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 % Phloem
Basal 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 Phloem Basal Area and DBH charts & Target % tables – Notice there is one output chart given with cumulative phloem basal area, with the slope descending to show the relationship and find the diameter limit to retain small trees. The 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 6.1 inches should be removed.
The second table of diameter limits uses 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.
With this type of harvesting, the forest manager can still remove a target amount of 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 20.9 inches should be removed.
same data entry applies to the 1” diameter class model. In Figure 2, the 1”
inch diameter classes have been filled in using Trees per
Metric data can be entered and applied the same way by choosing the metric versions of the model to enter data, depending on the type of data the forester has available, either 2 cm or 1 cm size classes of ash trees per acre.
Figure 2 – Example using 1 inch class