Final Report, Forest Restoration of Sun Creek, Crater Lake National Park
Restoration of Natural Conditions by Fire
The species composition of the pre-logging, pre-fire suppression forest can be roughly reconstructed from the age class data and the dispersion data. The relative overstory species composition (Table 3) is one goal towards which restoration efforts should strive.
The prescribed fires in unlogged areas resulted in progress towards the goal. The pre-fire suppression structure is basically intact, and the effect of fire is mainly in those diameter and height classes of white fir which have invaded since fire was eliminated from the ecosystem.
In logged areas, progress was more variable. In the ponderosa pine area, little progress was made because there was almost no pine on the plot to benefit from reduced white fir densities.
|Table 3. Reconstructed overstory species composition of the two forest types.|
On the sugar pine logged plot, some progress was made, but there was substantial sugar pine mortality in the smaller trees.
Figure 6. Map of fuel and shrub cover before “Case” is chinquapin and “Ceve” is snowbrush; the plot is the unlogged ponderosa pine plot. (left) and after (right) fire.
Much of the future progress in restoring “natural” forest structure to the Sun Creek area depends on delineation of whether plots were logged or not, and if logged, the post-logging success of pine regeneration. The next section of the report looks at stocking of the logged areas on a broader scale, so that the specific recommendations for treatments which follow can be made for each area.
It should be emphasized that the research results give a conservative estimate of the impact of the fire, because they document only first year effects. Root damage due to the fire has created additional summer moisture stress for some trees, and further mortality of some trees through Insect attack may be expected. (Ferrell, 1978, Fischer, 1980). Similarly, the environment of the tree seedling establishment has been altered, and new regeneration of pine and fir may result.