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Douglas Fir. Stephen F. Arno
Читать онлайн.Название Douglas Fir
Год выпуска 0
isbn 9781680512007
Автор произведения Stephen F. Arno
Жанр Биология
Издательство Ingram
Finding a safe crossing of this abyss was nearly impossible. We faced the probability that a search party would be called out at dawn and that we would have to backtrack several thousand feet up the steep, brushy slopes with full packs to regain the ridgetop, find the correct route, and then descend to our intended river crossing. Worse yet, there wasn’t even a semi-flat spot for an overnight bivouac. Praying for a miracle, I climbed around a corner in the gorge and beheld an unbelievable sight: a 4-foot-thick Douglas-fir growing out of the cliffs had uprooted and lay level straight across the chasm. We had never so appreciated a tree.
In the summer of 1962, I worked at a log-scaling station in the North Cascades. Log trucks brought in huge virgin Douglas-firs from the surrounding forest. Occasionally a truck’s 30-ton load consisted of just three massive logs from a single tree, even though these giants had been harvested from steep, rocky mountainsides. Large granite boulders were sometimes jammed into a big log, testifying to the cliffs it had crashed down from. One day a log truck driver let me ride with him up to the logging site carved into granite cliffs. Big Douglas-firs grew wherever there was a patch of soil. Even as an energetic and agile young man, I couldn’t imagine how the fallers climbed those treacherous heights with big chain saws and worked there for many hours each day. The guys who measured, limbed, and bucked the logs into the lengths specified by the sawmills didn’t have it easy either. Logging in steep terrain was obviously dangerous business.
Later, as a seasonal naturalist in Olympic National Park, I studied some of the gigantic Douglas-firs scattered amid the Hoh River Rain Forest. South of the Hoh, I waded the Queets River to see the famous Queets Fir, which at more than 14 feet in diameter was the largest known Douglas-fir at that time.
The rain forest Douglas-firs were obviously ancient relicts gradually being replaced by younger western hemlock and Sitka spruce trees. I observed the aftermath of a few twentieth-century wildfires that had escaped suppression in the park’s mountain forests and saw that many big old Douglas-firs, with their thick, corky bark and lofty crowns, had survived, while associated hemlocks had nearly all died. Also, I noticed that the burned forests had regenerated young trees, especially Douglas-firs, and a rich assortment of fruit-bearing shrubs and herbaceous plants. These post-fire communities teemed with a variety of birds, some of which feed on Douglas-fir seeds, and other wildlife, including black bears, which like to strip and eat the inner bark of young Douglas-firs.
I moved to the inland Northwest in 1963 and then to the Northern Rockies for college and a career in forestry. Forests in these regions were often dominated by other long-lived trees, particularly ponderosa pine, western larch, and western white pine, each with its own unique majesty. Interestingly, inland Douglas-fir nearly always grew in these forests and often regenerated in abundance, filling the understory with saplings and young pole-size trees. Douglas-fir was clearly poised to dominate much of the inland forest.
In 1971, soon after completing a PhD in forest ecology, and keeping mum about that to coworkers in my first job in a sawmill and my second job as a timber-sale forester, I was blessed to be chosen as part of a small research team whose goal was to document examples of the original forest types in the Northern Rockies. We inventoried all trees and flowering plants in 1482 large plots within mature forest stands in Montana and described ecological conditions such as soils, geology, wildlife use, and evidence of past fires. It turned out that Douglas-fir occupied 998 of these stands—a far higher frequency than any other tree or plant. A similar inventory of forests in central Idaho accumulated a sample of 761 stands, 506 of which contained Douglas-fir, again the most frequently recorded plant. Douglas-fir is also widely present and often a dominant tree in forests from central British Columbia to central California and south through the Rockies to the high mountains of southern Arizona. And in all of these regions this species is often one of the biggest trees.
For many years I studied the fire history of old-growth Rocky Mountain forests, consisting of ponderosa pine, Douglas-fir, and western larch. For many centuries, at least, frequent surface fires prevented the highly competitive Douglas-fir from gaining dominance by killing its saplings in far greater numbers than those of fire-resistant ponderosa pine and larch.
I also examined high mountain grasslands and adjacent dry forests dominated by Douglas-fir and lodgepole pine, including the 6500-foot Lamar Valley in Yellowstone National Park. This high, dry grassland environment with its relatively light snowfall serves as critical winter range for the area's elk, deer, and bison, and attracts predators and scavengers such as wolves, ravens, and eagles. Historically, frequent grass fires kept the surrounding forest at bay. Older Douglas-firs tend to be fire-resistant, and some trees at the edge of what used to be an open forest were four or five centuries old and had survived many fires. A few of them measured 4 to 5.5 feet in diameter. But starting early in the twentieth century, two factors allowed Douglas-fir saplings to colonize the Lamar Valley grasslands: fire suppression, and heavy grazing by a burgeoning elk herd that resulted from exterminating the elks’ primary native predator—wolves. Nearly a century later, despite the sparse grass fuel, the 1988 Yellowstone fires burned the surrounding and encroaching Douglas-fir forest more severely than most historic fires because of the accumulation of young Douglas-fir thickets and fallen tree limbs and snags.
After sixty years of observing both coastal and inland Douglas-fir and studying their ecology and historical importance, I feel passionate about sharing the story of this truly extraordinary tree. Books and scientific publications have not done full justice to the enormous role the two varieties of Douglas-fir have played in the lives of humans since first contact, nor to the trees’ preeminent stature and influence in western forests.
I(Carl) had a distinctly different introduction to Douglas-fir. My experiences started later in life, in a different place, and with the inland rather than the coastal variety. My interactions and perceptions relative to Douglas-fir also differ, but together our perspectives provide a broader and more nuanced story of this enigmatic western tree. Much like two blindfolded men grabbing the opposite ends of an elephant, our initial perceptions reflect our contact with an “elephant” in the plant kingdom that is so widely distributed and variable that it is better described and understood from more than one angle.
My first encounter with Douglas-fir didn’t come until I moved west for college, because it isn’t native to the Northwoods of Wisconsin where I grew up. I arrived at the University of Montana on a fall afternoon in 1967, hurried over to Main Hall to skim the job listings, and promptly landed part-time surveying work. I started my new job the next morning, and as an inquisitive newcomer, I queried my boss about the unfamiliar trees I saw along our drive to work. I felt somewhat betrayed when he identified several unimposing trees with gray bark and dark green needles as Douglas-firs. I had grown up seeing eye-catching Weyerhaeuser ads of coastal Douglas-fir forests in the 1950s, and frankly these trees didn’t measure up. Naively assuming that all Douglas-firs were the large kind, I was unaware of the smaller Rocky Mountain variety. I would later learn that despite their typically modest presence, inland Douglas-fir comprise an ecological time bomb across much of the Mountain West. Over the next fifty years, my work and travels along the backroads of the West would allow me to experience Douglas-fir in two Canadian provinces, eleven western states, Texas, and in virtually all of its native habitats. Seeing the species in its countless manifestations led me to conclude that Douglas-fir is truly the Jekyll and Hyde of the western forest, depending on the time, place, and variety (coastal or inland).
I was drafted by the Army in the summer of 1970 and sent to boot camp at Fort Lewis (now Joint Base Lewis-McChord), about 50 miles south of Seattle. While out on maneuvers one day, I was shocked to see the tops of scattered mature ponderosa pines poking above smaller coastal Douglas-fir. My dismay came from seeing ponderosa pine growing just off the shores of Puget Sound, where it seemingly didn’t belong. The much greater precipitation and higher humidity that characterized