‘Tis the season for fragrant evergreens. Fresh, woody, crisp, sharp or earthy–evergreen trees and boughs bring olfactory bliss to anyone who dares take a sniff. Each conifer has its own unique smell derived from chemical compounds in their needles and bark. Collectively these chemicals are called terpenes (based on 5-carbon units known as isoprenes) and are usually produced as part of the tree’s defense mechanism–warding off potential pests and disease–among a range of other functions. For humans, however, there is mounting evidence that forest scents may also have many potential therapeutic benefits; making a walk in the forest (a.k.a. forest bathing), just that much more appealing
As for me, the health benefits of terpenes is– like the frost on a cold winter morning– a welcome bonus! Thus, this winter I have set out to not only visually observe the many different species of conifer in my local forests, but smell them–crushing needles all the way. Today, I give you my findings thus far:
Douglas-fir
Douglas-fir can be identified by its soft, flat, 1-1.5 inch needles that spiral around each branch with two white bloom lines on the underside. When pinched or crushed, Douglas-fir needles have a mild sweet lemon and woody scent. Look for their distinct cones pointing downward with three-pronged bracts that stick out from beneath each scale or their dark pointed buds to help confirm identification.
Western redcedar
Tiny, flat-scale like leaves, often with a butterfly shaped bloom on the underside, arrange onto droopy sprays of foliage that fall opposite each other on each branch. This moisture-loving conifer’s leaves are delightfully sugary-sweet smelling with perhaps a hint of pineapple or pear. If you are lucky, you may find some of its rose-bud shaped cones hanging in clusters from the branches.
Western hemlock
Short, flat soft needles of variable length (no longer than ¾ an inch), arrange themselves irregularly around each branch, creating what I like to call the “bedhead” effect. This shade-tolerant conifer’s needles smell faintly like grapefruit when crushed. On a nice day, watch the sunrays scatter through the hemlock canopy; look up and find its drooping leader–a telltale hemlock trait.
Ponderosa pine
Very long, fairly stiff needles (5-10 inches) grow from the ponderosa in bundles of three. When crushed these needles smell woody and sharp, like turpentine (unsurprisingly). Notice the thick puzzle-piece shaped bark of the ponderosa pine–a helpful adaptation to low-intensity fire. If you find a mature tree, take a whiff of the bark, as well, as it is known to give off a sweet vanilla or caramel scent, especially when warmed by the sun.
Grand fir
Two-ranked shiny, dark green needles, with two-white stomatal bands below, splay out like the keys of a grand piano. As for the smell, well this one is a favorite–warm and citrusy, like tangerines. Their stiff branches give the grand fir a stately more structural appearance, similar to other firs, with cones that face upwards high in the branches.
So, go on a walk in your local forest and bask in the many sights and smells it offers. Enjoy the complexity that nature offers as you roam. Stop and smell an evergreen.
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Curious about coastal conifers? Want to tell them apart? You are in the right place! This short guide will tell you all you need to know about the coniferous trees that inhabit Oregon’s Coast Range ecoregion. Learn some fun and interesting facts about each species, as well as key identification characteristics that will help you to tell them apart.
Douglas-fir (Pseudotsuga menziesii)
The most common tree in Oregon is the Douglas-fir. A commercially valuable tree, it has been planted in much of the coastal mountains, where it naturally grows, reaching heights of over 250 feet. Douglas-fir is an early successional species, established on bare mineral soil following a fire. Much of the old-growth that remains in Oregon today resulted from large fires 400 to 600 years ago. When Douglas-fir fall, they open the canopy for species, like the western hemlock to fill in the gaps.
Douglas-fir has reddish-brown bark with deep furrows, sometimes referred to as “bacon bark” for those inclined toward food analogies. However, these furrows are not as pronounced in younger trees and coloration does seem to vary. Branches swoop upwards, capturing the light. Needles are soft and arrange themselves in even whorls on each pliable branch. Look for shiny red-pointed buds at the tips of the growing branchlets. Not a true-fir, Douglas-fir cones often fall to the forest floor, a favorite food for Douglas squirrels. Douglas-fir cones are unmistakable, with three-pronged bracts that stick out from under each scale.
Douglas-fir barkneedles and budsYoung cone
Western Hemlock (Tsuga heterophylla)
Western hemlock is a slow-growing tree, often playing second fiddle to other conifers surrounding it. This secondary successional species is adapted to the lower light conditions of the understory. When a tree falls in the forest, the western hemlock knows—growing opportunistically in gaps caused by windfall. Western hemlock trees often start their lives on a nurse log or small snags, taking advantage of the water and protection that the high ground offers.
