What’s the best way to create environmental stewards? I think about this frequently, and more as the last week has dragged on. One of the goals of Pikes/Pines is to instill a sense of place. As we continue to urbanize in a global world, we can lose sight of place, a sense of belonging and caring for natural landscapes. I don’t blame people who moved here recently for not knowing much about our native flora and fauna, but they’re not off the hook. Will learning a couple native plants help a transplant care more about the place they live, or make them vote for the environment? I’d like to think so. Thus, I introduce, or re-introduce, four common, native trees that you can find on Capitol Hill.
Black Cottonwood (Populus trichocarpa) – We know forestry is big in the Pacific Northwest, but you probably didn’t know the first tree to have its genome sequenced was a black cottonwood. An unassuming female, Nisqually-1, named for the river where she is rooted, was sampled and sequenced in 2006. Black cottonwoods were chosen for this honor because they are economically important trees (mainly for lumber) and fast growing, both which make them an ideal model species for research.
I enjoy their many towering spires, thrust up from a river bank among dense clusters of alders and willows. They are called cottonwoods, not because they make cotton, but because their seeds are distributed within a gauzy little ball that resembles cotton and floats readily on the wind or water. Unlike many of our native trees, cottonwoods are typically dioecious. Female and male catkins (reproductive bodies) are typically borne on separate trees (read: male and female trees).
Large cottonwoods are prone to failure as they age, dropping tremendous limbs, and making them less than ideal neighbors. You can still reliably find them growing in the St. Marks Greenbelt and down in the watery reaches of the arboretum.
Western Redcedar (Thuja plicata) – If you grew up in Seattle and participated in any sort of environmental education, you’ve heard about the Western redcedar, or the tree of life. This was the tree for the indigenous people of our region. Giant cedars that took days to fell became dugout canoes for hunting forays. Cedar bark was taken in giant strips and
turned into cordage, for netting birds and fish, and clothing, from rain-shedding cloaks to smooth baby diapers.
Enthnobotancial significance aside, a mature tree is the definition of venerable; I’m talking 200 feet tall venerable, and 1000 years old venerable. Their huge buttressed roots support
a bulging trunk that twists up into drooping limbs covered in scaly green foliage. They are partially shade tolerant and enjoy moisture, a good suite of talents when you’ve got massive Douglas fir and Western hemlock to contend with.
Look for them in patches of Interlaken Park or just around the Hill. They’re common. People have planted related species, but none that get quite so large or have quite so red a bark.
Red Alder (Alnus rubra) – I remember watching a Pileated Woodpecker chunk off large sections of alder bark as a teenager, realizing where this tree got its name. Outwardly unapparent, beneath outer bark is a brilliant rusty red. The wood itself well known for use in smoking salmon, and the bark makes an excellent russet dye.
An arborist friend of mine called red alders trash trees. To a logger, these were the trees that (temporarily) out-competed more valuable timber on logged land. Little did they know that as the first trees to grow back after logging, fire, or other disasters clear the landscape, alders help in restoration. They are nitrogen fixers, adding lost nutrients to poor soils and rebuilding landscapes robbed of life. I appreciate their serrate leaves, the gentle shade of their canopies, and their propensity for developing soft spots and cavities, inviting all sorts of wildlife looking for food and shelter. They aren’t trash.
Alders will grow happily in our greenbelts and like the wet. They’re common by the lake in the arboretum, and in many other forgotten corners of the Hill.
Western Hemlock (Tsuga heterophylla) – If you could time travel to the Hill before European explorers, I am willing to bet a predominant feature would have been giant trees, mostly Western hemlocks. This is our temperate rainforest climax species, waiting in the shade for Douglas firs to get old and topple over. They also get exceptionally large, coming in close the 300 feet tall in the extreme. The Western hemlock is also our state tree, representing those of us on the wet side well, but less so for the dry side.
Western hemlock needles are different lengths, which their species name. hetero, as in heterogeneous, and phylla, as in leaf, denotes. Lots of trees in our native forests grow on nurse logs or stumps (a decaying log that serves as a natural planter), but none quite so often as the hemlock. They will often surround a stump with roots, and are left on stilts when the nurse material melts away over time.
Look around for their droopy top and you’ll soon see Western hemlocks here and there on the Hill. They are most common in shadier, damp hillsides and won’t seed well in the bright sunlight. I sound like a broken record, but Interlaken Park will show you a few nice specimens.