Alternative Design and Analysis - The Custodial Alternative

One popular alternative is to do nothing. This alternative may be labeled the Custodial Alternative. With no active human management activities allowed, custodial management can be used to represent one end of the spectrum of choices. In order to evaluate the consequences of the Custodial Alternative we can forecast the natural dynamics of growth and death on the Bent Creek Experimental Forest to a common point in time in this case 40 years into the future. This forecasting simulation needs to provide us with an estimate of the effects of implementing the alternative under consideration on the landscape being managed. From this analysis we will gain an understanding of the consequences inherent in the proposed alternative. FVS, a general vegetation dynamics simulation model, was used to generate the forecast for this example. (Table:Existing ecosystem management decision support software for forest conditions of the United States )The resultant simulated future forest ecosystem was then compared to the goal hierarchy using NED.

Under the Custodial Alternative (BROKEN-LINK BROKEN-LINK Table), Goal G-1 Large Scale Variety has lost ground. Although the overall rating of "Not Satisfied" has not changed, forty years from now 93% of the Bent Creek management unit will be in the Large Sawtimber size class. From the perspective of satisfying goal G-1, having 93% of the area in a single size class is definitely worse than having 76% in a single size class, which is the current situation. Goal G-2, Local Biological Diversity, has also moved further away from being satisfied. Now, the small and large sawtimber sizes together make up 99% of the forest compared to the current condition of 95%. Goal G-3, Sawtimber Production, has also declined. Under the Custodial Alternative 87% of the stands do not meet the stand DFCs, up from the current 78%. The proportion of stands that were rated "Fully Satisfied" dropped from 14% to 6% due to a reduction of the proportion of high value species as a percentage of total stand basal area. In other words, high value sawtimber species were losing the competition battle to more vigorous but lower value sawtimber species. A few stands improved their rating because their relative density increased. But overall, the Custodial Alternative moved the forest away from satisfying goal G-3. Goal G-4, Limit Peak Flow, remained unchanged because conifer species were still missing from the riparian stands.

Finally, Goal G-5, black bear, showed a marked improvement under the Custodial Alternative. The overall rating for the management unit improved from "Minimally Satisfied" to "Fully Satisfied." Due to numerous stands growing into the large sawtimber size class from the small sawtimber size class, the proportion of stands rated as "Fully Satisfied" improved from 25% to 78%. Remember, that we are assuming that all large sawtimber sized stands provide more than the required 3.5 m³/ha of coarse woody debris while small sawtimber sized stands do not. One could certainly argue that the desired conditions for black bear ought to be modified so that mast production is more than a presence/absence metric. One would expect a large sawtimber sized oak stand to produce significantly more acorns than a small sawtimber oak stand. But the BROKEN-LINK BROKEN-LINK closed world assumption forces us to ignore such considerations because they are not considered in the DFCs as currently defined. The goal hierarchy can be changed at any time by the decision makers, stakeholders, and domain experts to create a new "closed world assumption" if the present one needs improvement.

In summary, the homogeneous large sawtimber management unit created by the Custodial Alternative is less successful than the current condition in satisfying goals G-1, G-2, and G-3. It improves the rating of goal G-5 compared to the current condition and is neutral with regard to goal G-4.

Several important points should be noted. First, these analyses are clear and understandable. Each goal can readily be compared to the current conditions and any hypothesized alternative. Some goals such as goals G-1, G-2, and G-3 move in concert with each other. Some goals, such as G-5, move in the opposite direction. Some goals, such as G-4, are neutral with respect to some kinds of changes in the forest ecosystem. Furthermore, it is easy to recognize which goals have which tendencies. Those goals that tend to move in concert over a wide variety of ecosystem state changes can be thought of as generally compatible with each other. Those which frequently move in opposite directions can be thought of as generally incompatible with each other. One byproduct of this process is therefore a clear and objective way to identify goal compatibility, neutrality, or conflict.