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Five Oaks: Seattle's Four Common Exotic Oaks
and Its Rare Native One
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While there are several hundred species of oak, and a multitude of hybrids, Seattle is dominated by four common kinds. These common introduced oaks and our native Oregon white Oak will be featured here to the exclusion of the various rarer sorts.
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| Introduced Oaks |
| The English oak (Quercus robur), a white oak, is the most abundant oak in the city's older parks, including Washington Park Arboretum.. Almost every park landscaped by the Olmsted Brothers has this. Today, although it is rarely planted, it plants itself, reproducing rampantly in our parks and verily wherever it is able; seedlings and saplings abound. In the Arboretum one can observe many sapling English Oak tenaciously holding their rich green leaves as late as mid-November --long after the other oaks have turned color. This species owes its successful reproduction to three factors: its abundance, its regularly-set crops of large acorns, and its relatively strong shade-tolerance. |
| When given full sun the tree flourishes, developing a broad crown and massive trunk. One on Kinnear bluff, planted in the 1890's, has a diameter of over three feet. When shaded in thick woods as in Interlaken Park, a skinny trunk shoots up like a telephone pole 75 or more feet high, with few limbs near the ground. In Europe where it is native, the largest specimens achieve 150 feet and generally unequalled girth. Centuries-old trees are much venerated by the people there. |
Of all the trees on earth, few have been more celebrated and worshipped, or have played a more active role in human history. This is THE tree of the British, monarch of that forested isle; with its timber were built the sturdy ships that helped to establish an empire. No tree is more mentioned in English poetry, song and literature. But it is not only the British who are fond of the tree; something about the oak makes us all revere and admire it, as expressed by Virgil in his second Georgic, in Dryden's famous translation:
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| Jove's own tree, |
| That holds the woods in awful sovereignty, |
| Requires a depth of lodging in the ground, |
| And, next the lower skies, a bed profound. |
| High as his topmost boughs to heaven ascend, |
| So low his roots to hell's dominion tend; |
| Therefore nor winds, nor winter's rage, o'erthrows |
| His bulky body, but unmoved he grows. |
| For length of ages lasts his happy reign, |
| And lives of mortal men contend in vain. |
| Full in the midst of his own strength he stands, |
| Stretching his brawny arms, and leafy hands: |
His shade protects the plains, his head the hills commands.
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| Pin oak (Quercus palustris), a red oak, was little used in the Olmsted-designed parks, but has been very widely used since then, especially as a street tree. It is aptly called pin oak; in every respect the trees are distinctly skinny; a slender straight trunk, numerous slim, elongated drooping branches and pin-like twigs bearing finely cut leaves with spined lobes. |
| As the trees mature they can take on a bristling appearance from the fiercely clinging twigs and branches, best observed in old, unpruned trees. Four such can be seen in the Arboretum near the boulevard midway between Boyer Avenue and the viaduct overpass. Most of the pin oaks in this region never approach the twiggy density of the Arboretum group. One of the biggest pin oaks in the city is literally surrounded by a pigsty at the zoo, but protected from the pig. The tree is somewhat atypical in appearance. |
| Pin oaks are popular due to their pleasing outline, bright fall color, ease of transplanting and rapidity of growth. The young trees, as with many other oak species, tend to hold their leaves throughout the winter, brown and dead but still attractive, until the swelling buds of spring pop them to the ground. This feature is less marked on busy arterial streets than on quiet residential ones. Acorns are produced in abundance, but seedlings are uncommon in Seattle. There is, however, a definite problem associated with the pin oaks: their habit of forever thrusting their long skinny limbs into everyone's way. In spite of pruning, the branches will continue to grow; prune one, the next one up begins to droop; cut the tree down and the stump will send up suckers. Certain cultivars such as 'Crownright' need less pruning. |
| Red oak (Quercus rubra) is the opposite of the pin oak in every respect except rapidity of growth. It is a massive tree, with a short stout trunk that quickly forks into gigantic, sturdy limbs, which spread into a very broad crown. The leaves are huge and wide, but shallowly lobed. Native in the eastern United States like the pin oak, it grows on better soils and can achieve a maximum height of 160 feet with a trunk sometimes more than eight feet in diameter. One of Seattle's finest specimens is on the lawn northwest of Savery Hall, on the University of Washington campus. It is commonly seen in parks and in the gardens of old mansions, but is too large for most street planting strips and thus is scarcely seen as a street tree. The acorns are large and seedlings not uncommon. |
Scarlet oak (Quercus coccinea) is intermediate in appearance between the pin and red oaks. Where the pin oak is thin and twiggy and the red oak is gargantuan, the scarlet oak seeks the prudent middle ground. It takes after the red oak in trunk habit, and after the pin oak in leaf shape. The Arboretum has exemplary ones near the Lynn Street parking lot. They were planted in 1938, and are labelled. The Federal Courthouse downtown has twenty of these on its spacious lawn, as well as some pin oaks.
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| The Native Garry Oak |
| Having considered the four fairly abundant exotic oaks of Seattle, we now turn to our decidedly rare native species, the Oregon white or Garry oak (Quercus Garryana). It is able to survive in exposed, dry, miserably parched areas such as the vicinity of Victoria, British Columbia, and in these places is a slow-growing tree. In Seattle the only wild ones of any significant size and age appear to be limited to the Seward Park area, where a combination of well-draining soil and strong southern exposure makes for a habitat that few trees can tolerate. Cultivated specimens are found throughout the city, and usually appear to be sturdy, carefree trees. |
| The Oregon white oak is a distinctive species, having very stout twigs terminating in large hairy buds, and leaves of a heavy texture, dark green and rough above, pale and downy beneath, with irregular, rounded lobes. The only oak in Seattle that one might mistake for it is the English oak (Quercus robur). |
| The tree suffers from a widely-held myth that it is always a very slow grower. Where it grows naturally it is usually slow, but when cultivated in Seattle it is by no means our slowest-growing oak. When it receives ample moisture and rich soil, it makes a superb street tree. Two can be seen as such where E Ward Street meets 26th Avenue E, very close to the Arboretum, and one on Harvard Avenue between Harrison and Republican Streets (The Harvard Avenue oak was cut down in the summer of 1987). |
| An interesting aspect of the tree is its gall production. Galls are swellings of plant tissue generally caused by insects, to give a home for their brood. In our area galls are easily observed on willow, poplar, spruce, linden, box, kinnikinnick and rosaceous shrubs. One type of gall on the native oak fairly shouts for attention: it is large and buff colored, from two to four inches in diameter, round or nearly so, occurring singly or in clusters. These galls would make fine fish floats or could be used admirably in arrangements of dried plant material; when young and tender they are edible, although astringent if eaten raw. The Oregon oak gall wasp (Andricus spongiolus) is the insect instigator of this particular type of curious vegetable ball. For some reason, certain trees are galled and others left alone. |
In closing, I urge all people interested in specimen trees to make a visit to see the splendid Oregon white oak at Oak Manor apartments, 730 Belmont Avenue E, on Capitol Hill. It is one of the most outstanding specimen trees of any kind in the city. Fred Anhalt, local architect and builder who has produced many acclaimed buildings in town, including these, responded to my inquiry about the old oak. "When I built the apartment building in 1928 the tree was about one half of the size that it is now. How old it would have been then I cannot tell you. The tree has doubled its size in width and also in height since 1928. It has been protected with a fence around it and with no other plants under it. It has received the same care as any other plants and trees planted at that time."
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(Originally published in the Summer 1983 University of Washington Arboretum Bulletin, pages 10 - 13, along with some illustrations.)
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