Eastern conifer forests have historically been impacted by major abiotic (e.g., drought, windstorms, and flooding events) and biotic (e.g., insects and diseases) agents. These factors are becoming even more critical under climatic changes causing major alterations to forest structure and composition. We report on two studies in southern conifer forests that indicate that local and native factors can have considerable influence on the resilience of these ecosystems. In the first study, we determined if various abiotic (soil nutrients, slope, aspect, etc.) and biotic (root fungi and insects) factors are affecting loblolly pine health. Healthy and unhealthy pine plantations were sampled intensively in Georgia and Alabama. In the second study, we determined the extent, severity, and associated biota associated with dying and dead eastern white pine trees. Stands (40) were established and intensively sampled throughout southern Appalachian Mountains.
Results/Conclusions
In the first study, results indicate that while soil nutrients were similar between the healthy and unhealthy stands, Manganese was lower in unhealthy stands that also had higher silt content. Further, basal area and trees per acre, along with incidence of a root pathogen were higher in unhealthy stands. In the second study, results indicate that >50% eastern white pine trees are showing signs of moderate dieback with distinct canker formations on branches and bole. The smallest pine age class was most affected, though mature trees are also showing dieback. A native scale insect and canker fungi were associated with symptomatic pine trees throughout the range in a novel association likely due to climatic changes. Hence, mitigation measures for both abiotic and biotic factors are need in these ecologically and economically important pine ecosystems for their long-term integrity and sustainability.