Deforestation and drought are among the greatest environmental pressures on the Amazon rainforest, possibly destabilizing the forest-climate system. Deforestation in the Amazon reduces rainfall ...regionally, while this deforestation itself has been reported to be facilitated by droughts. Here we quantify the interactions between drought and deforestation spatially across the Amazon during the early 21st century. First, we relate observed fluctuations in deforestation rates to dry-season intensity; second, we determine the effect of conversion of forest to cropland on evapotranspiration; and third, we simulate the subsequent downwind reductions in rainfall due to decreased atmospheric water input. We find large variability in the response of deforestation to dry-season intensity, with a significant but small average increase in deforestation rates with a more intense dry season: with every mm of water deficit, deforestation tends to increase by 0.13% per year. Deforestation, in turn, has caused an estimated 4% of the recent observed drying, with the south-western part of the Amazon being most strongly affected. Combining both effects, we quantify a reinforcing drought-deforestation feedback that is currently small, but becomes gradually stronger with cumulative deforestation. Our results suggest that global climate change, not deforestation, is the main driver of recent drying in the Amazon. However, a feedback between drought and deforestation implies that increases in either of them will impede efforts to curb both.
Abstract
Market and public policies govern deforestation trends and patterns globally. Here I show that in the Brazilian Amazon, the largest tropical forest in the world, the size of deforestation ...polygons - the individual portions of cleared forest patches - has significantly increased in response to the current environmental governance. The average size of deforestation polygons in the current government is 61% greater than in the 10 previous years when environmental policies and programs were maintained. As a result, very large polygons (> 100 ha) are now dominating deforestation, suggesting a remarkable change in deforestation patterns and a new wave of destruction of the Amazon forest. To control increasing deforestation trends and changing patterns, command and control policies need to be strengthened along with interventions in the supply chain of Amazon commodities and sustainable development incentives, ensuring a transition to an environmentally sustainable economy.
This article investigates what predicts forest-clearing behaviour in Nigeria. Data was collected using a structured questionnaire among 320 randomly selected crop farmers in Afijio, Oyo state, in ...southwestern Nigeria. Stepwise, multiple linear regression was used to identify the predictors of forest-clearing behaviour. Six variables, derived from a health belief model, determined the prediction of forest-clearing. Results indicate that "perceived barriers' was the best predictor. "Cues to action", "perceived benefit" and "perceived severity" were also good predictors of forest-clearing behaviour. The four constructs correlated with behaviour and explained 20.2% of the variance. Robust perception of barriers to conserving forests and perceived benefit derivable from such conservation aggravates forest degradation. In contrast, the intensity of cues that stimulate forest conservation and the severity of peoples' perception regarding the severity of forest clearing, alleviates forest-clearing. Thus, pursuing forest conservation while invoking these variables is promising for reducing forest-clearing in Nigeria.
This study primarily aims to develop a spatial model for predicting the occurrences of deforestation in Sumatra Island, Indonesia. This study was conducted based on spatial logistic regression ...approach that has been widely acknowledged for its flexibility and ability to accept a mixture of both categorical and numerical variables. Result of this study shows that a combination between logistic regression-based modelling and Geographical Information System (GIS) is indeed suitable for determining the probability of deforestation occurrences in Sumatra Island. Analysis conducted in this study has also revealed that physiographic variables, soil type variables, as well as human activity variables have high significant correlation with deforestation. These findings are useful to assist policy makers in Indonesia to understand the process of deforestation and to take it into consideration while formulating land use-related decisions.
