A biogeochemical analysis of the Pocono till barrens and adjacent hardwood forest underlain by Wisconsinan and Illinoian till in northeastern Pennsylvania

Abstract

We assessed soil and vegetation nutrient capital in the landscape mosaic of till barrens and hardwood forests on the Pocono Plateau in northeastern Pennsylvania. These shrublands, which contain an unusual abundance of rare species, occur primarily on Illinoian-aged glacial till, though some patches grow on Wisconsinan till. We hypothesized that barrens soil and vegetation contain smaller quantities of nutrients than forest soil and vegetation, and under the same vegetation, Illinoian till soils have a smaller nutrient content than Wisconsinan till soils. We measured pH, total C and N, and exchangeable Ca, Mg, K, and Al content of the soils and determined C, N, Ca, Mg, K, and P content of the vegetation. Litter and soil organic matter in the barrens have a higher C/N ratio than the forest. The Illinoian barrens Oa horizon is thicker and contains a greater quantity of exchangeable mineral nutrients than the other Oa horizons. Differences in vegetation nutrient capital strongly mirror differences in biomass. Our results show no strong association of parent material with soil or vegetation nutrient capital. Instead, they suggest that plant community characteristics, not soil nutrient availability, shape the landscape pattern of barrens and forest, particularly plant-driven positive feedbacks primarily involving fire frequency. We assessed soil and vegetation nutrient capital in the landscape mosaic of till barrens and hardwood forests on the Pocono Plateau in northeastern Pennsylvania. These shrublands, which contain an unusual abundance of rare species, occur primarily on Illinoian-aged glacial till, though some patches grow on Wisconsinan till. We hypothesized that barrens soil and vegetation contain smaller quantities of nutrients than forest soil and vegetation, and under the same vegetation, Illinoian till soils have a smaller nutrient content than Wisconsinan till soils. We measured pH, total C and N, and exchangeable Ca, Mg, K, and Al content of the soils and determined C, N, Ca, Mg, K, and P content of the vegetation. Litter and soil organic matter in the barrens have a higher C/N ratio than the forest. The Illinoian barrens Oa horizon is thicker and contains a greater quantity of exchangeable mineral nutrients than the other Oa horizons. Differences in vegetation nutrient capital strongly mirror differences in biomass. Our results show no strong association of parent material with soil or vegetation nutrient capital. Instead, they suggest that plant community characteristics, not soil nutrient availability, shape the landscape pattern of barrens and forest, particularly plant-driven positive feedbacks primarily involving fire frequency.Résumé : Nous avons évalué le stock de nutriments dans le sol et la végétation dans une mosaïque de paysage de tills improductifs et de forêts feuillues sur le Plateau Pocono dans le nord-est de la Pennsylvanie. Ces prairies boisées où on retrouve une abondance peu commune d'espèces rares occupent principalement le till glaciaire de l'Illinoien, bien que certains îlot...

Native tree seedling growth and physiology responds to variable soil conditions of urban natural areas

“…Across all species, foliar N concentrations were consistently highest in seedlings grown in native till soils, and foliar N had a significant positive effect on PI ABS on all tree species except serviceberry. The black birch, red oak, and silver maple seedling foliar N concentrations were lower than published values or thresholds for deficiency (Pardo et al 2004; Castro et al 2007; Showalter et al 2010), while serviceberry foliar N was comparable to published values found in saplings at New York City restoration sites and elsewhere (Pardo et al 2004; Wibiralske et al 2004; Falxa‐Raymond et al 2014). However, foliar N did not have a positive effect on seedling biomass of any species and had a significant negative effect on red oak and serviceberry biomass (primarily driven by declines in foliar biomass).…”

Chemical properties of upland forest soils in the Catskills region

“…These values are lower than other reported masses for the Catskills and the Pocono region of Pennsylvania. The average O‐horizon mass ranged from 12 to 20 kg/m 2 at four sites sampled in the early 1990s in the Pocono Barrens . A study conducted in the Catskills in 2000–2003 reported average O‐horizon masses of 6–10 kg/m 2 .…”

The Quantitative Soil Pit Method for Measuring Belowground Carbon and Nitrogen Stocks

“…Many studies (e.g. Kulmatiski et al, 2003;Wibiralske et al, 2004) used pits only 50 cm square (0.25 m 2 ), which expedites the process, but limits the total depth that can be excavated cleanly; our 0.5 m 2 pits allow a person to work from inside the pit. Richter et al (1989) excavated small pits, only 0.05 m 2 , to a depth of 40 cm.…”