Linking Remote-Sensing Information to Tropical Forest Structure: The Crucial Role of Modelling

A researcher is shown climbing into the canopy of a primary forest in Southern Cameroon to measure tree height and crown dimensions. Photo: Courtesy of authors.

A researcher is shown climbing into the canopy of a primary forest in Southern Cameroon to measure tree height and crown dimensions. Photo: Courtesy of authors.

Earthzine, posted on April 24th, 2012

Pierre Couteron, Nicolas Barbier, Christophe Proisy, Raphaël Pélissier, and Grégoire Vincent

“Using remote sensing to provide reliable information over extensive areas of dense and heterogeneous tropical forests is a challenging task. Not only is the task challenging, but it also has become closely related to global concerns about reducing greenhouse gas emissions from deforestation and forest degradation, also known as the REDD process. The AMAP laboratory in Montpellier, France, is contributing to this challenge at the interface between signal processing and plant and vegetation modelling which is its central domain of expertise. Models of forest structure are an important tool to fill the scale gap between field observations and remotely sensed information. They help also to understand the complex interactions between signal and forest vegetation. As remotely-sensed data are diversifying, coupling forest structure and radiative transfer models helps to translate signal information into biophysical parameters. Refining such an approach is needed to design replicable methods that address the most challenging aspect of monitoring spatiotemporal variations of stand structure in forest types retaining high aboveground biomass.”

Development of Spatial Database for Sustainable Micro-level Planning of Chandanpur Mouza, Purulia, West Bengal

eTraverse: The Indian Journal of Spatial Science, Vol. II No. 2 — 2011

Abhijit Ghosh, Proshanta Kumar Ghosh, and Debajit Datta

“Micro-level planning in a comprehensive way, acts as one of the key factors in sustainable rural development and natural resource management. For preparation of appropriate micro-level planning strategies, proper and sufficient amount of real time spatial database is needed which can be successfully developed through digital mapping and decision support systems like GIS.

Landuse and Land cover

Landuse and Land cover

“Chandanpur Mouza in the Bhagabandh GP, Barabazar Block of Purulia District, West Bengal has been studied on a pilot basis for the preparation of such spatial databases with the ultimate objective of sustainable development and management of the area.”

Mapping Genetic Diversity of Cherimoya (Annona cherimola Mill.): Application of Spatial Analysis for Conservation and Use of Plant Genetic Resources

PLoS ONE, published 09 Jan 2012

Maarten van Zonneveld, Xavier Scheldeman, Pilar Escribano, María A. Viruel, Patrick Van Damme, Willman Garcia, César Tapia, José Romero, Manuel Sigueñas, and José I. Hormaza

“There is a growing call for inventories that evaluate geographic patterns in diversity of plant genetic resources maintained on farm and in species’ natural populations in order to enhance their use and conservation. Such evaluations are relevant for useful tropical and subtropical tree species, as many of these species are still undomesticated, or in incipient stages of domestication and local populations can offer yet-unknown traits of high value to further domestication. For many outcrossing species, such as most trees, inbreeding depression can be an issue, and genetic diversity is important to sustain local production. Diversity is also crucial for species to adapt to environmental changes.

Allelic richness corrected for sample size by using rarefaction.

Allelic richness corrected for sample size by using rarefaction.

“This paper explores the possibilities of incorporating molecular marker data into Geographic Information Systems (GIS) to allow visualization and better understanding of spatial patterns of genetic diversity as a key input to optimize conservation and use of plant genetic resources, based on a case study of cherimoya (Annona cherimola Mill.), a Neotropical fruit tree species. We present spatial analyses to (1) improve the understanding of spatial distribution of genetic diversity of cherimoya natural stands and cultivated trees in Ecuador, Bolivia and Peru based on microsatellite molecular markers (SSRs); and (2) formulate optimal conservation strategies by revealing priority areas for in situ conservation, and identifying existing diversity gaps in ex situ collections. We found high levels of allelic richness, locally common alleles and expected heterozygosity in cherimoya’s putative centre of origin, southern Ecuador and northern Peru, whereas levels of diversity in southern Peru and especially in Bolivia were significantly lower. The application of GIS on a large microsatellite dataset allows a more detailed prioritization of areas for in situ conservation and targeted collection across the Andean distribution range of cherimoya than previous studies could do, i.e. at province and department level in Ecuador and Peru, respectively.”

