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Advisor(s)
Abstract(s)
We used the Ripley’s K function, a second order analysis method, to describe the spatial dynamics of tree
infection caused by chestnut blight (Cryphonectria parasitica (Murrill) Barr) in sweet chestnut orchards. Our
research question was whether the location of infected trees affected the spatial pattern of spread of the
disease in orchards. We also wanted to know whether existing patterns could be associated with management
practices. Surveys of infections and mortality caused by chestnut blight were conducted at the tree level in 4
plots in 2003, 2004, 2005, and 2009 in the Curopos parish, Vinhais, Portugal. We applied the Ripley’s K function
to locations of diseased (infected and dead) trees to look for spatial pattern. We compared locations from
successive dates using the bivariate form of the K function to look for spatial association of diseased trees in
consecutive years. We found both random and aggregated patterns of infected trees in the beginning of the
study period and significant association of infected trees between successive dates, particularly at short
distances. The results indicate that fast, short distance spread of chestnut blight occurs within orchards which
can possibly be explained by both natural propagation of the disease and management practices.
Description
Keywords
Ripley’s K function Cryphonectria parasitica Vinhais Landscape ecology
Citation
Azevedo, J.C.; Coelho, V.; Castro, J.P., Spínola, D.; Gouveia, E. (2010). Spatial dynamics of chestnut blight disease at the plot level using the Ripley’s K function. In Azevedo, João; Feliciano, Manuel; Castro, José; Pinto, Maria Alice (Ed.) - Book of abstracts of the IUFRO Landscape Ecology Working Group International Conference: Forest Landscapes and Global Change ‐ New Frontiers in Management, Conservation and Restoration. Bragança: IPB, IUFRO. ISBN 9789727451111