Western hemlock has a gently drooping top that distinguishes it among look-alike conifers. Its large sweeping branches splay out casting shadows and scattering light. The blunt needles of western hemlock are soft and variable in length but average less than half an inch. The arrangement of the needles is messy—kind of like a toddler’s hair just out of bed. Shorter needles stick out from the branch, while the slightly longer, “tamer,” needles lay flat. The bark of the Western hemlock is thin and gray with shallow ridges. Western hemlock produces copious amounts of small 1–3-inch brown cones, often seen scattered on the ground or growing up in its branches.
Western hemlock with it’s droopy leaderWestern hemlock barkcones litter the ground
Sitka spruce (Picea sitchensis)
Sitka spruce is the largest spruce species on the planet. With a diameter that can grow as large as 16 feet at its base, Sitka spruce is an impressive behemoth to behold, especially in an old-growth forest setting. Only found in a narrow band along the Oregon Coast, Sitka spruce do well throughout the fog belt and in the floodplains of rivers and streams. Despite their limited range, Sitka spruce can tolerate a lot of different coastal landscapes from salty dune islands and sandy beaches to rocky headlands and tidal swamps.
Sitka Spruce trees have wide cylindrical trunks with grey-brown bark that looks like paint chipping of an old wall. Its light-colored cones have papery-thin scales with jagged edges—often seen strewn along the trail in bunches. Sitka spruce can be easy to tell apart from other coastal forest dwellers by their sharply pointed needles that stick out on short pedestals on each twig in a bottle-brush arrangement. If you grab a branch in your palm it will hurt. Just remember, “Sitka will Stick-ya.”
Sitka sprucesharp needles and budsspruce cones litter the ground
Western redcedar (Thuja plicata)
Western redcedar with its sweeping J-shaped branches of scale-like leaves and shredded red bark is one of the most beautiful species in the Oregon coastal forests. It is also one of the most useful—indigenous peoples throughout the Pacific Northwest used the rot-resistant wood for lodges, canoes, utensils, among other things. The bark was used for basketry and to make ropes, nets, and even clothing.
Stumps and snags of ancient western redcedar punctuate the forest, withstanding the test of time. Scattered amongst more dominant Douglas-fir trees or huddled together in small groves, western redcedar is a shade-tolerant species. Western redcedar grows best in moist areas in the coastal fog belt.
To identify western redcedar, look for a thinly shredded bark that runs in vertical strips. Rub your hand down the bark and it won’t splinter. Its scale-like leaves are also unusual among other conifers in the region. The leaves are folded and lie flat against the tree’s branchlets—a white bloom in the shape of butterflies line the underside in organized rows. Tiny rose-shaped cones cluster in the branches and at times can be found scattered in the forest duff.
Western redcedarwestern redcedar barkscale-like leaves with “butterflies”
Shore Pine (Pinus contorta)
Being successful on the rugged coast can be a difficult proposition. Shore pines are adapted to that challenge by taking on the shape and form of the wind. With twisted stems and matted branches, shore pines typically only grow 65 feet tall, some much shorter. Shore pines are the same species as the erect stemmed lodgepole pine that grow to 130 feet tall throughout the west at mid to high elevations.
Some of the shore pines on Oregon’s coast are planted—put in place along with invasive dune grasses and scotch broom to stabilize a naturally shifting dune landscape. Naturally, shore pines are highly adaptable growing in sandy, boggy, and rocky environments.
The easiest way to identify a shore pine is to look at its dark green needles—arranged in twisted pairs, they cluster at the tips of each branch. Larger wooden female cones, often curved, attach to the branches, while male pollen cones are smaller, reddish-green, and cluster at the tips. The bark of shore pine is dark, rough, and scaly.
Shore pineshore pine female conepollen cones
Coast Redwood (Sequoiasempervirens)
The tallest species of conifer in on the west coast—commonly reaching heights of 300 plus feet—the coast redwood is hard to miss when you encounter it. Their great height allows them to capture fog droplets on their slender needles in the fog zone where they exclusively reside. Lichen, moss, ferns, and even trees grow in soil that forms high above the earth. Then critters join the mix—creating unique arboreal ecosystems. Redwoods are also rare in Oregon—existing in only a few protected areas along the south coast.
Besides their height, coast redwoods can be distinguished by their massive trunks up to 23 feet in diameter. Thick reddish furrowed bark runs up the great length of the trunk and their roots often buttress near the ground. The coast redwood has a conical crown with branches that droop slightly. Ancient redwoods have complex crowns with many trunks. The 1-inch needles of the coast redwood lay flat, flanking each branchlet. Bright green above with a white bloom below, the needles shorten as they draw near the main branch—tapering like a bird feather. On cone-bearing branches, the taper is more pronounced and the needles are sharper. The cones of a redwood tree are small and round with deep wrinkles.
Coastal redwood bark and formCoastal redwood growing in a fairy ringunderside of redwood branch
Resources
Want to learn more about Oregon’s trees? Check out the books below.