COS 5-2 - Sustainable pathways for shortleaf pine (Pinus echinata) restoration in uncertain climates

Abstract: Throughout the southeastern US, strip mining has left degraded and low productivity soils. Combinations of organic (OA) and microbial (MA) soil amendments can enhance restoration through increasing carbon sequestration, reducing erosion, and immobilizing heavy metals. In the face of climatic uncertainty, there is a need to understand how the sustainability of current restoration efforts may be impacted in the future to protect soil health and water quality. Precipitation uncertainty due to climate change may challenge the effectiveness of our existing restoration techniques. This study represents a comprehensive greenhouse experiment over one growing season to extend the findings of a current field trial to inform future reforestation efforts using shortleaf pine (Pinus echinata) with consideration to climate change under different moisture regimes: dry, average, and wet. Replicates across moisture treatments received the following amendments: OA, MA, OA+MA, unamended control, or control with no trees. Soil health indicators (electrical conductivity, pH, and carbon and nitrogen content), tree growth parameters (survival, ground line diameter, height), and soil-water fluxes (dissolved organic carbon, specific ultraviolet absorbance at 254 nm) were measured throughout the study.


This study suggests that the soil amendments significantly impacted all soil health indicators, tree growth parameters, and soil-water fluxes. The soil amendments mitigated negative changes in soil health indicators in the dry water regime. MA were especially successful in the dry water regime which had higher soil health parameters compared to MA in the average water regime. MA in the dry regime had 17% more soil C content, 8% more soil N content, and 22% higher electrical conductivity compared to MA in the average water regime. In general, the wet water regime had the greatest increases in tree growth parameters. However, soil amendments mitigated the negative impacts of drought stress as there were no differences in height, ground line diameter, and root to shoot ratio between the dry and average water regimes. Height for OA+MA in the dry water regime had 16% more height growth than the same treatment in the average water regime. The root to shoot ratio for MA and OA+MA in the dry regime was 65% and 73% higher respectively than in the same soil treatments in the average water regime. These changes support the idea that soil amendments are an option to support shortleaf pine growth on post-mined soils and could alleviate the stress related to future drought conditions.