ENHS Nature Trails Nov 98 Article 5

The Warner Creek Burn
by Bayard McConnaughey

I attended two of the on-going Warner planning meetings as a representative from Eugene Natural History society. Large-scale catastrophes, such as the Mt. St. Helens eruption and the Warner Creek fire, offer opportunity for studies of a nature and scale impossible in normal times. Such studies including the contributions of concerned and knowledgeable citizens together with experts, if funded and carried out can add much to our understanding of forest processes and contribute to the formulation of wiser land use and management policies.

One idea being studied is to set aside part or all of the area as a Research Natural Area (RNA). Most RNA's are unique examples of habitat type, or especially rich and beautiful areas deserving protection and study as they are. This burn area is far larger than existing RNA'S (89,000 acres), and the objective would be to understand the processes involved both in the burning itself and in the changes, which occur over the years after the burn. It would be a Process RNA, the first of its kind. This is a complex undertaking.

In the first place criteria for such an area need to be developed so as to maximize the useful return in knowledge and understanding. Should it include controls such as nearby mature forest, and perhaps another burned area that has been heavily salvage-logged? How large should it be? Could the studies be satisfactorily done by study of carefully selected plots, as has been the case so far, or should the surrounding areas also be protected to minimize artificial disturbance? Some kinds of research require very large areas; others can be carried out on smaller plots, as has been done to date. The movement of fire over a varied landscape, or the subsequent changes over the years, would require very large areas, as would also studies of erosion and its effects on streams, rivers and lakes, and studies of forest regeneration over large and varied landscapes.

The intensity of the burn varied from place to place. Less intense burns destroyed the understory (herbs, shrubs and saplings) but left many larger trees alive. Somewhat more intense burns also killed larger and larger trees depending on the intensity of the burn. Where the burning was very intense the crowns of the very largest trees were also consumed. One year later snags were super abundant, but the amount of downed wood on the ground was similar to that in unburned stands, and scattered herbs and shrubs had begun to appear. Shortly after the burn large areas were seeded with rye grass (Lolium sp.) and barley (Hordeum) to control erosion. Tree seedlings, highly variable in number and spatial distribution, appeared by the second year. Areas of moderately intense burn had more seedlings than did either areas of less intense, or very intense, burns. There were also more herbs and shrubs. Tree seedlings sometimes numbered in the tens to hundreds of thousands per acre--far more than the number of trees in a mature forest. This suggests that forest regeneration will vary greatly from place to place both in both speed and nature. Some areas will be decades behind others. The processes of self-thinning in areas with great numbers of seedlings will be of interest.

Although the Forest Service will have primary responsibility, several other agencies, groups and individuals interested in succession, erosion, water quality, biological diversity, temperature changes, windfall, and other aspects of the case, would be involved.

The amount and kinds of research actually done will, of course, depend on the availability and sources of funding. It is hoped that sufficient funds can be found to support really significant research over the years and contribute to our understanding of all phases of forest dynamics.

Reference: Martin Brown, Jane Kerris and Mark Huff, 1998 The Warner Creek Burn: structure and composition of forests in the Oregon Cascades 1 to 2 years after the fire. Report to the Willamette National Forest, September 1998.

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