Subalpine meadows of Mount Rainier National Park (MORA) are by far the most frequented areas of the park. Visitors are drawn by the astounding array of wildflowers and the breathtaking views of the mountain. As a result of their popularity, many of the park’s subalpine meadows have been severely degraded over the past 100 years, mainly from off-trail hiking and camping that leads to the trampling of vegetation and hillslope erosion. Since the 1980s, restoration efforts (most notably in the Paradise meadows area) have repaired much of the damage, and efforts to preserve the park’s lesser-disturbed subalpine meadows have been at least partially successful at preventing further damage. Today, however, a very different phenomenon threatens the future of MORA’s subalpine meadows; tree encroachment. It is clear from historical photos that during the last century, trees (primarily subalpine fir [Abies lasiocarpa]) have gradually migrated upslope into subalpine meadows. The underlying cause of this encroachment, however, remains unclear.
The lack of 20th century fires in subalpine meadows may be to blame for tree encroachment into subalpine meadows. Periodic fire is needed to curb seedling establishment in meadows and prevent treeline (the upper elevation at which trees grow) movement upslope. As the result of 20th century fire suppression, fire has been all but excluded from MORA since its establishment in 1899, including fire in the park’s meadows. The frequency and intensity of pre-historic fires in subalpine meadows is generally unknown, and perhaps more importantly, it remains unclear whether lightning or human-set fires were the primary source of fire ignitions in the park’s subalpine meadows prior to Euro-American settlement.
It is now widely accepted that humans have inhabited the PNW for the last 13,000 years, if not longer. Recent archaeological efforts in MORA show that Native Americans were living in the area as early as 9500 years before present, and the findings suggest intensive use of subalpine and alpine areas for resource extraction (i.e., hunting, berry gathering). Numerous ethnographic and ecological studies from MORA and similar areas of the Pacific Northwest discuss the use of fire in subalpine meadows by Native Americans as a way to increase berry harvests, herd game, improve hunting visibility, and clear frequently used trails. With the decline of Native American populations due to disease and displacement in the early to mid-1800s, and the success of fire suppression efforts in the Pacific Northwest starting ca. AD 1900, the loss of frequent and intentionally-set fires in MORA may have been the impetus for tree establishment in subalpine meadows. Many researchers are now exploring the idea that Native Americans were the primary ignition source for fire in the Pacific Northwest prior to Euro-American settlement, not only in subalpine meadows, but also in many other lower-elevation ecosystems.