CHAPTER 1
Unlocking Douglas-Fir’s Secrets
Douglas-fir is an enigma. Its mix of distinctive structural features and physiological attributes produces a tree that is puzzling, exceptional, and in ways a marvel of nature. World class in height, geographic distribution, and wood quality, and unique in architecture and genetic composition, Douglas-fir also acquires nitrogen in novel ways, and at times even irrigates itself. Though this tree has long played an integral role in the lives of humans and animals, many of its secrets are only now being understood through modern science.
Two geographic varieties are recognized, though they exhibit only subtle physical differences. The taller, faster-growing of the two varieties, coastal Douglas-fir (Pseudotsuga menziesii variety menziesii), occupies the Cascades, Sierra Nevada, and the British Columbia Coast Range, and extends westward to the Pacific shore. Regions to the east are inhabited by the typically shorter inland, or Rocky Mountain, Douglas-fir (P. menziesii var. glauca), which grows slower and is more cold-tolerant. There are, of course, exceptions. Some habitats within the coastal distribution—such as bedrock sites in the droughty San Juan Islands—support short, limby coastal Douglas-firs, while inland Douglas-firs in moist, wind-sheltered canyons and ravines often grow straight and very tall with little taper.
Because of its much greater size and hence commercial value, the preponderance of scientific inquiry has focused on the coastal rather than inland variety of Douglas-fir. The descriptions, taxonomic difficulties, potential maximum sizes, and water and nitrogen relationships presented here pertain to coastal Douglas-fir unless otherwise noted.
The tree’s botanical identity confounded science for more than a century after naturalists first described it—even though its wood was already serving as the world’s preferred construction lumber. Douglas-fir was known by more than a dozen common names in the nineteenth century before an official name was finally agreed upon. Selecting a scientific name proved even more elusive. Much drama played out first, and many botanists’ dreams of naming the tree were dashed before an acceptable name was found.
Archibald Menzies, a botanist and surgeon who served as naturalist on an early British voyage to the Pacific Northwest, first collected a specimen of Douglas-fir twigs and needles (but no cones) on Vancouver Island in 1791. Menzies did not describe the tree in his journal at the time because he changed jobs when the ship’s surgeon fell ill, but Meriwether Lewis described Douglas-fir on his return trip up the Columbia River in 1806. Lewis referred to the specimen he collected as Fir No. 5, which included a written description of the foliage and cones and a drawing of the distinctive cone bract.
David Douglas, the botanist whose name would eventually be adopted for the tree’s common name, first arrived in America from Scotland in 1823. The prestige of his association with the Royal Horticultural Society of London opened doors to the finest botanists in the United States, and Douglas made good use of his enhanced access. The timing of his arrival could not have been better. In 1824 the Hudson’s Bay Company announced their plans to sponsor a plant collector along the Columbia River, and the young, welltrained Douglas was the natural choice. As a final step in getting ready for his new job in the Pacific Northwest, Douglas arranged to meet Archibald Menzies in London with high hopes of gathering some last-minute advice. When the two men met in the spring of 1824 for a chat over tea, little could they have imagined the role their names would play in the drawn-out process of selecting both a common and a scientific name for Douglas-fir.
Although still early in his career, the energetic and outgoing Douglas had quickly made a name for himself through his association with the Royal Horticultural Society and Hudson’s Bay Company, and his acquaintance with many big-name botanists of the time. On his first sponsored trip to the Pacific Northwest from 1824 to 1827, Douglas diligently collected specimens and seeds (including 120 pounds of Douglas-fir seed, equivalent to about three million seeds) from hundreds of plants and trees for later study, classification, and planting back home. His plant collection set a record for the number of species introduced by an individual into England, the leading country in botanical research at the time. Upon his return to London in the fall of 1827, Douglas was welcomed home as a celebrity. The prodigious amount of seeds that he sent or carried back to the Horticultural Society in London overwhelmed the capacity of their gardens for planting, requiring them to engage the help of private nurseries. Douglas-fir seedlings resulting from these efforts were widely distributed to public and private gardens across the United Kingdom. Some of the trees remaining from those early plantings now soar more than 200 feet tall; serendipitously, one such giant grows near Douglas’s birthplace in Scone, Scotland.
Given Douglas’s celebrity, it is not surprising that in 1833 the English publication Penny Cyclopaedia used the name “Douglas Fir” in its description of the species, honoring and acknowledging Douglas as the discoverer “of this gigantic species . . . found in immense forests in North-West America.” The Penny Cyclopaedia was a companion publication of the Penny Magazine, a weekly magazine that sold for a penny to make it widely available to the general public. Both publications were put out by the Society for the Diffusion of Useful Knowledge, whose altruistic intent was to educate the working class in Britain. The newly proposed name gained traction in Europe but became just one among many other names used in North America in the 1800s.
In 1909 the US Forest Service officially accepted “Douglas fir” as the agency’s preferred common name for the tree after a census of western lumbermen found that it was used more than all other names combined. But the search for a universally acceptable common name continued. Coastal loggers favored the name “red fir” because of the tree’s reddish heartwood, and many other names were also in use. As late as 1939, Yosemite naturalist James Cole observed, “These magnificent trees from the Northwest are somewhat of a botanical puzzle as indicated by their 28 common names.”
Given the hodgepodge of names for this tree that changed over time and place, difficulty in settling on “Douglas-fir” as the official common name is understandable. It wasn’t until 1950 that the hyphenated version of the name was formally adopted by the Seventh International Botanical Congress in Stockholm. Even today “Douglas fir”—two words—is more often used in the popular media (including in the title of this book) instead of the correct form, “Douglas-fir,” which implies that this distinctive tree is not actually a fir. James Reveal, an expert on the drawn-out process of naming Douglas-fir, found it ironic that the final choice perpetuated a twopart name that is incorrect on both sides of the hyphen. Reveal wryly noted that “This tree is not Douglas’s,” because someone else first described it scientifically, “and it is not a fir,” because the tree’s characteristics—such as hanging rather than upright cones and pointed rather than rounded buds—clearly fall outside the description of true firs.
Finding an acceptable scientific (Latin) name for the genus and species of Douglas-fir was even more challenging. Foliage collected by Menzies on Vancouver Island in 1791, plant collections and descriptions made by Lewis in 1806 along the Columbia, and plant materials collected by Douglas on his trips to the Northwest between 1824 and 1830 provided the basis for eighteen scientific names proposed for this species before a suitable name was found. No other North American conifer even comes close to Douglas-fir in terms of how many names were proposed and rejected before authorities agreed upon a valid name.
The quest began in 1803 when a British botanist named Lambert submitted the first Latin name for Douglas-fir, Pinus taxifolia, based on Menzies’s sample collected in 1791. The submission was rejected because the name had already been assigned to an entirely different conifer. Seventeen additional scientific names would be submitted over the next 150 years, sixteen of which were deemed invalid because the name had either already been used or did not meet international taxonomic rules. During this period, trees were found in the mountains of Southern California, Japan, and remote reaches of China that shared similarly distinctive cones
