Silvicultural research and the evolution of forest practices in the Douglas-fir region
Curtis, Robert O.; DeBell, Dean S.; Miller, Richard E.; Newton, Michael; St. Clair, J. Bradley; Stein, William I. 2007. Silvicultural research and the evolution of forest practices in the Douglas-fir region. Gen. Tech. Rep. PNW-GTR-696. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 172 p.
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Selected excerpts:
Abstract
Silvicultural practices in the Douglas-fir region evolved through a combination of formal research, observation, and practical experience of forest managers and silviculturists, and changing economic and social factors. This process began more than a century ago and still continues. It has had a great influence on the economic well-being of the region and on the present characteristics of the region’s forests. This long history is unknown to most of the public, and much of it is unfamiliar to many natural resource specialists outside (and even within) the field of silviculture. We trace the history of how we got where we are today and the contribution of silvicultural research to the evolution of forest practices. We give special attention to the large body of information developed in the first half of the past century that is becoming increasingly unfamiliar to both operational foresters and — perhaps more importantly — to those engaged in forestry research. We also discuss some current trends in silviculture and silviculture-related research.
Introduction
Forestry is the science, art, and practice of creating, managing, using, and conserving forests and associated resources for human benefit to meet desired goals, needs, and values (Helms 1998). Silviculture is that portion of the field of forestry that deals with the knowledge and techniques used to establish and manipulate vegetation and to direct stand and tree development to create or maintain desired conditions. It is the application of knowledge of forest biology and ecology to practical forestry problems.
Modern forestry evolved over more than a century in the United States and over several centuries in Europe and elsewhere in the world. This long history is not well known to many people interested in forestry, and many natural resource professionals — including a good many foresters — know little of the scientific and social background that influenced the historical development of forestry and forest science. Yet, many modern questions and controversies are merely variations on those of the past. Any balanced consideration of current problems and possible solutions requires an understanding of how we got where we are today. …
A complete and detailed history of North American forestry and forestry research would be an enormous undertaking, far beyond our capabilities. We here confine ourselves to the much more limited subject of the development of silvicultural research and practice in the Douglas-fir region of the Pacific Northwest. In doing so, we take a broad view of silviculture, including silvics, nursery practice, seeding and planting, forest genetics, and those aspects of forest mensuration related to stand development. Our discussion will deal primarily with Douglas-fir as it occurs in western Washington and Oregon, but will also touch on important associated species. We concentrate on events and research in Washington and Oregon, only briefly touching on more or less parallel developments in adjacent Canada and California. We delve very lightly into the enormously important topic of fire and its effects. Likewise, we touch only briefly on the important role of silviculture in forest health issues such as prevention and control of root diseases, insect attacks, animal damage, and similar matters. We consciously bypass much of the large body of related work in physiology and ecology. Our main focus will be on the silvicultural research bearing on stand regeneration and stand management.
We give special attention to the period before World War II (WWII) and treat subsequent years in less detail, in part because the pre-WWII period is least familiar to the current generation of foresters. Most research in this early period was carried out by the U.S. Forest Service, the number of people involved was small, and they often worked on a variety of topics. The early researchers included some truly remarkable people who made enormous contributions. The memory of these people and their contributions should not be lost. …
Reduced Fire Frequency Changes Species Composition of a Ponderosa Pine Stand
Alan Dickman. 1978. Reduced Fire Frequency Changes Species Composition of a Ponderosa Pine Stand. Journal of Forestry, January 1978.
Full text [here]
Selected excerpts:
Abstract
In the Umpqua National Forest, Oregon, a 35-acre ponderosa pine (Pinus ponderosa Laws.) stand situated in the midst of a Douglas-fir (Pseudotsuga menziesii [Mirb.]Franco) forests is being invaded by Douglas-fir seedlings as a result of reduced fire frequency within the last 50 years. In earlier times frequent ground fires kept Douglas-fir at a minimum.
Pine Bench, an area on the Umpqua National Forest, Oregon, is undergoing a drastic change in species composition. The understory, which according to an early settler, Jessie Wright (personal communication, 1975), was open and grassy until a half-century ago, now contains thickets of Douglas-fir that are shading out seedlings of the overstory ponderosa pines. A study was made to determine the cause and extent of this shift. …
Results
The size-class distribution (fig .1) shows that among the large trees there are far more ponderosa pines than Douglas-firs, while among the small trees there are far more Douglas-firs than ponderosa pines. The age class distribution (fig. 2) shows that the change occurred rather suddenly. …
The linear regressions show that Douglas-fir grows faster than ponderosa pine on Pine Bench; Douglas-fir appearing in the same size-class is actually younger. Therefore, the difference in the large number of old ponderosa pine and the small number of old Douglas-fir is actually even greater than the size-class distribution indicates.
The shift in, species composition began, then, when the middle-aged trees were seedlings. The number of Douglas-fir germinating and surviving was relatively small and stable until 1925, but thereafter increased steadily up to the present.
Discussion
The change seems too quick and drastic to be a result of natural succession. Grazing does not seem responsible, either. According to Jessie Wright (personal communication) cattle were driven through Pine Bench from 1917 to 1952 on their way between summer and winter grazing areas. The cattle were never on the bench long, however, and their impact was slight. Furthermore, Mrs. Wright told me that they grazed fir in preference to pine.
