Background:
Lodgepole pine (Pinus contorta) is a widely distributed tree species of economic and ecological importance (Peet 2000, Image 2). Lodgepole pine ecosystems are strongly influenced by both natural and anthropogenic disturbances such as fire, Mountain Pine Beetle (Dendroctonus Ponderosae; hereafter MPB) outbreak and clear-cut logging (Romme and Knight 1981, Peet 2000, Anderson 2003).
Lodgepole pine (Pinus contorta) is a widely distributed tree species of economic and ecological importance (Peet 2000, Image 2). Lodgepole pine ecosystems are strongly influenced by both natural and anthropogenic disturbances such as fire, Mountain Pine Beetle (Dendroctonus Ponderosae; hereafter MPB) outbreak and clear-cut logging (Romme and Knight 1981, Peet 2000, Anderson 2003).
In MPB infested stands in Western Alberta minimal lodgepole pine regeneration has been observed whereas pine regeneration is abundant in harvested or burned stands, suggesting that lodgepole regeneration may respond differently to different disturbances. However, it is unclear what mechanisms contribute to regeneration differences among disturbed stands. Understanding how lodgepole pine responds to disturbance and the role of soil fungal communities in that response becomes increasingly important in light of the past, present and future impacts of climate change on forest disturbances (Flannigan et al. 2005, Balshi et al. 2009, Price et al. 2013).
Past work has found soil microbial communities to be a critical component in the ability of forests to regenerate following a disturbance (Perry et al. 1989). A functional obligate symbioses exists between ectomycorrhizal fungi (Hereafter, ECM) and many pines where ECM fungi aid in the absorption of nutrients and water unavailable to the pine and in return the host pine allocates sugar (carbon) to the ECM fungi (Perry et al. 1989, Read 1998, Baar et al. 1999, Karst et al. 2014). In addition, pathogenic and saprotrophic fungi also have important interactions with pines and as a result, fungal community composition is important for the survival of many pines on disturbed sites, lodgepole pine included (Perry et al. 1989, Simard and Durall 2004, Karst et al. 2014).
The recent eastward expansion of MPB into lodgepole pine forest ecosystems in Western Alberta has created a cascading impact on the below ground soil fungal community (Treu et al. 2014, Karst et al. 2015, Pec et al. 2016). In addition, seedlings planted in beetle-killed stands had reduced survival when compared to undisturbed control sites (Karst et al. 2015). Mortality from MPB is not the only disturbance that alters soil fungal community composition. Disturbances such as wildfire and clear cut logging alter the fungal communities of a forest stand, furthermore the way each disturbance alters the fungal composition is different (Visser 1995, Perry et al. 1989, Dahlberg 2002, Jones et al. 2003, Cairney and Bastias 2007, Twieg et al. 2007, Barker et al. 2013, Treu et al. 2014). In order better understand the mechanisms involved in lodgepole pine regeneration following disturbance, specifically the role of soil fungal communities in Lodgepole pine regeneration, I will investigate how lodgepole pine seedlings grow when their soils are inoculated with soils from sites disturbed by wildfire alone, timber harvesting alone, MPB outbreak alone, MPB outbreak plus timber harvesting and undisturbed sites in western Alberta. However, due to wide geographic distribution of lodgepole pine and the importance of the four disturbances throughout the range of lodgepole pine I suspect that my work will have application beyond western Alberta (Anderson 2003).
Past work has found soil microbial communities to be a critical component in the ability of forests to regenerate following a disturbance (Perry et al. 1989). A functional obligate symbioses exists between ectomycorrhizal fungi (Hereafter, ECM) and many pines where ECM fungi aid in the absorption of nutrients and water unavailable to the pine and in return the host pine allocates sugar (carbon) to the ECM fungi (Perry et al. 1989, Read 1998, Baar et al. 1999, Karst et al. 2014). In addition, pathogenic and saprotrophic fungi also have important interactions with pines and as a result, fungal community composition is important for the survival of many pines on disturbed sites, lodgepole pine included (Perry et al. 1989, Simard and Durall 2004, Karst et al. 2014).
The recent eastward expansion of MPB into lodgepole pine forest ecosystems in Western Alberta has created a cascading impact on the below ground soil fungal community (Treu et al. 2014, Karst et al. 2015, Pec et al. 2016). In addition, seedlings planted in beetle-killed stands had reduced survival when compared to undisturbed control sites (Karst et al. 2015). Mortality from MPB is not the only disturbance that alters soil fungal community composition. Disturbances such as wildfire and clear cut logging alter the fungal communities of a forest stand, furthermore the way each disturbance alters the fungal composition is different (Visser 1995, Perry et al. 1989, Dahlberg 2002, Jones et al. 2003, Cairney and Bastias 2007, Twieg et al. 2007, Barker et al. 2013, Treu et al. 2014). In order better understand the mechanisms involved in lodgepole pine regeneration following disturbance, specifically the role of soil fungal communities in Lodgepole pine regeneration, I will investigate how lodgepole pine seedlings grow when their soils are inoculated with soils from sites disturbed by wildfire alone, timber harvesting alone, MPB outbreak alone, MPB outbreak plus timber harvesting and undisturbed sites in western Alberta. However, due to wide geographic distribution of lodgepole pine and the importance of the four disturbances throughout the range of lodgepole pine I suspect that my work will have application beyond western Alberta (Anderson 2003).
Research objective:
My research objective is to determine if seedlings grow and preform differently when inoculated with fungi form different disturbed sites. Specifically this work will investigate several important factors for successful seedling regeneration; seedling height, biomass, nutrient composition and the way seedlings allocate carbon (sugars) to soil fungal operational taxonomic units (OTU) to determine if these factors change with disturbed soil inoculation treatment.
Image 4 (Below): Graphical depiction of the objective of this research.
My research objective is to determine if seedlings grow and preform differently when inoculated with fungi form different disturbed sites. Specifically this work will investigate several important factors for successful seedling regeneration; seedling height, biomass, nutrient composition and the way seedlings allocate carbon (sugars) to soil fungal operational taxonomic units (OTU) to determine if these factors change with disturbed soil inoculation treatment.
Image 4 (Below): Graphical depiction of the objective of this research.
Expected Results:
I expect that soil fungal communities are an important factor in the regeneration differences observed in disturbed lodgepole pine stands. As a result, I anticipate that differences in soil fungal communities among disturbed soil inoculation treatments will result in significant differences among treatments in the composition of fungal OTUs that receive carbon (sugar) from seedlings as well as seedling height, biomass and nutrient composition. Specifically, based on observations of lodgepole pine regeneration I anticipate control sites to have the greatest height, highest nutrient composition and greatest biomass followed by timber harvesting alone, wildfire alone, MPB plus timber harvesting and lastly MPB alone.
I expect that soil fungal communities are an important factor in the regeneration differences observed in disturbed lodgepole pine stands. As a result, I anticipate that differences in soil fungal communities among disturbed soil inoculation treatments will result in significant differences among treatments in the composition of fungal OTUs that receive carbon (sugar) from seedlings as well as seedling height, biomass and nutrient composition. Specifically, based on observations of lodgepole pine regeneration I anticipate control sites to have the greatest height, highest nutrient composition and greatest biomass followed by timber harvesting alone, wildfire alone, MPB plus timber harvesting and lastly MPB alone.
Images Cited:
- Image 2: "Atlas of United States Trees" by Elbert L. Little, Jr.
- Image 3: courtesy of Jean Carlo Rodriguez Ramos