Local knowledge of the impacts of eucalyptus expansion on water security in the Ethiopian highlands

Lack of long-term hydrological monitoring makes it difficult to determine impacts of changing land use on the water dynamics for many catchments in Africa. Here we use local ecological knowledge (LEK) to explore the impacts of rapid expansion of eucalyptus agroforestry on water security in the Ethiopian highlands. Local knowledge about the impacts of changes in tree cover was collected from farmers (n = 30), extension staff (n = 2) and timber merchants (n = 2) in five kebeles within the Jeldu woreda. Jeldu has undergone significant land use change over the last forty years. The area was heavily deforested 20 years ago and farmers associate this time with a major change in the water dynamics. Recently the development of a new road to Goja, the main town, opened up the area as a source of timber for Addis Ababa. This has resulted in a substantial expansion of eucalyptus plots adjacent to roads on the upper plateau and in riparian areas where growth is accelerated. Poorer farmers have been displaced on to the sloping land (which used to be woodland) where there is now evidence of rapid soil degradation. The key findings were that farmers identified significant trade-offs at the plot scale between eucalyptus and adjacent crop fields. They also identified indicators suggesting the sudden increase in eucalyptus cover had accelerated declines in water availability at landscape scales. The study showed the value of using LEK for exploring immediate landscape scale dynamics in the absence of hydrological monitoring. Whilst there is a degree of uncertainty surrounding the impacts of eucalyptus, this research demonstrated local awareness associated of problems associated with unregulated expansion of eucalyptus woodlots on the water regulating capacity at immediate landscape scales in the Ethiopian highlands

Towards Productive Landscapes: Trade-offs in Tree-cover and Income across a Matrix of Smallholder Agricultural Land-use Systems

AbstractOne of the main causes of tropical forest loss is conversion to agriculture, which is constantly increasing as a dominant land cover in the tropics. The loss of forests greatly affects biodiversity and ecosystem services. This paper assesses the economic return from increasing tree cover in agricultural landscapes in two tropical locations, West Java, Indonesia and eastern Bangladesh. Agroforestry systems are compared with subsistence seasonal food-crop-based agricultural systems. Data were collected through rapid rural appraisal, field observation, focus groups and semi-structured interviews of farm households. The inclusion of agroforestry tree crops in seasonal agriculture improved the systems’ overall economic performance (net present value), even when it reduced understorey crop production. However, seasonal agriculture has higher income per unit of land area used for crop cultivation compared with the tree establishment and development phase of agroforestry farms. Thus, there is a trade-off between short-term loss of agricultural income and longer-term economic gain from planting trees in farmland. For resource-poor farmers to implement this change, institutional support is needed to improve their knowledge and skills with this unfamiliar form of land management, sufficient capital for the initial investment, and an increase in the security of land tenure

Bioengineered tooth emulation systems for regenerative and pharmacological purposes

Genetic conditions, traumatic injuries, carious lesions and periodontal diseases are all responsible for dental pathologies. The current clinical approaches are based on the substitution of damaged dental tissues with inert materials, which, however, do not ensure full physiological recovery of the teeth. Different populations of dental mesenchymal stem cells have been isolated from dental tissues and several attempts have already been made at using these stem cells for the regeneration of human dental tissues. Despite encouraging progresses, dental regenerative therapies are very far from any clinical applications. This is tightly connected with the absence of proper platforms that would model and faithfully mimic human dental tissues in their complexity. Therefore, in the last decades, many efforts have been dedicated for the development of innovative systems capable of emulating human tooth physiology in vitro. This review focuses on the use of in vitro culture systems, such as bioreactors and "organ-on-a-chip" microfluidic devices, for the modelling of human dental tissues and their potential use for dental regeneration and drug testing

Agroforestry - The Most Resilient Farming System for the Hilly Northwest of Vietnam

Over 94% of the land of northwestern Vietnam is classified as sloping. Population growth has exerted pressure on local natural resources, with agricultural expansion on steep slopes resulting in forest degradation, landscape fragmentation and severe environmental consequences. Efforts to restore forest ecosystems have been made by the government, however, as the livelihoods of 80% of the population depend on agriculture, the reconversion of land to forest has proven to be an inappropriate solution. Agroforestry offers a potentially sustainable land-use solution, which could re-establish forests, restore ecosystem services, and stabilize local livelihoods. In this paper, we assess the potential of agroforestry development in the region based on the results of two interrelated surveys conducted in 21 representative villages in six districts of three northwestern provinces: 1) a farming system diagnosis implemented in 17 representative villages; and 2) an agroforestry adoption survey with 210 households practising agroforestry in 14 villages. The analysis was strengthened by four years’ experience in implementing an extensive agroforestry project in the region. The studies focussed on assessing key benefits and constraints of existing farming systems, including agroforestry practices, adopted by farmers and identifying the potential for agroforestry development in the region. The results showed that the dominant farming system in the north-western provinces was monoculture of staple crops on slopes, which provided relatively low economic returns. Soil erosion, land degradation, and water shortages resultant from intensive farming practices were the most significant environmental issues in the area. Tree-based farming systems were rare and mostly a result of spontaneous adoption by farmers. Given the mountainous landscape and the need for soil stabilization, agroforestry was seen by farmers as a viable approach. Improving the existing and adopting new, integrated agroforestry systems were identified as viable ways toward sustainable livelihoods in Northwestern Vietnam