Summary of findings from the Great Plains Tree and Forest Invasives Initiative

Abstract

The Great Plains Tree and Forest Invasives Initiative (GPI) was a cooperative effort of the U.S. Forest Service and state forestry agencies in Kansas, Nebraska, North Dakota, and South Dakota, with a primary goal of evaluating the tree resources throughout the four-state region as a preparedness measure for the arrival of invasive pests, such as the emerald ash borer (Agrilus planipennis Fairmaire). The GPI assessed the characteristics of the resource known as trees outside forests (TOF), or trees that occur on lands that do not meet the Forest Inventory and Analysis (FIA) definition of forest land. Data, including tree number, species, diameter, height, canopy health, and windbreak function, were collected on 1/6 acre plots. Across the four-state region, TOF account for almost half of the total area of all tree resources. Forest land covers about 6.4 million acres, while land associated with TOF covers 5.1 million acres. Approximately 56 percent of the land use associated with TOF is agricultural. Over one-third (36 percent) of the acres and more than half (55 percent) of the trees identified as TOF function as windbreaks of some sort, with agricultural windbreaks being most common. Of the windbreaks, 72 percent are in poor to fair condition and 48 percent are between 25 and 50 years old. As the existing windbreaks continue to age, fewer young trees are filling the gap. Just over half of the trees (53 percent) on TOF lands occur naturally while the remainder have been planted, and 86 percent of TOF trees are located in rural areas. Many tree species are present in the four-state region, but ash trees (Fraxinus spp.), the emerald ash borer’s target of choice, are the most prevalent. This information will help natural resource professionals plan conservation and restoration efforts.