SOIL PROPERTIES IMPEDE REFORESTATION OF ABANDONED MINE SITES IN CUYAHOGA VALLEY NATIONAL PARK

The Cuyahoga Valley National Park (CUVA) was established in 1974 as a National Recreation Area. At that time, park staff aimed to reclaim 40 degraded sites within CUVA. This included restoring abandoned slopes to more natural grades and seeding them with a mix of native and non-native grasses, legumes, and woody plants. Plants were chosen to prevent erosion, improve water quality, and be visually appealing. It was projected that most non-native species would give way to native woody species and allow for natural succession to occur within 20 years. While measured success was documented by the 1990s in the form of decreased erosion, increased plant life, and improved water quality, non-woody and invasive plants continue to dominate. In 2016, CUVA launched a new project, in collaboration with Kent State University, to assess present-day site conditions, determine an appropriate remediation, and lead a renewed effort to reforest five disturbed sites.

Five abandoned mine sites and four forested reference areas of similar location, slope, and aspect were chosen for this study. At these sites, we have collected 205 bulk density soil samples and 289 soil probe samples for grain size and chemistry analyses and have performed 66 infiltration rate measurements to determine saturated hydraulic conductivity (Ksat). Surface bulk density (0-5 cm) is not significantly different between the mined sites and the forest locations. However, preliminary bulk density measurements taken at 30 cm depths exceeded 1.8 gcm^-3. According to the Natural Resources Conservation Service, values this high are known to restrict root growth. There is also a marked difference in soil acidity between the forested areas (pH 3.6-6) and the mine sites (pH 7-8). Reference areas have Ksat between 1.4E-05 ms^-1 and 1.6E-05 ms^-1, while mine sites have generally lower values. For example, one site, Dover, had a Ksat of 8.3E-06 ms^-1.

Deep ripping was conducted at Dover in September 2017 to improve drainage and root penetration. We are also treating invasive plants with herbicide and have planted over 1,800 native trees with the help of over 500 volunteers. Ksat within rips increased by 4-40 times over pre-ripping conditions, while between rips Ksat was unchanged. Tree survival and health are being monitored.