forest research plots located on former slash-and-burn farming areas in the cadastral municipality of Koprivna, the diameter and height increment as well as volume increments of the two main tree species - spruce and larch - were calculated. These set-aside natural research plots have a smaller mean basal area diameter, but the number of trees is higher than in comparable managed forests. Due to the high-density of tree stands over the past thirty years, radial increment of spruce and larch has declined. To determine the influence of environmental factors on radial growth of spruce and larch, a dendrochronological analysis was conducted. According to the dendrochronological analysis of radial increment of trees, the number of years with a negative response has been higher since 1984.

Perceptions of Local Inhabitants towards Land Management Systems Used in the Rainforest Area of Ecuador: An Evaluation Based on Visual Rating of the Main Land Use Types

Land management policy and practice affects a wide segment of stakeholders, including the general population of a given area. This study evaluates the perceptions of local inhabitants towards the land management systems used in the rainforest area of Ecuador—namely, unmanaged (natural) forest, managed forest, croplands, and pasturelands. Data collected as ratings on 12 pictures were used to check the aggregated perceptions by developing the relative frequencies of ratings, in order to see how the perception rating data were associated with the types of land management systems depicted by the pictures, and to see whether the four types of land management could be mathematically represented by a clustering solution. A distinctive result was that the natural forests were the most positively rated, while the managed forests were the least positively rated among the respondents. It seems, however, that human intervention was not the landscape-related factor affecting this perception, since croplands and pasturelands also received high ratings. The ratings generated a clear clustering solution only in the case of forest management, indicating three groups: natural forests, managed forests, and the rest of the land management systems. Based on the results of this study, a combination of the four land use systems would balance the expectations of different stakeholders from the area, while also being consistent to some extent with the current diversity in land management systems. However, a more developed system of information propagation would be beneficial to educate the local population with regards to the benefits and drawbacks of different types of land management systems and their distribution.