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  • Thursday, April 2, 2015
  • 1:30 PM–2:20 PM
  • Science Building 010

Jon Knott and Deanna Geelhoed

Jon Knott
Forty Years of Forest Development in the Calvin College Ecosystem Preserve

In 1974, the diameter at breast height (DBH) was measured for all trees in the Calvin College Ecosystem Preserve by a Prof. Alan Gebben and John Ubels (a recent graduate). Each tree was categorized by species, size class, and status (e.g.dead-standing, live-leaning, etc.). The trees have been re-measured on a 5 year interval. This summer (2014) we measured all of the trees in the original area (2.0 ha) and expanded the sampling area to include previous “edge” areas (2.0 ha; 4.0 ha total). We measured DBH at 1.3m and 1.5m above ground for all trees >2” DBH. We used a ceptometer (Decagon LP-80) to measure the light level—Photosynthetically Active Radiation (PAR) and Sunfleck (% of the meter in sunlight)—in each quadrat. In total, we measured 3009 trees >2” DBH, and counted 8652 saplings (in the original quadrats). We found that most of the white ash (F. americana) have died in the past 20 years due to Ash Yellows disease and the emerald ash borer (120 trees present in 1994, only 8 remain this year). We also found that the original study area has been progressing towards, and now seems to be stable at a Beech-Maple climax community. American Beech (F. grandifolia) and Sugar maple (A. saccharum) have shade-tolerant saplings which might be related to low light level and high canopy thickness. Finally, we also found that the edge areas had many more earlier successional species with higher importance values, such Red Oak (Q. rubra) and Wild Black Cherry (P. serotina).

Deanna Geelhoed
Native Habitats in Urban Landscapes: Prince Prairie on Calvin's Campus

Increased human development has led to decreased native landscapes and biodiversity. In urban areas this loss can be combated by establishing green spaces comprised of native plants and trees. These local flora have many benefits including decreased fossil fuel use, decreased herbicide and insecticide use, wildlife habitat restoration, increased trophic support, storm water and erosion control, genetic diversity enhancement, and pollination attraction. This study’s aim was to determine how to install a prairie in an urban area to produce optimal growth with minimal maintenance. In 2013, the 60-plot Prince Prairie was installed on Calvin College’s campus to compare the growth of five different prairie species (Sedge, Sand Coreopsis, Pasture Rose, Northern Blazing Star, and Little Bluestem) in six different soil treatments. These treatments consisted of combinations of rototilled or non-rototilled ground and sand:organic soil compositions. The 2014 data show all prairie species grew optimally in the sandiest soil ratios. Growth for rototilling was species dependent; some species preferred the loose rototilled plots, while others preferred non-rototilled soil. There was no correlation between weed mass and soil ratio, rototilling, or the plot’s position in the prairie. Taking these results, future prairie restoration projects can know that while rototilling should be species dependent, all the species studied yielded optimal growth in the sandiest soil composition ratio.

 

April 2015
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