The deforestation of Easter Island Rull, Valentí
Biological reviews of the Cambridge Philosophical Society,
February 2020, 2020-Feb, 2020-02-00, 20200201, Letnik:
95, Številka:
1
Journal Article
Recenzirano
Odprti dostop
ABSTRACT
Easter Island deforestation has traditionally been viewed as an abrupt island‐wide event caused by the prehistoric Rapanui civilization, which precipitated its own cultural collapse. This ...view emerges from early palaeoecological analyses of lake sediments, which showed a sudden and total replacement of palm pollen by grass pollen shortly after Polynesian settlement (800–1200 CE). However, further palaeoecological research has challenged this view, showing that the apparent abruptness and island‐wide synchronicity of forest removal was an artefact due to the occurrence of a sedimentary gap of several millennia that prevented a detailed record of the replacement of palm‐dominated forests by grass meadows. During the last decade, several continuous (gap‐free) and chronologically coherent sediment cores encompassing the last millennia have been retrieved and analysed, providing a new picture of forest removal on Easter Island. According to these analyses, deforestation was not abrupt but gradual and occurred at different times and rates, depending on the site. Regarding the causes, humans were not the only factors responsible for forest clearing, as climatic droughts as well as climate–human–landscape feedbacks and synergies also played a role. In summary, the deforestation of Easter Island was a complex process that was spatially and temporally heterogeneous and took place under the actions and interactions of both natural and anthropogenic drivers. In addition, archaeological evidence shows that the Rapanui civilization was resilient to deforestation and remained healthy until European contact, which contradicts the occurrence of a cultural collapse. Further research should aim to obtain new continuous cores and make use of recently developed biomarker analyses to advance towards a holistic view of the patterns, causes and consequences of Easter Island deforestation.
In this article, the Ryningsnäs site in Sweden is investigated using large eddy simulation with three different clearing setups: a homogeneous forest, that is, no clearing, the current clearing, that ...is, the existing clearing at the location, and an extended clearing. Neutral stratification is simulated, and the wind turbines are modelled by a two‐way‐coupled actuator line model. From the simulations, the electrical generator power was found to be the highest for the current clearing. But the fatigue loads were both higher and lower than the homogeneous forest depending on which part of the wind turbine that was investigated. The extended clearing nearly always had the lowest fatigue loads but unfortunately also the lowest electrical generator power. Further optimization of the clearings and the wind turbine locations in relation to them is needed to find the sweet spot where the fatigue loads are lower and the electrical generator power is higher.
An unprecedented increase in oil palm developments may be underway in Papua New Guinea (PNG) through controversial “special agricultural and business leases” (SABLs) covering over two million ...hectares. Oil palm development can create societal benefits, but doubt has been raised about whether the SABL developers intend establishing plantations. Here, we examine the development objectives of these proposals through an assessment of their land suitability, developer experience and capacity, and sociolegal constraints. Our review reveals 36 oil palm proposals with plantings planned for 948,000 ha, a sevenfold increase over the existing planted area in PNG. Based on our criteria, however, we estimate that only five plantations covering 181,700 ha might eventuate within the foreseeable future. We conclude that most of the developers are clearing forest with no intention of cultivating oil palm, and that a large‐scale land grab is therefore occurring in PNG under the guise of oil palm development.
Off-farm employment in rural households has been cited in the literature as a potentially ideal alternative to reduce forest clearing and pressure on natural resources, since it provides income while ...at the same time taking household labor away from the farm. Nonetheless, empirical research on the relationship between off-farm work and natural resource use is still scarce. This paper examines the impact of off-farm work on forest clearing, logging, hunting, and fishing among both migrant colonists and indigenous populations in the Ecuadorian Amazon. In contrast to prior research, we use an instrumental variable approach to control for the potential endogeneity of off-farm work with respect to natural resource use. The results indicate that the higher the number of days worked off-farm at the household level, the lower the forest clearing. On the other hand, the number of days worked off-farm has no effect on logging, hunting, and fishing. The implications of this for sustainable development and conservation are explored in the conclusion section.
The effort to automate is present across all industries. It has an economic purpose but potential impacts go far beyond economics. Research has been carried out and a lot of investment has been made ...in automation in a variety of industries, as well as in agriculture and forestry, which resulted in efficient solutions for diverse applications. In fact, more solutions have emerged in the field of agriculture than in any other. This can be explained in economic terms, but also in light of the complex navigation required because of unstructured environments such as forests. This paper provides a comprehensive review of existing mobile platforms and presents a comparative study for an application in forest clearing. We evaluate the size, automation levels, traction, energy source, locomotion systems, sensors/actuators availability and tools that such an application must have to succeed in its function. Hence, it will be possible to evaluate the feasibility of retrofitting an existing platform into an electric unmanned ground vehicle for forest clearing or if it is easier to start development from scratch. The evaluation results reveal that an electric unmanned ground vehicle for forest clearing is currently unavailable in the market and that a new platform is needed. The performance requirements for such a platform are identified and proposed in the paper.
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