A Guide to Identifying Trees While Hiking: Wallowa Mountains, Oregan

Engelmann Spruce (Picea engelmannii)

The Engelmann Spruce is a conifer that thrives in the high elevations of the Wallowa Mountains. It can reach heights of 80 to 130 feet and is known for its resilience in harsh climates. The tree has a narrow conical shape with a straight trunk and dense branches. Its cylindrical cones are 1.5 to 3 inches long and hang down from the branches. The slender, pointed, blue-green needles grow singly from all sides of the twig, giving the branches a full appearance. The bark is thin, scaly, and reddish-brown, turning grayish with age and often forming small, irregular plates.

Engelmann Spruce forests provide crucial habitat for a variety of wildlife, including birds, mammals, and insects. Birds such as crossbills and grouse feed on the seeds, while mammals like deer and elk use the dense cover for shelter. Engelmann Spruce forests are popular destinations for outdoor activities such as hiking, camping, and wildlife observation.

Fun Fact: The tree is named after George Engelmann, a 19th-century botanist who made significant contributions to the study of North American plants.

Subalpine Fir (Abies lasiocarpa)

Subalpine Fir is exceptionally well-adapted to the cold, harsh conditions of high-elevation environments. Subalpine Fir typically grows to heights of 60 to 100 feet. The narrow, spire-like shape of Subalpine Fir is a striking feature, making it easily recognizable in the wild. Its narrow, spire-like shape helps it withstand heavy snow loads and high winds. The needles are short, soft, and flat, with a bluish-green hue. They grow densely along the branches, giving the tree a lush, full appearance.  The bark is thin and smooth on young trees, becoming rough and furrowed with age. The cones fade from purple to reddish-brown with age, and strangely, sit upright on the branches. The cones disintegrate at maturity to release seeds, a common characteristic of fir trees. 

Subalpine Fir forests provide critical habitat for a variety of wildlife, including birds, mammals, and insects. The dense foliage offers shelter, while the seeds are a food source for various species including the Clark's Nutcracker, pine grosbeak, and snowshoe hare. Larger mammals like deer and elk also rely on these forests for cover and food.

Lodgepole Pine (Pinus contorta)

Lodgepole pine is a versatile tree that can tolerate a range of elevations. Its ability to thrive in poor, rocky soils makes it a resilient species in the challenging environments of the Eagle Cap Wilderness. Lodgepole Pines typically grow to heights of 70 to 80 feet but can reach up to 100 feet in optimal conditions. They have a slender, straight trunk with a narrow, conical crown.  The yellow-green needles are mid-length and grouped in pairs. They are slightly twisted and grow densely along the branches. The thin bark is scaly and can range from brown to black. It becomes more deeply furrowed with age. The cones are small with prickly scales, often remaining closed and attached to the tree for many years, opening only in response to the heat of a fire. This adaptation allows Lodgepole Pine to quickly colonize areas after a fire, making it a pioneer species in post-fire succession. 

Lodgepole Pine forests provide habitat for a variety of wildlife, including birds, mammals, and insects. Species such as woodpeckers, squirrels, and snowshoe hares rely on these forests for food and shelter.   The root systems of Lodgepole Pine help stabilize soil in steep, rocky areas, reducing erosion and maintaining watershed health. This is particularly important in the rugged terrain of the Eagle Cap Wilderness.

Mountain Hemlock (Tsuga mertensiana)

Mountain Hemlock is exceptionally well-adapted to high-elevation environments' cold, snowy conditions. Its flexible branches and drooping top help it shed snow, reducing the risk of breakage.  This species can grow in nutrient-poor soils and areas with short growing seasons, making it a key tree in the rugged landscapes of the Eagle Cap Wilderness.  Mountain Hemlock is highly shade-tolerant, allowing it to thrive in dense forests and contribute to the layered structure of subalpine ecosystems. They typically grow to heights of 40 to 100 feet but can reach up to 150 feet in optimal conditions. It has a narrow, conical shape with a gracefully drooping top and branches.  The blue-green needles are very short and flexible. They radiate evenly around the twig, giving the branches a bushy appearance. The scaly bark is thin and becomes furrowed and rough with age.  The cones are small and hang downward, starting out purple and brown-out as they mature.

Mountain Hemlock forests provide critical habitat for a variety of wildlife, including birds, mammals, and insects. The extensive root systems of Mountain Hemlock help stabilize soil on steep slopes, reducing erosion and maintaining watershed health.

Whitebark Pine (Pinus albicaulis)

Typically found at elevations between 7,000 and 10,000 feet, the whitebark pine is a hardy tree that often grows in rocky and exposed areas. They typically grow to heights of 40 to 60 feet but can be shorter and more stunted at higher elevations due to harsh conditions. It often has a twisted, gnarled appearance with a broad, irregular crown. The bluish-green, curved needles are grouped in bundles of five and are densely packed along the branches. The bark is thin, smooth, and white to light gray on young trees, becoming thicker, furrowed, and darker with age.  The cones are small, fading from dark purple when immature and ripening to a modest brown color. Unlike other pine species, Whitebark Pinecones do not open on their own but rely on birds to disperse their seeds. The bird buries the seeds in the ground, some of which are forgotten and can germinate, leading to the establishment of new trees. This mutualistic relationship is essential for the regeneration of Whitebark Pine forests. 

