Ash Phloem Reduction Model Examples
Tara L. Eberhart, Andrew J. Storer, Linda M. Nagel
Examples of Data Entry
example in Figure 1 shows real stand data that has been entered, with the %
Surface Area that the Trees per
Figure 1 – Input Page with Example data filled in
Area Column - The column to the
right of the green Trees per
Relationship Cumulative Surface Area and DBH charts & Target % tables – Notice there are two output charts given with cumulative surface area, one descending (on top) and one ascending (on bottom of the page).
Figure 2 – 2 Output charts
The first chart corresponds with most common type of diameter limit harvesting of retaining small trees, which is removing all trees above a specified diameter at breast height. This chart matches up with the first table on the top left Retaining Small Trees that shows what the specific diameter limit is when targeting a certain percent removal of ash surface area as shown in Figure 1. In this example, to remove 95 % of the surface area available to EAB, all ash trees greater than 4.4 inches should be removed.
The second chart (Figure 3) has a positive slope with the cumulative surface area ascending. This chart uses the same data as the first one, but is showing what the diameter limit harvest would be to remove smaller trees and retain large diameter trees. The user will see that the diameter limits shown in the top table on the right to retain large trees are much larger than in the table to retain small trees.
Figure 3 – Bottom output chart to Retain Large Diameter Trees
With this type of harvesting, the forest manager can still remove a target amount of surface area or phloem available to emerald ash borer but retain seedlings (trees to small to be cut at all) and the larger diameter trees. The diameter limit given for this type of harvesting indicates the size at which trees are left rather than cut, so all trees less than the specific diameter are removed. Using this example, to retain large trees and still remove 95 % of the ash surface area, all trees less than 18.8 inches should be removed.
The same data entry applies to the 1” diameter class
model. In Figure 4, the 1” inch diameter classes have been filled in using
Figure 4 – Example using 1 inch class
Figure 5 – Examples using 1 inch class for large tree retention