Most Common Trees Around Hillsboro

A Guide to Identifying the Most Common Trees Around Hillsboro, Oregon

Introduction

Nestled in the lush Willamette Valley, Hillsboro, Oregon, is a city blessed with a rich natural environment. The area is home to an incredible diversity of trees, from towering evergreens to vibrant deciduous species, making it a paradise for nature enthusiasts and casual walkers alike. Whether you’re exploring the scenic trails of the nearby Tualatin Hills or simply strolling through your neighborhood, knowing how to identify the most common trees can deepen your appreciation for the natural world and help you connect more meaningfully with your surroundings.

This guide is designed to help you identify the trees that dominate the landscape in and around Hillsboro. From native species that have thrived here for centuries to the ornamental trees that line city streets, we’ll explore the key characteristics that make each tree unique. Whether you’re a seasoned naturalist or a curious beginner, this guide will equip you with the knowledge you need to recognize and appreciate the trees that define Hillsboro’s natural beauty.

Also the most common trees you may see around Hillsboro actually may be non-native species but approved for streets by Washington County. Here is a link to Washington County’s approved Street Trees.

Understanding the Basics of Tree Identification

Before diving into specific trees, it’s essential to understand the basics of tree identification. This involves paying attention to several key features that vary widely between species.

Leaf Shapes and Types

Leaves are one of the most distinctive features used in tree identification. They come in a variety of shapes, sizes, and arrangements, each offering clues about the tree’s species.

Simple Leaves: These leaves have a single, undivided blade. Examples include the leaves of the Bigleaf Maple, which are large and lobed.
Compound Leaves: These consist of multiple leaflets attached to a single stem. The Oregon Ash, for instance, has compound leaves with several leaflets.
Lobed Leaves: These leaves have deep indentations, giving them a lobed appearance, as seen in the leaves of the Oregon White Oak.
Needles and Scales: Evergreen trees like pines and cedars have needles or scale-like leaves. The Western Redcedar has small, scale-like leaves, while the Douglas Fir has needles.

Bark Texture and Color

Bark is another crucial identification tool, especially in the winter when leaves are absent. Bark can be smooth, rough, flaky, or furrowed, and its color can range from grey and brown to reddish tones.

Douglas Fir: This tree’s bark is thick, rough, and deeply furrowed, with a reddish-brown color.
Western Redcedar: The bark is thin and fibrous, with a reddish-brown hue that can be easily peeled off in strips.
Oregon White Oak: The bark is thick, rough, and grey, with deep ridges and furrows.

Tree Form and Size

The overall shape and size of a tree can also help in identification. Some trees have a distinct form, such as the tall, spire-like shape of the Lombardy Poplar or the broad, spreading canopy of the Bigleaf Maple.

Seasonal Changes

Trees change with the seasons, offering additional clues for identification. In spring and summer, flowers and fruits can be identifying features. In autumn, the color change in leaves is often species-specific, such as the bright red leaves of the Red Maple.

By combining observations of these features, you can begin to narrow down the possibilities and identify the trees around you with greater accuracy.

Native Trees of Hillsboro, Oregon

Hillsboro is home to a variety of native trees that have been part of the landscape for centuries. These species are well-adapted to the local climate and play a vital role in supporting the region’s biodiversity.

Douglas Fir (Pseudotsuga menziesii)

The Douglas Fir is perhaps the most iconic tree in the Pacific Northwest. It is a towering evergreen that can grow up to 330 feet tall, though in urban settings, it typically reaches around 70-120 feet.

Identification Tips: The Douglas Fir has long, soft needles arranged spirally around the branches. The cones are unique, with three-pointed bracts that resemble mouse tails sticking out.
Bark: The bark is thick and deeply furrowed, with a reddish-brown color.
Habitat: Douglas Firs thrive in well-drained soils and are commonly found in forests and open spaces around Hillsboro.

Western Redcedar (Thuja plicata)

Known as the “tree of life” by Native American tribes, the Western Redcedar is another giant of the Pacific Northwest. It is a key species in local ecosystems and is often found in wetter areas.

Identification Tips: The Western Redcedar has scale-like leaves that are flat and arranged in fan-shaped sprays. The cones are small and rose-shaped.
Bark: The bark is reddish-brown, thin, and fibrous, peeling off in long strips.
Habitat: This tree prefers moist, shaded areas, often along streams and in dense forests.

Bigleaf Maple (Acer macrophyllum)

As its name suggests, the Bigleaf Maple boasts the largest leaves of any maple species, sometimes reaching up to 12 inches across.

