Premium
Risk of white pine blister rust to limber pine in C olorado and W yoming, USA
Author(s) -
Kearns H. S. J.,
Jacobi W. R.,
Reich R. M.,
Flynn R. L.,
Burns K. S.,
Geils B. W.
Publication year - 2014
Publication title -
forest pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.535
H-Index - 49
eISSN - 1439-0329
pISSN - 1437-4781
DOI - 10.1111/efp.12065
Subject(s) - biology , logistic regression , canker , infestation , ecology , forestry , statistics , horticulture , geography , mathematics
Summary Cronartium ribicola , the introduced pathogen that causes white pine blister rust ( WPBR ), continues to spread to additional limber pine populations in the S outhern R ocky M ountains of C olorado and W yoming. Because WPBR can severely impact ecosystems, forecasts of its potential distribution and incidence would be useful to land managers. Site and climate data from long infested study areas in W yoming were fit with two regression models [logistic and classification and regression trees ( CART )] to determine the environmental conditions associated with the distribution of WPBR . These models were then used to map limber pine stands at risk of infestation by C . ribicola throughout W yoming (where it has long occurred) and C olorado (where it is just becoming established). Although variables representing vegetation and landform could identify infested plots, 1‐km‐scale climate variables for monthly temperature and moisture were better predictors of current WPBR distribution and were available for mapping expected future distribution across the region. Of 280 485 ha where limber pine was projected to occur in C olorado, 41% was forecast by the logistic model to be at risk of infestation, and 53%, by the CART model. Of an estimated 782 229 ha in Wyoming with limber pine, the logistic model projected 61% to be at risk; CART projected 79%. Additional regression models were fit with site and climate data to predict WPBR incidence (per cent of trees infected) and intensification (incidence/age of the oldest canker). Nearly one half of the plot‐to‐plot variation in incidence was explained using environmental variables readily available to land managers. Although mean plot incidence increased over time, mean intensification decreased 50% per decade. This work provides managers with several tools to reduce uncertainty over the expected distribution and incidence of WPBR , but surveillance and monitoring remain prudent activities for supplementing forecasts of WPBR epidemics.