These long-term plots were first sampled in the 1930's or 1940's. Sampling generally consists of dbh and/or height censuses. Although many trees were given identifier tags when the plot was established, many of those tags have been lost.
Plots fall into several groups:
The BS32 plots, placed in mixed swamp conifers, study growth rates of young trees.
The BS34 plots test the effect of thinning on residual tree growth (A) in mixed hardwoods, with plot B acting as a control.
The BS40 plots (E=.2 acres, F=.45 acres) observe the growth rate of trees in a red pine stand which was pruned in 1940.
The BS42 plots, placed in a red pine-dominated forest, compares the growth of conifers in a 1 acre plot (B) where trees were pruned and competing aspens and birches were cut, with 0.5 acre control plots (A, C) that lie adjacent on B's east and west sides.
The BS46 plot measures the height and DBH of planted red, jack, and scotch pine in a plantation along Greenstar road.
To add: BS40A (hemlock plot, digital but not yet public), BS40B.
Long term study plots which track DBH (and in some cases, height) of tagged trees through time under a variety of treatments/no treatments. Trees recruited after the plot was established may or may not have been tagged.
Understanding environmental factors related to exotic earthworm distributions across invasion stages (i.e., introduction, colonization, regional spread) is critical for assessing long-term impacts on previ- ously earthworm-free forests. Studies following earthworm community establishment in North America, however, remain limited. We address this by characterizing historical and current exotic earthworm distributions in a regionally representative aspen-dominated forest, where their presence was first documented in the early 1900s. We map historic earthworm distribution records in a 360-km2 area surrounding our current study site, and re-analyze data collected nearly 60 years ago to inform contemporary associations between species densities and environmental factors. Field surveys were conducted over two years (2008e2010) using 10 permanent plots, with concurrent measurements of environmental ‘effect factors’ determined by large-scale ecosystem processes (leaf litter inputs, soil physical properties, soil C and N content), and environmental ‘response factors’ likely impacted by earthworm activity over short time scales (annual litter mass loss and soil isotopic values). Present-day communities included five exotic species with varying densities: Lumbricus rubellus ! Lumbricus terrestris >> Dendrobaena octaedra ! Aporrectodea spp. (Aporrectodea trapezoides þ Aporrectodea cal- iginosa). These species were also present in the landscape in the early to mid-1900s though shifts in species composition, particularly the movement of L. terrestris into upland forest soils, were evident. Over two years, earthworm community composition did not show strong temporal or spatial trends characteristic of incipient invasions. However, species-specific associations with environmental factors were observed: L. terrestris and L. rubellus densities were positively associated with soil C and N content, Acer rubrum (red maple) inputs, and soil moisture; and were negatively associated with Pinus strobus (white pine) inputs. D. octaedra, and Aporrectodea spp. densities were positively associated with % sand; and negatively associated with plot-to-road distance. Soil moisture and texture were significant drivers of earthworm species abundance in historical surveys, though associations with soil C were only evident for Aporrectodea spp. Contemporary associations between earthworm species and soil C and N content suggest greater nutrient limitation in upland forest soils, while the importance of plot- to-road distance suggests the persistence of dispersal limitation and repeated introductions as a mechanism maintaining population densities. Species-specific associations with environmental response variables were also observed, where: surface soil d13C depletion was associated with Apor- rectodea spp. and D. octaedra biomass; d15N enrichment was associated with total earthworm biomass, but negatively associated with L. rubellus biomass; and increased leaf litter mass loss was associated with L. terrestris and juvenile biomass. As soil C and N pools were not higher in plots with higher earthworm biomass, these results suggest earthworm activity may influence soil nutrient cycling by decreasing turnover times of nutrient pools over the long-term. Our results characterize exotic earthworm distributions at scales relevant to forest ecosystem processes, and allow for future extrapolation of laboratory and controlled field studies assessing impacts on soil nutrient cycling across northern temperate forests.
Electroshocking, Honda EU, 2000i gasoline-powered generator
Costech elemental analyzer 1030
Thermo Finnigan Delta Plus XL
ICP-OES PerkineElmer Optima 2000 DV
CS620 HydroSense, Campbell Scientific
Several researchers have mapped the dominant forest cover of UMBS properties at several points in history. The original maps were created using on-the-ground reconnaissance and traditional surveying techniques. Most maps describe only dominant canopy, except "1970 vegetation landcover" which describes, overstory, midstory, understory, and groundcover, along with information about the size of aspen and bracken fern.
Maps were scanned and digitized using ArcGIS tools in 2014. Map creation and digitization methods were both subject to error, so these data should be treated as spatially imprecise.
Various paper land cover maps were digitized using ArcGIS tools.