Identification Tips: The leaves are large, lobed, and have five distinct lobes. In the fall, they turn a brilliant yellow or orange.
Bark: The bark is grey-brown and becomes more furrowed with age.
Habitat: Bigleaf Maples are commonly found in mixed forests, often near water sources.

Oregon White Oak (Quercus garryana)

The Oregon White Oak is a slow-growing, sturdy tree that can live for centuries. It is the only oak native to the Pacific Northwest.

Identification Tips: The leaves are lobed and turn a distinctive brown or orange in the fall. The tree produces acorns that are a key food source for wildlife.
Bark: The bark is thick, rough, and grey with deep furrows.
Habitat: Oregon White Oaks are often found in drier areas, including savannas and open woodlands.

Common Ornamental and Non-Native Trees

In addition to native species, Hillsboro’s landscape includes a variety of ornamental and non-native trees. These species are often planted in urban areas for their aesthetic appeal and adaptability.

Norway Maple (Acer platanoides)

Originally from Europe, the Norway Maple is a popular ornamental tree in North America due to its hardiness and vibrant autumn foliage.

Identification Tips: The leaves are broad with five lobes and a pointed tip. In autumn, they turn bright yellow.
Bark: The bark is grey and smooth when young, becoming more furrowed with age.
Common Uses: Norway Maples are frequently planted along streets and in parks for their shade and colorful fall display.

Cherry Blossom Trees (Prunus spp.)

Cherry blossom trees, especially the Japanese cherry (Prunus serrulata), are beloved for their stunning springtime flowers.

Identification Tips: These trees are most easily recognized by their showy pink or white flowers that bloom in early spring. The leaves are oval and serrated.
Bark: The bark is smooth with horizontal lenticels, often a reddish-brown color.
Common Locations: Cherry blossoms are commonly found in parks, gardens, and along streets in Hillsboro.

Red Alder (Alnus rubra)

The Red Alder is a fast-growing deciduous tree native to the Pacific Northwest but also widely planted as an ornamental.

Identification Tips: The leaves are oval with serrated edges and have a distinct, dull green color. The tree produces small, woody cones that persist into winter.
Bark: The bark is thin and grey, with a smooth texture that darkens with age.
Common Locations: Red Alders are often found in wetlands, along streams, and in other moist environments.

Lombardy Poplar (Populus nigra ‘Italica’)

This tall, narrow tree is easily recognized by its columnar shape, making it a popular choice for creating windbreaks or privacy screens.

Identification Tips: The leaves are triangular with a serrated edge, and the tree has a fast growth rate, often reaching 50 feet or more.
Bark: The bark is grey and furrowed, with a rough texture.
Common Uses: Lombardy Poplars are commonly planted in rows along property lines or as windbreaks in open areas.

Evergreen Trees of Hillsboro

Evergreens are a defining feature of the Pacific Northwest landscape, providing year-round greenery and important habitat for wildlife.

Western Hemlock (Tsuga heterophylla)

The Western Hemlock is the state tree of Washington and is prevalent throughout the Pacific Northwest. It is a tall, elegant tree often found in moist, shaded areas.

Identification Tips: The needles are short, soft, and arranged in a flat, feathery pattern. The cones are small and cylindrical.
Bark: The bark is thin, grey-brown, and becomes more deeply ridged as the tree ages.
Habitat: Western Hemlocks thrive in cool, damp environments, often forming dense forests.

Sitka Spruce (Picea sitchensis)

The Sitka Spruce is the largest spruce species and is notable for its coastal habitat, often found along the Pacific coast from Alaska to Northern California.

Identification Tips: The needles are stiff, sharp, and arranged in a spiral around the branches. The cones are long and slender.
Bark: The bark is thin and scaly, with a greyish-brown color.
Habitat: Sitka Spruces prefer the moist, cool climates of coastal regions and are often found in foggy, coastal forests.

Pacific Yew (Taxus brevifolia)

The Pacific Yew is a small, slow-growing evergreen known for its distinctive red bark and historical significance as a source of the anti-cancer drug, Taxol.

Identification Tips: The needles are flat, dark green, and arranged in two rows along the branches. The tree produces small, red berries.
Bark: The bark is thin, scaly, and reddish-purple.
Habitat: Pacific Yews are typically found in shaded, moist areas, often under the canopy of larger trees.

Port-Orford-Cedar (Chamaecyparis lawsoniana)

This tree, also known as Lawson Cypress, is a highly valued species both for its wood and its ornamental use.

