Optimal rotations with declining discount rate: incorporating thinning revenues and crop formation costs in a cross-European comparison

Schedules of declining discount rates have been advocated, and adopted by several European governments. They undermine classical solutions to forest economics problems, especially optimal rotation. Adapting classical first-order conditions created problems of local optimisation. A global search algorithm allowed inclusion of initial costs and thinning revenues. It produced results according with expectations – lengthening rotations as time progressed – and results paralleling those for constant discount rates – shorter rotations for high productivity and unthinned crops, and with zero crop formation costs. Apparent anomalies in the pattern of rotations are the due result of opportunity costs from later rotations, which increase as discount rate declines. Sometimes the solution oscillates, usually owing to steps in the discount schedule or irregular profile of felling revenues. Inspection allows the most profitable result to be identified.acceptedVersio

The complexity of the conservation-development nexus in Central African national parks and the perceptions of local populations

peer reviewedConservation programmes of recent decades aimed to adopt an approach that addresses biodiversity conservation goals through socio-economic tools and to better integrate the human dimension into biodiversity conservation. Yet, to analyse this complex conservation-development nexus, studying conservation perceptions of local populations are crucial to understand the dynamics and establish sound conservation-development management policies. Therefore, we aim to identify the key determinants of conservation perceptions in the Central African context in order to implement successful local and regional conservation strategies. Conservation perceptions of two national parks’ adjacent populations were examined through household surveys, adapted from the Poverty- Environment Network (PEN), in Rwanda and Republic of Congo. Outcomes were statistically analysed to identify the most important factors affecting perceptions about conservation measures. Using a nonlinear canonical correlation analysis, we found that economic factors (e.g. salary, savings, cattle size) and education positively affect conservation perceptions while ecosystem-dependent factors such as hunting and gathering other nontimber forest products have negative effects. Though, we identified a significant difference between two sites, whereby, conservation perceptions are negatively affected by bushmeat factors in Republic of Congo, and NTFP in Rwanda. In addition, our study showed that resource use and rights play a major role in communities’ perceptions and that revenue-sharing projects have a key impact on the perceptions. To ensure sound conservation and development measures, revenue-sharing schemes focusing on material benefits and alternative livelihoods may provide the best approach if participation of communities in the decision-making process is ensured. In this optic, improving education levels will raise awareness and positive perceptions of conservation measures. Development measures should target poor households as they appear to be more conservation-adverse. We conclude that in depth research on local demands for ecosystem products, relationships among stakeholders and community decision power are crucial factors to understand the complexity of the conservation-development nexus

Simulating growth-based harvest adaptive to future climate change

Forests are the main source of biomass production from solar energy and take up around 2.4 +/- 0.4 PgC per year globally. Future changes in climate may affect forest growth and productivity. Currently, state-of-the-art Earth system models use prescribed wood harvest rates in future climate projections. These rates are defined by integrated assessment models (IAMs), only accounting for regional wood demand and largely ignoring the supply side from forests. Therefore, we assess how global growth and harvest potentials of forests change when they are allowed to respond to changes in environmental conditions. For this, we simulate wood harvest rates oriented towards the actual rate of forest growth. Applying this growth-based harvest rule (GB) in JSBACH, the land component of the Max Planck Institute's Earth system model, forced by several future climate scenarios, we realized a growth potential 2 to 4 times (3-9 PgC yr(-1)) the harvest rates prescribed by IAMs (1-3 PgC yr(-1)). Limiting GB to managed forest areas (MF), we simulated a harvest potential of 3-7 PgC yr(-1), 2 to 3 times higher than IAMs. This highlights the need to account for the dependence of forest growth on climate. To account for the long-term effects of wood harvest as integrated in IAMs, we added a life cycle analysis, showing that the higher supply with MF as an adaptive forest harvesting rule may improve the net mitigation effects of forest harvest during the 21st century by sequestering carbon in anthropogenic wood products

Методические подходы к определению рационального состава минеральных удобрений

Various methods and approaches to determination of the rational composition of mineral fertilizers are considered. The necessity of use of the ecological component for calculation the optimal set of mineral fertlizers is being grounded. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/1314

Forest carbon allocation modelling under climate change

Peer reviewe

Forest carbon allocation modelling under climate change

Carbon allocation plays a key role in ecosystem dynamics and plant adaptation to changing environmental conditions. Hence, proper description of this process in dynamic vegetation models is crucial for the simulations of the impact of climate change on carbon cycling in forests. Here we review how carbon allocation modelling is implemented in 31 dynamic vegetation models to identify the main gaps compared to our theoretical and empirical understanding of carbon allocation. We found that a hybrid approach based on combining several principles and/or types of carbon allocation modelling prevailed in examined models. The analysis revealed that although the number of carbon allocation studies over the last 10 years has substantially increased, some background processes are still insufficiently understood, and some issues in models are frequently oversimplified or even omitted. Hence, current challenges for carbon allocation modelling in forest ecosystems are (i) to overcome remaining limits in process understanding, particularly regarding the impact of disturbances on carbon allocation, accumulation and utilisation of non-structural carbohydrates, and carbon use by symbionts, and (ii) to implement existing knowledge to mechanistic description of carbon allocation in models that would integrate the impact of environmental conditions, disturbances, and seasonal variation in carbon allocation, or (iii) to improve more simplistic models by accounting for the impact of crucial factors affecting carbon allocation in particular environment

Forest carbon allocation modelling under climate change

Carbon allocation plays a key role in ecosystem dynamics and plant adaptation to changing environmental conditions. Hence, proper description of this process in vegetation models is crucial for the simulations of the impact of climate change on carbon cycling in forests. Here we review how carbon allocation modelling is currently implemented in 31 contrasting models to identify the main gaps compared with our theoretical and empirical understanding of carbon allocation. A hybrid approach based on combining several principles and/or types of carbon allocation modelling prevailed in the examined models, while physiologically more sophisticated approaches were used less often than empirical ones. The analysis revealed that, although the number of carbon allocation studies over the past 10 years has substantially increased, some background processes are still insufficiently understood and some issues in models are frequently poorly represented, oversimplified or even omitted. Hence, current challenges for carbon allocation modelling in forest ecosystems are (i) to overcome remaining limits in process understanding, particularly regarding the impact of disturbances on carbon allocation, accumulation and utilization of nonstructural carbohydrates, and carbon use by symbionts, and (ii) to implement existing knowledge of carbon allocation into defence, regeneration and improved resource uptake in order to better account for changing environmental conditions. © The Author(s) 2019. Published by Oxford University Press