by Theodore Hoss
Stepping into the forests of Whatcom County usually means entering a world of green. Douglas-fir and western red cedar cast verdant shadows on a forest floor covered by mosses, western sword fern, twin flower, salal, Oregon grape, and trailing blackberry. In general, the Salish Sea territory is an excellent place to be a plant.
Cool wet winters provide ample moisture for growth without an excessive risk of freezing. Warm summers offer a nice, comfortable growing season without too many days of scorching heat, and well-drained, nutrient-rich soils support a world that, at first glance, seems like nature in its most abundant form. However, take a closer look and it quickly becomes apparent that this wall of green is composed almost entirely of just a few dozen plant species. Douglas-fir dominates for miles around; the sword fern and salal grow so thick that ground cover plants find difficulty establishing beneath them.
Another Type of Habitat: “Balds”
These evergreen forest habitats are the quintessential plant community of our local ecosystems. However, there is another type of habitat hidden amongst these forests whose contributions to our region’s biodiversity are truly a cut above the rest.
One of the most incredibly diverse and fascinating habitats that can be found in our region is referred to rather anticlimactically as a “bald habitat” or simply “balds.” Although their name implies a landscape completely devoid of vegetation, balds are home to a plethora of plant species. They simply lack the large trees that define so much of the rest of the landscape.
Bald habitat type occurs mainly in rocky areas where soil is thin and sunlight exposure is high. This limited soil depth and potential for higher evaporation rates creates growing conditions that are too arid to support the growth of most of the tree and shrub species common to the Pacific Northwest, thus leaving the sites open to a wide array of shade intolerant plant species which take advantage of the sunny growing conditions. Such a lack of dominant evergreen trees makes for growing conditions that appear similar to those found in Puget Lowland Prairies.
However, unlike prairie habitats, which occupy flat spaces with deep soils, balds are found on mountain slopes and coastal headlands. Additionally, balds occur primarily in small patches, sometimes less than an acre in size, scattered broadly around the region. Prairies of the Salish Sea have historically covered huge expanses, ranging from over 100 to over 1,000 acres.
Conifers Aren’t Dominant
Balds also differ from prairie ecosystems by the manner in which large coniferous trees are stopped from becoming dominant. Prairies around the Salish Sea have primarily been maintained by Indigenous fire management practices and cultural burns. Although fire can play a role in keeping balds open and sunny, the primary reason they lack large trees is due to conditions being too arid during the summer months for larger plant species to take hold. Even if trees do get established during periods of relatively wet weather, they often succumb to drought during an especially warm or dry season.
Since the environmental conditions that lead to the establishment of a bald habitat are relatively rare, these ecosystems and their associated plant communities cover less than 1 percent of the total land area of Whatcom County. However, in spite of their relatively small range, balds are absolutely critical to the conservation of many local species.
Bald habitats in Whatcom County support over 320 different species of plants. Even more significant is the fact that the majority of these species are rarely found growing anywhere outside of the small boundaries of this special ecosystem. Even in nearby spaces artificially opened by burning and clear cutting, plant diversity is usually significantly lower than that found in the adjacent bald habitats.
Taking advantage of the diverse array of plants, 80 bird varieties, at least four species of reptiles, three types of amphibians, and numerous mammals, and 70 species of fungi and lichens also make use of these rare plant communities. Dozens of insects and arachnids also make use of balds, with butterflies being particularly dependent on myriad flowering species. Animals play an important role in the lives of the plants living in these communities.
Deer, bear, and numerous smaller mammals browse vegetation, dig for roots, and expose patches of soil that allow for annual species a chance to establish. The Olympic onion (Allium crenulatum) seems to be particularly attractive to many digging species, who turn over the thin soil to pursue the fragrant and flavorful bulbs.
Oregon White Oak
Our own human species is not excluded from the list of animals who make balds a part of life! The Indigenous nations of our region have long harvested a multitude of plant species growing in these diverse habitats for food, medicine, and materials. One of the few trees common in these dry, thin-soiled conditions is the Oregon white oak (Quercus garryana), which happens to be the source of highly fatty and nutrient dense acorns.
Balds are also favored by people due to their open form, offering a chance to catch some of the limited winter sunlight that is so often lost in the tall conifers during our gray season. Many people who have hiked trails along our local coastline have likely found themselves in bald habitats without even realizing it. The incredible diversity of wildflowers in these habitats and their associated pollinators can draw great attention, pulling in people who enjoy the wide array of bright springtime colors.
Visiting a bald is truly a wonderful experience. The wide array of plant and animal life in these special places serve as a great way to learn about the wide array of life around us. While they are a marvelous place to visit, we must exercise caution to ensure that we do not inadvertently harm these fragile ecosystems with our enthusiasm for them.
Due to their thin soils and high concentration of rare plant species, balds can be particularly susceptible to trampling, especially in areas visited by large numbers of people. Exercising care to stay on existing trails can help ensure that these habitats and the species within them can continue to persist into the future. The next time you are spending some time out in the great outdoors of Whatcom County, be sure keep an eye out for the balds and their incredible diversity of species, and remember how this small ecosystem came to be and how it connects our species to the rest of the natural world.
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Theodore Hoss is an environmental educator at the Raven’s Roots Naturalist School. An alum of the University of Washington and Oregon State University, he has a background in environmental science, biology, and natural resource management. In his free time, he loves hiking, kayaking, printmaking, and finding new plant friends!
