Browsing by Subject "white pine"
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Item Climate-informed restoration of white pine: Impacts of seed source, planting site, and earthworms(2016-11) Mead, JordanHabitat suitability for forest species is expected to shift with changes in climate, resulting in new and altered species assemblages. These alterations will be most notable near species boundaries, where feedbacks between disturbance, regeneration and recruitment are especially sensitive to temperature. How forest ecosystems respond will depend on the rate of climate change, dominant disturbance regime, the arrival of suitable propagules and the ability of those propagules to survive local climate, herbivory, invasive species and interspecific competition. Local adaptation of tree populations has been well documented in common garden experiments and may have a significant impact on the regeneration and recruitment in disturbed forests. In Northern Minnesota, USA, forest-climate models predict large-scale shifts in forest cover, and climate-driven changes in forest regeneration have already been documented at ecotone boundaries. Local populations of white pine (Pinus strobus) that are expected to increase may not be able to survive and reproduce successfully due to population bottlenecks, slow migration rates, habitat fragmentation, and intense herbivory. This is coupled with reduced reproduction of other temperate species, such as maples (Acer spp.), by herbivory and introduced detritivores. Given the rate of climate change, the migration and evolution of locally adapted populations and species are expected to lag behind optimal climate. My work documents restoration of white pine to assess the effects of seed source climate and site attributes, such as light environment and earthworm abundance, on survival, growth and phenology of planted seedlings. I also investigate the impacts and abundance of non-native earthworms in disturbed areas, as well as the surrounding intact forest to look for interactions between these invaders and disturbance. This data could be further used to improve models and inform management that will help sustain forest health and productivity.Item Logging versus fire: How does disturbance type influence the abundance of Pinus strobus regeneration?(2004) Weyenberg, S A; Frelich, L E; Reich, Peter BEastern white pine (Pinus strobus) has decreased in abundance over the past century throughout the Great Lakes Region of North America, but the relative constraints placed on recruitment under contrasting disturbance regimes are not well understood. The objectives of this study were to determine the extent to which white pine could invade areas recently disturbed by fire or logging (within 10–28 years), and assess the relative limitations placed on recruitment by seed supply, microsite habitat, and competition. We compared white pine regeneration on 61 sites disturbed by fire or logging that were adjacent to intact mature stands that provided a seed source. White pine seedling and sapling densities declined with increasing distance from a seed source, and the rate of decrease was determined by the interaction between seed supply and variation in number and quality of safe sites. For a given combination of seed source and site, white pine seedlings were three times more abundant on burned than logged sites. White pine seedlings grew into the sapling size class more often on burned than logged sites due to lower shrub cover on burned sites. At 25 years after disturbance, regeneration densities of white pine sufficient to achieve eventual future dominance occurred up to 80 m and 20 m from the edge of mature white pine stands after fire and logging, respectively. To attain a similar level of white pine stocking after disturbance, three to four times as many patches of mature white pine need to be left after logging than after fire.Item Pathways in old-field succession to white pine: Seed rain, shade, and climate effects(2005) Dovčiak, Martin; Frelich, Lee E; Reich, Peter BTrees slowly colonize old fields on sandy outwash in the prairie–forest ecotone of the north-central United States, and in the absence of fire, succession is expected to proceed toward oak woodland. We analyzed whether a case of unusually rapid and spatially extensive invasion by white pine (Pinus strobus) could be explained by the presence of specific temporal or spatial opportunity windows suitable for such invasion. We tested whether the invasion was temporally restricted to the period immediately after abandonment or to periods of favorable climate, and whether it was spatially restricted to areas of high seed rain or high forest-edge shade. White pine invasion into the field occurred in two waves separated from each other by a 1987–1989 drought period. The first wave (1980– 1985) occurred during a period of average climate and led to the establishment of dense sapling patches in shade near forest edges. The second wave (1991–1994) occurred during a period of high precipitation and cooler than normal temperature, and resulted in colonization of the unshaded field center. In addition to the two temporal windows, white pine invasion occurred within two spatial windows: in areas highly sheltered by forest edge and in areas receiving high white pine seed rain. Overall these windows produced three different successional pathways: (1) a slow, creeping white pine invasion into highly shaded areas with low seed rain near forest edges; (2) a rapid, discrete-step invasion in areas where seed rain was abundant enough to overcome mortality in lower shade and where early arrivals facilitate filling in by later arrivals; and (3) a deferred invasion in the field center where low seed rain and lack of shade allowed the persistence of a grassland stage until favorable climate resulted in a white pine recruitment pulse. Temporal variation in climate can accelerate or decelerate any of the three successional pathways.Item Report on the Timberlands of the Northern and Cloquet Lumber Companies, St. Louis County, Minnesota(Bureau of Forestry, 1903-06) Chapman, C.S.The study of the timberlands of the Northern and Cloquet Lumber Companies, the results of which are presented in this report, was made primarily in order to determine whether future crops of merchantable timber may be harvested from lumbered lands within a reasonable time. The study undertook to devise practical modifications of present methods of logging which will hasten the production of a second crop on cut-over lands.