Whitebark Pine seeds are a vital food source for many species, including Clark's Nutcracker, red squirrels, and grizzly bears. The trees also provide habitat and nesting sites for birds and other wildlife.  The roots of Whitebark Pine help stabilize soil on steep slopes, reducing erosion and maintaining watershed health. The trees also influence snow retention and melting, which affects water availability downstream.

Aspen (Populus tremuloides)

Aspens thrive in a variety of climates but are particularly common in cooler, higher-elevation environments above 5,000ft. They prefer moist, well-drained soils and are often found near streams, lakes, and in meadows. Aspens are considered an indicator species, reflecting the health of the ecosystems they inhabit. Their presence often signifies a well-balanced, diverse environment. Aspens typically grow to heights of 20 to 80 feet, with a slender, upright form and a rounded or irregular crown. The bright green leaves are nearly round with finely serrated edges and a flat petiole, causing them to "quake" or tremble in the wind.  In the fall, the leaves turn a vibrant yellow. The bark is smooth, white to greenish-gray, and often marked with black knots or scars called "eyes". Interestingly, the Aspen's bark contains chlorophyll, allowing photosynthesis to occur even when leaves are absent. This adaptation helps the tree survive in colder climates and during shorter growing seasons. One of the most unique aspects of Aspen is its ability to form large clonal colonies through root suckering. A single root system can give rise to numerous genetically identical trees, which can spread over extensive areas and live for thousands of years. 

Aspen groves provide essential habitat for various wildlife, including birds, mammals, and insects. The trees offer nesting sites, food, and cover. Elk, deer, and moose commonly feed on Aspen bark and leaves.  The understory vegetation in Aspen groves is often rich and varied, supporting pollinators and other wildlife.  The root systems of Aspens help stabilize soil, reducing erosion and promoting water retention.

Douglas Fir (Pseudotsuga menziesii)

While more common at lower elevations (between 4,000 and 8,000 feet), Douglas fir can be found in some areas of the Eagle Cap Wilderness. This tree thrives in a variety of climates but prefers areas with moderate to high precipitation and well-drained soils. Douglas Fir trees can reach impressive heights of 40 to 300 feet, with a straight, cylindrical trunk and a conical crown. Older trees often have a rounded or irregular crown due to their age and environmental conditions. The needles are soft, flat, and roughly 1 inch long, with a distinct fragrance when crushed. They are arranged spirally around the branches and have a slight groove on the upper surface. The bark is thick, deeply furrowed, and dark brown on mature trees, providing excellent fire resistance. Younger trees have smoother, grayish-brown bark. The cones are distinctive, hanging downward and measuring 3 to 4 inches long. They have three-pointed bracts that extend beyond the scales, resembling the hind legs and tail of a mouse. 

Douglas Fir forests provide essential habitat for a variety of wildlife, including birds, mammals, and insects. Species such as owls, squirrels, and deer rely on these trees for food, shelter, and nesting sites.  The extensive root systems of Douglas Fir trees help stabilize soil, reduce erosion, and regulate water flow in forested watersheds.

Fun Fact: The Douglas Fir is the state tree of Oregon, symbolizing its ecological and economic importance to the region. Douglas Fir is a popular choice for Christmas trees due to its symmetrical shape, strong branches, and pleasant fragrance. 

Ponderosa Pine (Pinus ponderosa)

The Ponderosa Pine thrives at elevations between 3,000 and 7,000 feet and prefers hot, dry summers and cold, moist winters. It is commonly found in well-drained soils and can tolerate drought conditions. Ponderosa Pines are among the tallest pine species, often reaching heights of 60 to 200 feet. They can live for several hundred years, with some individuals exceeding 600 years. This longevity allows them to play a long-term role in forest ecosystems.  These pines have a straight, cylindrical trunk and a broad, open crown. Younger trees have a more conical shape, which becomes more irregular as they age.  The needles are over 5 inches long, slender, and grouped in bundles of two or three. They are bright green to yellow-green and emit a characteristic turpentine-like fragrance when crushed. The cones are ovoid with thick, sharp-pointed scales. They open to release winged seeds, which are dispersed by the wind.  The bark of mature Ponderosa Pines is thick, deeply furrowed, and orangish-brown to cinnamon-red, often described as resembling puzzle pieces. The bark also emits a unique vanilla or butterscotch scent, particularly noticeable on warm days. This aroma is due to the volatile compounds present in the bark resin.  

Ponderosa Pine forests provide essential habitat for various wildlife species, including birds, mammals, and insects. Species such as woodpeckers, squirrels, and mule deer rely on these trees for food, shelter, and nesting sites.

Fun Facts: The Ponderosa Pine's thick, fire-resistant bark often bears scars from past fires, providing valuable information about the historical fire regimes in a given area.  "Ponderosa" means "heavy" in Latin, referring to the tree's dense wood.