by Christy Solo – Editor
As spring leaves continue to unfurl, the week we’ll explore four of Oregon’s deciduous trees.
We had a lot to choose from, so we’ll have to explore more at a later date, but for this week we chose Red Alder, Oregon Ash, Quaking Aspen and Vine Maple.
Red alder (Alnus rubra) is the largest species of alder in North America and one of the largest in the world. Luckily for us it’s a West Coast exclusive tree growing only from Central California up through British Columbia.
Why is it called “red” (rubra) alder? The inner bark of these trees is red-orange, so if the tree is wounded (bark peeled off) the wound turns red. We can only suppose someone thought “bleeding alder” was a bit too goth for a common name.
There are a couple of things red alders love: water and disturbed areas. You’ll find a lot of them in riparian areas, but they also love to fill in a burned or otherwise recently disturbed area.
Red alders produce a lot of seeds so you can find several hundred thousand to several million seedlings per hectare in the first year after a disturbance. This is really impressive considering how much our small area songbirds, such as American and lesser goldfinch as well as pine siskins love to chow down on alder seeds. They still leave enough for new groves to grow.
Red alders are a “live fast and die young” tree. Well “young” in comparison to our hundreds-of-years-old conifers. The alders grow quickly and live 40 to 60 years.
Fun fact: When alders sprout up in disturbed areas, they are quite beneficial. Not only do they quickly provide new habitat for many species of animals, but they help stabilize the soil and prevent erosion. But wait, there’s more! They also restore nutrients to the soil because red alders have a symbiotic relationship with the nitrogen fixing bacteria Frankia.
Fun fact: Even though red alder is often found in riparian areas, it isn’t a fave food of beavers so if grown in your yard, they’ll probably leave it alone. However, deer and elk will browse red alder’s twigs and buds.
Final fun facts: Red alder bark can be boiled to create a russet-colored dye. Indigenous peoples also used the bark to treat poison oak reactions, insect bites, skin irritations and even open wounds.
Next up, the Oregon ash (Fraxinus latifolia). We know we aren’t even halfway through our four trees, but we must say that the Oregon ash is pretty much the perfect tree. The only drawback is it isn’t a tree for “every yard” as the Oregon ash is very nearly totally restricted to riparian areas.
If you have an area in your yard that regularly floods, or a rain garden, you can plant an Oregon ash.
What makes this tree so amazing? It’s great for soils, it stabilizes them and filters out pollutants. It’s extra, super great for wildlife. It provides habitat and meals for birds, native bees, aquatic insects, small mammals and aquatic mammals. Additionally it is the support tree for dozens of species of butterflies and moths. Ash are also easy to grow.
While persnickety about water, the aren’t as picky about soil type, they like clay or silty clay but will do well in sandy, rocky and gravelly soils. Full sun is their first choice, but they will also thrive in partial sun.
As with red alder, Oregon ash are a west coast tree growing only in Oregon, California and Washington. Once again, lucky us!
Oregon ash have nifty lance-shaped leaves which provide lots of cover and shade, but their flowers and fruits are arguably even more interesting! Flowers on male ash grow in chunky little clusters near the tips of branches, looking more like some weird vegetable than a flower. Female flowers bloom in little sprays, also near the end of branches.
The fruits (AKA seed pods) grow on the female trees in elegant clusters. The fruits are samaras – meaning the seeds have “wings” like maple fruits (though ash only have one wing) which help them disperse via wind.
Fun fact: Oregon ash trees grow to between 60 and 80 feet, and they grow fast initially. They can spring up to 10 feet in 10 years before slowing down to a marathon pace for their final feet.
On to quaking aspen (Populus tremuloides).
Fun fact: Quaking aspens are the most widespread tree in North America. They grow from the Midwest, across Canada, north into Alaska and across the West through to Arizona and New Mexico.
In Oregon they are only found on and along the Cascades, so once again “lucky us!”
We feel we’d be remiss if we didn’t start off our discussion on quaking aspen by pointing out, they are just flat-out stunning trees. They absolutely glow in autumn, basically trees full of treasure with their coin-sized and shaped golden leaves. Bare stands in winter evoke a positively faerie tale vibe.
Next we need to mention we really shouldn’t refer to quaking aspen in a plural sense, because each grove of quaking aspen”s” is one big organism. They spread through underground roots with new trunks growing up from those roots. So, every tree in a stand may have the same genetics!
Fun fact: Before any aspen trunk appears above the surface, the root system may lie dormant for many years until the conditions are just right for growth.
We’ll pause here to point out you can still purchase a single quaking aspen tree for your yard, however if you don’t want a grove, you’ll need to keep an eye on sprouts (but, who wouldn’t want a grove?) Quaking aspen grow even faster than ash, they sprout up a whopping 24 inches per year. They’ll max out between 40 and 50 feet.
Fun fact: Quaking aspen come back fast after a fire. When one tree is damaged – from fire, disease or even insects – it will come back quickly from the roots. But wait! There’s more! The damaged tree will release stress hormones telling the grove as a whole “We’d better get growing!” This will cause other buds within the root organism to start growing into trees.
Quaking aspen are also a wildlife favorite. Because they grow so quickly they are one of the softest hardwood trees. This makes them great for woodpecker species such as flickers and sapsuckers to nest in, easy nest excavating. They also produce lots of sugars attracting elk and deer. The leaves are soft and tasty too and more nutritious than those of many other trees. This attracts insects which attract even more birds.
Final fun fact: Quaking aspen got their “quaking” moniker from the sight and lovely sound their small leaves make when “quaking” in a breeze.
Last but not least is the vine maple (Acer circinatum). Vine maples are our third strictly West Coast tree, growing only in Oregon, California, Washington and a bit into British Columbia.
In Oregon they grow only between the Coast and the Cascades.
In addition to being peak PNW trees, vine maples are quirky trees. They are an understory tree, which means they can thrive in the shade. They got their “vine” common name for their propensity to grow every which way and sometimes even up.
A single vine maple is usually a formed by several trunks which are often tightly wound or clumped together at the base of the tree before each spreads out. Vine maples which get more sun can grow to 30 feet in height and 20 feet across.
Vine maples grow two ways, either new growth coming up from the roots (like quaking aspen!) or from seed. Because they can do the “clone grow” thing they are another tree that can quickly populate a burned area helping the soils and wildlife.
Vine maples also have flowers and seeds. The flowers grow in clustered sprays and the seeds (fruits, samaras) are the classic maple double-winged samaras.
Fun fact: Squirrels and chipmunks love vine maple seeds and often cache them. The do need to compete with various birds for those delicious seeds though, such as nuthatches, chickadees, grosbeaks, warblers, waxwings, vireos and woodpeckers.
Birds, mammals and pollinators use the flowers for food, helping those flowers to become fruits.
In addition to being another “right out of the pages of a faerie tale” trees, vine maples make excellent landscape trees.
They prefer shady, moist areas but will grow in sun. Really, finding a beautiful landscape tree that loves shade is a wonderful way to create layers in your garden. Vine maples are so nifty they are considered to be the most useful native tree for the landscape in the PNW.
Final fun fact: Vine maple branches are so supple and “viney” Indigenous peoples used them for weaving.
