Ash Phloem
Reduction Model Examples
Version 1.1
Tara L.
Eberhart, Andrew J. Storer, Linda M. Nagel
Examples of Data Entry
The
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
% Surface
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
Trees per
Figure 4 – Example using 1 inch
class
Figure 5 – Examples using 1 inch
class for large tree retention