Identifying Bus Stop Redundancy: A GIS-based Spatial Optimization Approach

Computers, Environment and Urban SystemsComputers, Environment and Urban Systems, Available Online 25 February 2012

Eric M. Delmelle, Shuping Li, and Alan T. Murray

“Highlights:

  • A Spatial Interaction Coverage (SIC) model is used for transit planning.
  • SIC presents an alternative modeling tool to increase system efficiency while maintaining suitable access coverage.
  • Model parameters (access distance and facility attraction) are calibrated through consultations with local transit planners.
  • Simulated annealing heuristic is developed within a GIS to solve this non-linear problem.

“Transit planners are often faced with a tradeoff between improving accessibility through the addition of stops while simultaneously increasing efficiency so that destinations can be reached in a reasonable amount of time. In this paper, we propose the development of an optimization framework integrated within a Geographical Information System (GIS) for addressing this specific problem. Our proposed modeling framework departs from well-known facility location coverage models by considering both the impact of walking distance from an individual residential location to a stop and the transit facility attractiveness (ease to cross, number of destinations served). Integration within a GIS environment is accomplished using a simulated annealing heuristic. An example on an inbound urban bus route illustrates the utility of the approach for transit planning, using model parameters developed in collaboration with local transit agencies.”

Patterns of Obesogenic Neighborhood Features and Adolescent Weight: A Comparison of Statistical Approaches

American Journal of Preventive MedicineAmerican Journal of Preventive Medicine, May 2012, Vol. 42, No. 5

“Background: Few studies have addressed the potential influence of neighborhood characteristics on adolescent obesity risk, and fındings have been inconsistent.

“Purpose: Identify patterns among neighborhood food, physical activity, street/transportation, and socioeconomic characteristics and examine their associations with adolescent weight status using three statistical approaches.

“Methods: Anthropometric measures were taken on 2682 adolescents (53% female, mean age 14.5 years) from 20 Minneapolis/St. Paul MN schools in 2009–2010. Neighborhood environmental variables were measured using GIS data and by survey. Gender-stratifıed regressions related to BMI z-scores and obesity to (1) separate neighborhood variables; (2) composites formed using factor analysis; and (3) clusters identifıed using spatial latent class analysis in 2012.

“Results: Regressions on separate neighborhood variables found a low percentage of parks/recreation, and low perceived safety were associated with higher BMI z-scores in boys and girls. Factor analysis found fıve factors: away-from-home food and recreation accessibility, community disadvantage, green space, retail/transit density, and supermarket accessibility. The fırst two factors were associated with BMI z-score in girls but not in boys. Spatial latent class analysis identified six clusters with complex combinations of both positive and negative environmental influences. In boys, the cluster with highest obesity (29.8%) included low SES, parks/recreation, and safety; high restaurant and convenience store density; and nearby access to gyms, supermarkets, and many transit stops.

“Conclusions: The mix of neighborhood-level barriers and facilitators of weight-related health behaviors leads to diffıculties disentangling their associations with adolescent obesity; however, statistical approaches including factor and latent class analysis may provide useful means for addressing this complexity.”

Web Presence of Academic Geographers: A Generational Divide?

The Professional GeographerThe Professional Geographer, Accepted 14 April 2012

Matthew W. Wilson and Sarah Starkweather

“The pervasiveness of the Internet in society has brought about changes in academia and shifts in the day-to-day practices of many academics. Here, the web practices of academic geographers are specifically examined through an Internet-based survey, to better understand how these geographers both present themselves through the Internet and perceive the importance of such practices around web presence. Situated within this increasing importance of the Internet as part of professional practice and the neoliberalization of the university, the changes in the teaching and research of academics are overviewed. We then discuss our findings, which indicate a relationship between generation and web practices, and which further reinforce the need for a more central discussion of the importance of web presence within the context of a knowledge economy.”

Economic Vulnerability of Timber Resources to Forest Fires

Journal of Environmental ManagementJournal of Environmental Management, 100 (2012) pp. 16-21

Francisco Rodríguez y Silva, Juan Ramón Molina, Armando González-Cabán, and Miguel Ángel Herrera Machuca

“The temporalespatial planning of activities for a territorial fire management program requires knowing the value of forest ecosystems. In this paper we extend to and apply the economic valuation principle to the concept of economic vulnerability and present a methodology for the economic valuation of the forest production ecosystems. The forest vulnerability is analyzed from criteria intrinsically associated to the forest characterization, and to the potential behavior of surface fires.

Timber resources vulnerability for the Córdoba Province.

Timber resources vulnerability for the Córdoba Province.

“Integrating a mapping process of fire potential and analytical valuation algorithms facilitates the implementation of fire prevention planning. The availability of cartography of economic vulnerability of the forest ecosystems is fundamental for budget optimization, and to help in the decision making process.”