Local spatial structure of forest biomass and its consequences for remote sensing of carbon stocks

Advances in forest carbon mapping have the potential to greatly reduce uncertainties in the global carbon budget and to facilitate effective emissions mitigation strategies such as REDD+. Though broad scale mapping is based primarily on remote sensing data, the accuracy of resulting forest carbon stock estimates depends critically on the quality of field measurements and calibration procedures. The mismatch in spatial scales between field inventory plots and larger pixels of current and planned remote sensing products for forest biomass mapping is of particular concern, as it has the potential to introduce errors, especially if forest biomass shows strong local spatial variation. Here, we used 30 large (8–50 ha) globally distributed permanent forest plots to quantify the spatial variability in aboveground biomass (AGB) at spatial grains ranging from 5 to 250m (0.025–6.25 ha), and we evaluate the implications of this variability for calibrating remote sensing products using simulated remote sensing footprints. We found that the spatial sampling error in AGB is large for standard plot sizes, averaging 46.3% for 0.1 ha subplots and 16.6% for 1 ha subplots. Topographically heterogeneous sites showed positive spatial autocorrelation in AGB at scales of 100m and above; at smaller scales, most study sites showed negative or nonexistent spatial autocorrelation in AGB. We further show that when field calibration plots are smaller than the remote sensing pixels, the high local spatial variability in AGB leads to a substantial “dilution” bias in calibration parameters, a bias that cannot be removed with current statistical methods. Overall, our results suggest that topography should be explicitly accounted for in future sampling strategies and that much care must be taken in designing calibration schemes if remote sensing of forest carbon is to achieve its promise

Individuals who do and do not perceive difficulties adhering to a diet for diabetes mellitus, their quality of life and glycaemic control

Opinion regarding the successful management of insulin dependent diabetes mellitus (IDDM) has identified nutrition as a key player. Whilst important, diet has also been highlighted as one of the most difficult aspects of the regimen, by both individuals with IDDM and health workers. Current dietetic recommendations for the nutritional management of individuals with IDDM include, the normalisation of plasma glucose and the promotion of patient well being. This study aimed to determine if any significant difference in quality of life (QOL) and glycaemic control existed between groups of individuals with IDDM, who perceive their diet difficult to adhere to and those who perceive adherence easy

Crescimento e produtividade de inhame e de milho doce em cultivo associado Growth and productivity of taro and sweet corn under intercropping conditions

Objetivando avaliar a viabilidade agronômica e econômica da associação inhame e milho doce, foi desenvolvido um trabalho em área da horta de pesquisas da Universidade Federal de Viçosa, em sistema de consórcio (associação aditiva), utilizando-se inhame (Colocasia esculenta) 'Chinês' como cultura principal e milho doce (Zea mays) 'Doce Cristal' como cultura contrastante. O inhame foi plantado em sulcos de 12 cm de profundidade, no espaçamento de 100 x 30 cm, e o milho doce em covas de 3 cm de profundidade, na fileira de plantio, entre as plantas de inhame, 40 dias após plantio do inhame. O delineamento experimental foi de blocos ao acaso, com quatro repetições, no esquema fatorial (3 x 2) + 2 (três arranjos de plantas: uma planta de milho a cada 30 cm; duas plantas de milho a cada 60 cm e três plantas de milho a cada 90 cm x dois manejos das plantas de milho: sem e com corte e retirada da parte aérea das plantas de milho no momento da colheita das espigas verdes + dois controles: monoculturas de inhame e de milho doce). Foram avaliadas características de crescimento e de produção das culturas, além dos índices de eficiência dos consórcios. As duas espécies são adequadas para plantio em sistema de consórcio. O arranjo com uma planta de milho a cada 30 cm propiciou maiores produtividades e índices de eficiência dos consórcios. Com exceção do arranjo com três plantas de milho/cova a cada 90 cm com corte da parte aérea das plantas de milho na colheita das espigas, no qual ocorreram menores índices de eficiência dos consórcios e rendimento financeiro total inferior ao da monocultura do inhame, as demais associações estudadas demonstraram-se viáveis agronômica e economicamente.<br>An experiment was conducted to evaluate some crop production characteristics and economic viability of intercropping systems using taro (Colocasia esculenta) 'Chinês', as major crop, and sweet corn (Zea mays) 'Doce Cristal' as minor crop. Taro corms were planted in 12-cm-deep furrows in a 100 x 30 cm spacing. Sweet corn seeds were sowed in the row between the taro plants 40 days after the main crop planting. Corn plants were distributed in three arrays, as follows: one corn plant 30 cm apart; two corn plants 60 cm apart, and three corn plants 90 cm apart; and two growing systems (with and without removing the corn shoot when the ears were harvested at 110 days after sowing - soft kernel stage), comprising six treatments of intergrown and two control treatments (i.e., single crops). The experiments were organized in four random blocks, in a factorial array design (3 x 2) + 2 (three distribution of plants: one corn plant 30 cm apart; two corn plants 60 cm apart, and three corn plants 90 cm apart by two systems of corn growth: with and without removal of shoot when the ears were harvested + two control: single crop of either taro or sweet corn). Data for plant growth, production and the efficiency for the different planting systems arrays were collected. Both crops were suitable for intergrowing systems. Higher values for crop production and intergrowing efficiency index were obtained in treatment with one corn plant 30 cm apart. Lower intergrowing efficiency index and economical return were observed in the treatment where each three corn plants were 90 cm apart and shoots were removed just after the harvest at the soft kernel stage. The others intercrop systems were both agronomically and economically viable