Distribution of Ash

Fig. 1 - Ash basal area

Analysis of the distribution of ash at two scales showed two facts: there is a lot of ash available to the insect, and it is distributed throughout the Eastern United States. Consequently, the EAB threat is real for most communities and rural locations throughout the region.

Coarse-Level Analysis of Ash for Eastern United States

Fig. 2 - Percent forest cover

Fig. 3 - Ash availability

The map of ash BA (including white, green, black, and blue ash) per unit area of forest shows there is a great deal of ash in the woodlots and small forests common within the current range of the EAB (southern Michigan, northern Ohio, northeastern Indiana) (Figure 1). However, the amount of forest in that zone is limited (Figure 2), so the total available ash is less compared to the more forested regions (Figure 3). Of major concern is the large amount of ash available just south of Lake Erie (northeast Ohio, northwest Pennsylvania) and Lake Huron (western New York). The western edge of this zone is just now being reached by the EAB.

These maps show a high level of ash availability in the zones surrounding the borer’s current range, indicating a difficult control task ahead.

Fig. 4 - Ash proportion by state

Figure 4 shows a map with the proportions of various genera of trees in each State of the Eastern United States. Ash comprises a significant proportion of basal area across the Northern States, but is less prevalent in the Southeastern States.

Fine-Scale Analysis of Ash for Ohio

Fig. 5 - Ash availability for Ohio

The fine-scale analysis for Ohio, using 30-m data and plot information, shows an estimate of the urban and riparian zones with levels of ash (BA) (Figure 5). Most of the area shown in Figure 5 is agricultural land, but ash is maintained in the landscape even in these croplands along roadsides, ditches, and small wetlands. There are also numerous woodlots, many of which contain high proportions of ash.