Category Archives: Large Trees

Oregon White Oak

Oregon White Oak (Quercus garryana)
Quercus garryana

Oregon white oak, also known as Garry oak or Oregon oak, is a drought tolerant tree that grows slowly to around 65-80 ft. The leaves are deciduous, 3-6″ long and 2-5″ broad, with 7-9 deep lobes on each side. The flowers are catkins, the fruit a small acorn about 1″ long, with shallow, scaly cups.

In the Willamette Valley, oaks are common habitat for mistletoe Phoradendron flavescens and gall wasps Cynips maculipennis. Gall wasps have a unique survival strategy: they secrete chemicals that interfere with the oak’s normal growth hormones, which causes small, abnormal growths on the underside of leaves wherever eggs are laid. The gall grows around the developing gall wasp larvae and provides them food and shelter. Galls normally do not harm oaks, though heavy infestations can stress trees. The Garry oak is also the only known food for Bucculatrix zophopasta caterpillars.

History and uses

Before the European settlers came into the Willamette Valley, the oaks were mostly open-grown individual trees due to the burning practices of the native Calapuya people. Now, wildfires are almost unknown in the Willamette Valley. Since the settlers did not continue this practice, the intervening land was soon covered with seedling oaks (called “scrub oaks” by the settlers) which grew vertically and formed a closed canopy. Remnants of the old open-grown oaks are still found in these closed oak stands.

Although the wood has a beautiful grain, it is difficult to season without warping and therefore the Garry Oak has not historically been regarded as having any commercial value and is frequently destroyed as land is cleared for development. However, Garry Oaks and their ecosystems are the focus of conservation efforts, including in communities such as Oak Bay, British Columbia, which is named after the tree, and Corvallis, Oregon. Moreover, recently the wood, which is similar to that of other white oaks, has been used experimentally in Oregon for creating casks in which to age wine.

Oregon white oak ranges from southern California to extreme southwestern British Columbia, particularly southeastern Vancouver Island and the adjacent Gulf Islands. It grows from sea level to 210 m altitude in the northern part of its range, and at 300-1800 m in the south of the range in California. The tree is named after Nicholas Garry, deputy governor of the Hudson’s Bay Company, 1822-35.

  • Light Requirements: Full Sun
  • Water Requirements: Dry, Moist
  • Ease of Growing: Moderate
  • Growth Rate: Slow
  • Spreads: No
  • Wildlife Support: Pest-eating Insects, Birds or Mammals
  • Edible: No
  • Mature Height: 25-70ft
  • Mature Width: 30-60ft

Western Redcedar

Western redcedar (Thuja plicata)
Thuja plicata

Western redcedar is a species of Thuja, an evergreen coniferous tree native to the northwestern United States and southwestern Canada.

The foliage forms flat sprays with scale-like leaves in opposite pairs, with successive pairs at 90 degrees to each other. The small cones dangle off the ends of the branches.

Western redcedar is a large tree, reaching 100-200 feet tall and 9′ or more trunk diameter at maturity. The largest known Western redcedar grows near the northwest shore of Lake Quinault near Aberdeen, Washington. It is over 170 feet tall and nearly 20 feet in diameter.

Western redcedar is among the most widespread trees in the Pacific Northwest, often found growing with Douglas-fir and Western hemlock in lush forests, as well as in forested swamps and along streambanks. The tree is shade-tolerant, and able to reproduce under dense shade.

In the American horticultural trade, it is sometimes called Giant Arborvitae. The name Western redcedar is also sometimes split into three words as ‘Western Red Cedar’ (though this can be confusing, as it is not a true cedar).

Native American Uses

Western redcedar is one of the most culturally significant trees for Native American people of the Pacific Northwest. Its wood, bark, and branches have dozens of practical uses, ranging from tools and housing to cloth and ceremonial implements. Nearly every part of traditional indigenous culture uses redcedar in some fashion, and some northwest coast tribes even refer to themselves as “people of the redcedar,” so central it is to their identity and way of life.

  • Light Requirements: Full Sun, Part Shade, Full Shade
  • Water Requirements: Moist, Seasonally Wet
  • Ease of Growing: Easy to grow
  • Growth Rate: Moderate
  • Spreads: No
  • Wildlife Support: Birds or Mammals
  • Edible: No
  • Mature Height: 100-200ft
  • Mature Width: 30ft

Western Hemlock

Western hemlock (Tsuga heterophylla)
Tsuga heterophylla

Tsuga heterophylla, commonly known as the Western Hemlock, is the largest species of hemlock growing to 200′ tall, and with a trunk diameter of up to 4′. The tallest specimen, 78.9 m tall, is in Prairie Creek Redwoods State Park, California. It is long-lived, with trees over 1200 years old known.

Western hemlock bark is thin, furrowed, and brown. Young trees have a broad conic shape with a strongly drooping lead shoot. At all ages, it is readily distinguished by the pendulous branchlet tips. The needles are short, averaging less than 1″ long, strongly flattened in cross-section, mid to dark green above, and with two broad bands of white stomata below with only a narrow green midrib between the bands.

The cones are small, pendulous, slender, and cylindrical, 1-3″ long with thin, flexible scales. The immature cones are green, maturing gray-brown 5-7 months after pollination. It is a very shade-tolerant tree, with young plants typically growing up under the canopy of other conifers such as Sitka Spruce and Douglas-fir. Without disturbance, hemlocks eventually dominate the canpoy, as other conifers cannot grow in their dense shade. However, storms and (rarely) wildfires create openings in the forest where less shade-tolerant species can regenerate.

Western Hemlock is the state tree of Washington.

Cultivation & Uses

Western Hemlock is cultivated in its native territories, where its best reliability is seen in wetter regions.

Western Hemlock boughs are used to collect herring eggs during the spring spawn in southeast Alaska. The boughs provide an easily collectible surface for the eggs to attach to as well as provide a distinctive flavor. This practice originates from traditional gathering methods of the Tlingit people.

The edible cambium can be collected by scraping slabs of removed bark. The resulting shavings can be eaten immediately, or can be dried and pressed into cakes for preservation. The bark also serves as a source of tannin for tanning.

Western Hemlock is also an important timber and paper tree, and is grown worldwide as an ornamental species.

  • Light Requirements: Full Sun, Part Shade, Full Shade
  • Water Requirements: Dry, Moist
  • Ease of Growing: Easy to grow
  • Growth Rate: Fast
  • Spreads: No
  • Wildlife Support: Pest-eating Insects, Birds or Mammals
  • Edible: No
  • Mature Height: 120-200
  • Mature Width: 30-40ft
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