The ecological and economic determinants of eastern redcedar (Juniperus virginiana) encroachment in grassland and forested ecosystems: A case study from Oklahoma

Abstract

Frequent fires were used as a management tool to maintain prairies, savannas, and woodlands in the southern Great Plains of the United States. However, fire exclusion beginning in the mid-1900s allowed for the establishment and growth of fire-intolerant species such as eastern redcedar (Juniperus virginiana: ERC) beyond their naturally occurring habitats. Apart from the reduction in burning, wide soil and climate adaptability, and seed dispersal by birds have facilitated the expansion of ERC in the southern Great Plains. The encroachment of ERC has caused heavy ecological and economic losses to Oklahoma and thus has been a major management concern for the past few decades. This study utilized count data modeling to analyze USDA Forest Service's (USFS) Forest Inventory and Analysis (FIA) data to investigate the relationship between available ecological and economic factors and the abundance of ERC in grassland and forested ecosystems of Oklahoma. The results suggested that low site productivity, high basal area, dense canopy, and silt loam soil texture significantly increase the abundance of ERC on a given site. The results also indicated that the rate of ERC encroachment is 3.3% higher in the softwood and 2.0% higher in the miscellaneous forests, compared to the hardwood forests. However, the economic variables of the study such as ownership type, adoption of active management, and proximity to a metropolitan area did not show a significant relationship to the abundance of ERC.