Identification Tips: The leaves are scale-like and arranged in flat sprays. The cones are small and round, with a distinctive, intricate pattern.
Bark: The bark is reddish-brown and fibrous, peeling in long strips.
Habitat: Port-Orford-Cedar is typically found in moist, well-drained soils, often in mixed conifer forests.

Deciduous Trees of Hillsboro

Deciduous trees add a dynamic element to the landscape with their seasonal changes in color and form.

Black Cottonwood (Populus trichocarpa)

The Black Cottonwood is the largest broadleaf tree in the Pacific Northwest, known for its towering height and heart-shaped leaves.

Identification Tips: The leaves are large, triangular, with a pointed tip and serrated edges. The tree produces fluffy seeds in late spring.
Bark: The bark is grey and deeply furrowed, with a rough texture.
Habitat: Black Cottonwoods are commonly found along rivers, streams, and in other wet environments.

Red Maple (Acer rubrum)

The Red Maple is a popular ornamental tree known for its brilliant red foliage in the fall.

Identification Tips: The leaves are palmate with three to five lobes, and they turn a vibrant red in the fall. The tree also produces red flowers in early spring.
Bark: The bark is smooth and grey when young, becoming more ridged and furrowed with age.
Common Locations: Red Maples are commonly planted in urban areas for their shade and seasonal color.

Oregon Ash (Fraxinus latifolia)

The Oregon Ash is a native deciduous tree commonly found in wetland areas. It is known for its compound leaves and winged seeds.

Identification Tips: The leaves are compound with five to seven leaflets, and the tree produces distinctive, paddle-shaped seeds.
Bark: The bark is grey and ridged, becoming more furrowed with age.
Habitat: Oregon Ash trees are typically found in wet, lowland areas, often near rivers and streams.

Western Dogwood (Cornus nuttallii)

The Western Dogwood is known for its striking white flowers and red berries, making it a favorite ornamental tree.

Identification Tips: The leaves are oval with smooth edges, and the tree produces clusters of white flowers in the spring, followed by red berries.
Bark: The bark is smooth and grey, with a somewhat mottled appearance.
Common Locations: Western Dogwoods are often found in mixed forests and are also planted as ornamentals in parks and gardens.

The Role of Trees in Hillsboro’s Ecosystem

Trees play a critical role in maintaining the ecological balance in and around Hillsboro.

Habitat and Biodiversity

Trees provide essential habitat for a wide range of species, from birds and mammals to insects and fungi. Native trees like the Douglas Fir and Oregon White Oak are particularly important, as they support local wildlife that has evolved alongside them.

Erosion Control and Water Regulation

Trees help to stabilize the soil and reduce erosion, particularly on hillsides and along waterways. Their roots also play a crucial role in regulating water flow, reducing the risk of flooding, and maintaining the water quality in streams and rivers.

Cultural and Historical Significance

Many of the trees around Hillsboro hold cultural and historical significance, especially for the indigenous peoples who have lived in this region for millennia. For example, the Western Redcedar has been used for centuries by Native American tribes for building, crafting, and ceremonial purposes.

Urban Tree Management

In urban areas, trees are carefully managed to enhance the quality of life for residents. The city of Hillsboro has several programs aimed at maintaining and expanding the urban tree canopy, recognizing the many benefits trees provide, from improving air quality to reducing the urban heat island effect.

Practical Tips for Tree Identification in the Field

Identifying trees in the field can be a rewarding experience, especially with a few practical tips in mind.

Using Field Guides and Apps

Field guides are invaluable tools for tree identification. Books like Trees of the Pacific Northwest by Mark Turner and Ellen Kuhlmann are excellent resources. Additionally, smartphone apps like iNaturalist and PlantSnap can help identify trees based on photos.

Seasonal Observations

Paying attention to the seasonal changes in trees can aid identification. In spring, look for flowers; in autumn, note the color changes; and in winter, focus on bark texture and tree form.

Noticing Tree Communities

Certain trees often grow together, forming specific communities. For instance, finding a Douglas Fir might indicate that Western Hemlocks or Bigleaf Maples are nearby, as these species commonly share the same habitat.

Final Thoughts

Hillsboro, Oregon, is home to a diverse array of trees, each contributing to the beauty and ecological richness of the region. From towering evergreens to vibrant deciduous species, these trees are an integral part of the landscape. By learning to identify the most common trees around Hillsboro, you can deepen your connection to the natural world and gain a greater appreciation for the unique environment in which you live. Whether you’re exploring local parks, hiking in the surrounding forests, or simply enjoying a walk through your neighborhood, the knowledge of these trees will enhance your experience and foster a deeper understanding of the importance of preserving these natural treasures.