Browsing by Subject "Black Spruce"

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    Improving Knowledge of Permafrost-Affected Soils in Alaska - Field Data Collection and Sampling Design to Support Current and Future Soil Survey Initiatives
    (2020-12) Sousa, Michael
    Lands in the United States without detailed soil survey coverage are considered "not complete" (NOTCOM). There are currently approximately 430 million acres of NOTCOM remaining in the United States, with Alaska making up more than 70% of this remaining area. The first part of this work is a collaborative sampling of black spruce forests and associated permafrost-affected soils in the central Copper River basin. After sampling sites under burned and unburned areas, we assess trajectories of soil carbon, permafrost and vegetation change following fire to inform future management strategies. The second portion of this work examined the utility of implementing a Conditioned Latin Hypercube Sampling (cLHS) methodology in order to locate optimal sampling locations for future study. The cLHS used in this study was constrained by an inclusive cost layer representing an aggregation of real-world costs associated with travel within the Yukon-Kuskokwim Delta study area located in south western Alaska.
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    Influence of Eastern Dwarf Mistletoe and Fungi on Regeneration Health and Composition in Lowland Black Spruce Post-Harvest
    (2022-06) Gorman, Alexander
    Black spruce (Picea mariana [Mill] Britton, Sterns & Poggenb) is a dominant and wide-ranging North American boreal forest species. It reaches its southwestern range limit in Minnesota, USA. Forest managers in Minnesota have become increasingly aware of how eastern dwarf mistletoe (Arceuthobium pusillum [Peck]) (EDM) may be influencing the ability of black spruce to regenerate after harvest naturally. This study aimed to explore regeneration dynamics in black spruce stands, quantify residual tree density and impact from EDM, and quantify EDM infestation in neighboring stands. Ten stands were surveyed over three years in northern Minnesota pre-and post-harvest. Eastern larch comprised almost 70% of the regeneration in EDM infected stands and over 50% of the regeneration in the uninfected stands, suggesting that the light intensive environment is favorable for eastern larch regeneration. A significant difference was observed between the total percentage of black spruce regeneration recorded, with uninfected stands having a higher proportion of black spruce (p = 0.06). The diameter at breast height in inches and the square feet of basal area per acre were greater in stands with EDM infections due to residual trees left in clumps. While clear-cuts are a viable option for mitigating EDM, the disease will continue to occur if the 5-foot cutting rule is not followed. Likewise, neighboring stands can be a source of future EMD infections even if the 5-foot cutting rule is efficiently applied within a stand. Management decisions for EDM should consider infection both within the stand and at the broader landscape level (neighboring stands) when developing management recommendations. Additionally, twelve actively managed black spruce stands in Northern Minnesota, USA, were sampled to understand better the diversity and abundance of fungi present in black spruce bogs affected by eastern spruce dwarf mistletoe. The twelve stands were divided evenly between recently harvested (six stands) and unharvested (six stands); additionally, half of the harvested and unharvested stands were infected with eastern spruce dwarf mistletoe, and half were uninfected. Due to the potential for fungal infections to act as secondary disturbance agents that could expedite black spruce mortality, an emphasis was placed on investigating the presence of fungal pathogens in the Basidiomycota. Forty distinct fungal species were identified across all twelve study stands. Of all the species identified, less than half (43%) were determined to be fungal pathogens. No significant differences in fungal diversity were found between the study treatments. Additional work in black spruce systems should increase understanding of potential above and below ground disturbance agents.