Reduced fire frequency seems the most likely cause of the invasion. …
Two factors may have combined to reduce the frequency of fires on Pine Bench in this century. First is the absence of Indian or settler-caused fires, although as early as 1840 the number of Indians in the North Umpqua Valley was very small (Bakken 1970). An equally likely cause is the suppression of fires by the U.S. Forest Service.
By 1920, a Forest Service fire lookout was established on Illahee Rock, only four miles from Pine Bench, although it was not until the introduction of aerial fire-fighting techniques that control became highly effective. Douglas-firs living through the 1920s and 1930s would have almost been assured of survival once the more effective fire suppression of later decades began.
Prescribed burning has been proven valuable and workable in maintaining ponderosa pine stands (Weaver 1964, 1965) and should be considered for Pine Bench.
Mistreatment of the economic impacts of extreme events in the Stern Review Report on the Economics of Climate Change
Roger Pielke Jr. 2007. Mistreatment of the economic impacts of extreme events in the Stern Review Report on the Economics of Climate Change. Global Environmental Change 17 (2007) 302–310.
Roger Pielke Jr. is a Fellow of the Center for Science and Technology Policy Research, University of Colorado.
Full text [here]
Selected excerpts:
Abstract
The Stern Review on the Economics of Climate Change has focused debate on the costs and benefits of alternative courses of action on climate change. This refocusing has helped to move debate away from science of the climate system and on to issues of policy. However, a careful examination of the Stern Review’s treatment of the economics of extreme events in developed countries, such as floods and tropical cyclones, shows that the report is selective in its presentation of relevant impact studies and repeats a common error in impacts studies by confusing sensitivity analyses with projections of future impacts. The Stern Review’s treatment of extreme events is misleading because it overestimates the future costs of extreme weather events in developed countries by an order of magnitude. Because the Stern Report extends these findings globally, the overestimate propagates through the report’s estimate of future global losses. When extreme events are viewed more comprehensively the resulting perspective can be used to expand the scope of choice available to decision makers seeking to grapple with future disasters in the context of climate change. In particular, a more comprehensive analysis underscores the importance of adaptation in any comprehensive portfolio of responses to climate change.
Introduction: exploiting an excess of objectivity
In a provocative article titled “How Science Makes Environmental Controversies Worse” Daniel Sarewitz explains that scientific research results in an “excess of objectivity” in political debates (Sarewitz, 2004). What he means with this phrase is that in most (if not all) cases of political conflict involving science, available research is sufficiently diverse so as to provide a robust resource for political advocates to start with a conclusion and then selectively pick and choose among existing scientific studies to buttress their case. Simply put, to cherry pick, to take the best leave the rest. …
Using a spatially explicit ecological model to test scenarios of fire use by Native Americans: An example from the Harlem Plains, New York, NY
William T. Bean and Eric W. Sanderson. 2007. Using a spatially explicit ecological model to test scenarios of fire use by Native Americans: An example from the Harlem Plains, New York, NY. Ecological Modelling 211 (2008) pp. 301–308.
Full text [here]
Selected excerpts:
Abstract
It is unclear to what extent Native Americans in the pre-European forests of northeast North America used fire to manipulate their landscape. Conflicting historical and archaeological evidence has led authors to differing conclusions regarding the importance of fire. Ecological models provide a way to test different scenarios of historical landscape change.We applied FARSITE, a spatially explicit fire model, and linked tree mortality and successional models, to predict the landscape structure of the Harlem Plains in pre-European times under different scenarios of Native American fire use. We found that annual burning sufficed to convert the landscape to a fire-maintained grassland ecosystem, burning less often would have produced a mosaic of forest and grasslands, and even less frequent burning (on the order of once every 20 years) would not have had significant landscape level effects. These results suggest that if the Harlem Plains had been grasslands in the 16th century, they must have been intentionally created through Native American use of fire.
Introduction
The use of fire by Native Americans in northeast North America has been the subject of much debate shared among a broad group of ecologists, archaeologists and environmental historians. Some like Day (1953), Cronon (1983) and Krech (1999) believe that Native Americans used fire often to manipulate their landscape, and that these manipulations may have taken place over broad extents in the pre-European forests.
Skeptics admit that the rate of forest fires around a village might have been elevated over a background rate because Northeast Indians were using fire for cooking and pottery. However, they find little evidence that fires were widespread or intentionally set (Russell, 1983). Early settlers rarely offer first-hand accounts of fires and fewer still tell of intentional burning. These, Russell says, might be attributed to escaped fires.
Intentional burning has many potential benefits for hunting and gathering peoples: frequent fires can clear tangled vegetation, making it easier to travel through and to clear for horticulture (Lewis, 1993); fire can create vegetation mosaics that are attractive to deer and other game species, and make hunting easier (Williams, 1997); sometimes people set fires just for fun (Putz, 2003).
Of course different fire regimes have different effects on the ecology of Northeast forests. A frequent fire regime would favor a grassland with lingering oaks, a fire-tolerant genus (Swan, 1970; Abrams, 1992, 2000). Less frequent fire would lead to regenerating forests (Abrams, 1992). Understanding Native American use of fire is important for understanding the structure and function of pre-European forests.
