Date of Award

Fall 12-2017

Level of Access Assigned by Author

Campus-Only Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Forest Resources

Advisor

Shawn Fraver

Second Committee Member

William Livingston

Third Committee Member

Seanna Annis

Additional Committee Members

Mindy Crandall

Isabel Munck

Abstract

Throughout North America, eastern white pine (Pinus strobus L.) is one of the most ecologically and economically significant conifer species. In recent years, however, the species has experienced an increase in damage associated with Caliciopsis canker, a fungal disease thought to be caused by the pathogen Caliciopsis pinea Peck. The disease is associated with severe resinosis, crown thinning, cankers, and bark cracks/fissures which can cause increased damage and loss in eastern white pine stands. Yet Caliciopsis canker is not the only emerging health issue. The native eastern white pine bast scale (Matsucoccus macrocicatrices) and a complex of foliar pathogens known collectively as White Pine Needle Damage have become increasingly common in eastern white pine forests, and in combination with Caliciopsis canker pose a serious health concern to the species range-wide. By presenting past, present, and future health issues, along with known silvicultural practices, this dissertation summarizes the current health status of eastern white pine in North America. Subsequent chapters focus on the biological, ecological, and economic impact of one specific emerging health issue: Caliciopsis canker. Results confirm that C. pinea is associated with and likely one of the primary agents associated with Caliciopsis canker damage on eastern white pine, although an additional 32 fungal taxa were identified. The majority of these taxa occurred at low frequencies, however Dermea sp. and Diplodia sp. occurred at approximately the same frequency as C. pinea (10%), indicating a need for further research into the interaction of these pathogens on eastern white pine. Caliciopsis canker damage was associated with smaller, less vigorous trees already predisposed to other stressors. As canker incidence and occurrence increased, tree growth, crown health, and functional sapwood area all decreased. Consequently, economic analyses show that Caliciopsis canker damage resulted in average lumber revenue losses of 2.3%. While these results demonstrate C. pinea is associated with Caliciopsis canker damage, and that this disease can cause significant damage in eastern white pine trees, results also show that carefully timed management operations in combination with better quality site conditions have the potential to minimize damage and loss associated with this emerging health issue.

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