Friday, July 29, 2016

The Hunt for Portland's Notable Trees

I was in a Portland bookstore a couple of weeks ago and noticed a new and updated edition of Trees of Greater Portland by Phyllis Reynolds. The book – yes, I bought it – features the largest of many species, along with a couple of other notables, and best of all: their addresses. The photographs are serviceable-to-poor, but of course they're poor for there is always a car or power pole or street sign in the way. That actually makes the photographs more interesting, for the behemoth trees look more bizarre and other-worldly as they sprout out of the concrete and shove themselves against the sides of buildings.

Acer macrophyllum on Greeley Ave

Quercus garryana on 29th Place

Quercus garryana at Flora Farm

So, if you want to see the largest Acer macrophyllum in Portland you go to 6733 N. Greeley Ave. The largest Cornus kousa is at 2381 NW Flanders St,* and the champion Quercus garryana is at 4620 SW 29th Place. Concerning the oak, my wife entered the address into her smart phone and a woman's voice took us right there. As soon as we entered 29th, straight ahead and up the hill was the massive oak, and I needlessly uttered, “There it is.” Those who have been to my home know that I also have a huge Quercus garryana, and though my tree is certainly taller, the 29th specimen appears to be more wide, with the trunks' circumferences about the same. The Portland oak was spread in front of a nice home, and I noticed that some of the lateral branches were secured by cable to the center of the tree. My oak does not receive such lavish care and some of its laterals have crashed down, most horribly three years ago over our driveway, just 20 seconds after my wife drove under. By coincidence I arrived home a minute later to find my shocked Haruko standing still with her mouth open and tears in her eyes.

*Flanders is the name of a character on The Simpsons, and indeed the Portland creator of the TV show was inspired by the street's name.

Another feature of the Trees of Greater Portland is nine walking tours, each with a map and a list of trees that you will encounter. In some cases you will discover the champion, but most of the time it's just notable trees – many over 100 years old. Again, these huge elms, oaks maples etc. look preposterous in their settings, kind of like Flora was amusing herself in their placement. The value of a street map with a list of accompanying trees is that you can identify the various species of elms (Ulmus), a genus I don't know much about. I could compare the “Dutch elm” (Ulmus x hollandica) with the “Siberian elm” (Ulmus pumila), and also the “Wych elm” (Ulmus glabra) and the “American elm” (Ulmus americana). Similarly with the maples, and even though I grow Acer rubrum, A. pseudoplatanus, A. saccharum, A. saccharinum and A. platanoides at the nursery for understock, I would be hard pressed to identify the various species as they loom overhead in their urban setting.

The author cites a 2002 Portland State University study that claims 26.3% of the city is covered by trees. She continues, “As I write this, Urban Forestry is in the process of documenting all 236,000 street trees in the city: the species, size, exact location and health.” Ms. Reynolds also reminds us of the benefits of urban trees – which all of us already know – and that they increase the value of a house up to 21%. Another statistic is that “The replacement value of Portland's tree canopy [in 2006] was valued at $5 billion.” I have questions about that figure, for how does one “replace” a 100-year-old oak? With a $50 (wholesale or retail?) tree from a nursery as the largest size available? The $5 billion figure sounds to me like a university analysis from a tenured professor with his cadre of graduate students, an amount that no one is able to verify.

Grandfather with map

In any case, my Grandfather and I met in NW Portland, not far from our usual Forest Park walk, to take one of the nine walking tours. Here are familiar streets with old houses and no parking, but when I drive them I can only half-notice the trees out of concern for safety, so it was nice to finally walk the 'hood. We must have looked like two old out-of-town bumpkins, for we were the only ones without piercings or tattoos. My partner consulted the map while I carried the list of trees. He would say something like, “On the next corner is tree #7,” and I would respond, “Ok, we're looking for a Japanese maple.”

Acer palmatum at Kearney St

We initially encountered an Acer palmatum, which actually was not very impressive, so I was beginning to question our fool's errand. We looked it up and down but kept our thoughts to ourselves. Then, just twenty feet away was a very good-sized maple, The tree we were looking for. Wow, that was a notable specimen. At 2367 NW Kearney St. the residence was virtually hidden by the palmatum, with most of the windows blocked from receiving any light. Reynolds reports that the house was built in 1907, and surmises “Because this is a large, classic specimen, it was probably planted not long after the house was built.”

Ulmus glabra

As I said before I know very little about the elms (Ulmus), except that U. pumila was the most dwarf of the lot. That's not surprising since it is native to Siberia. According to the Hillier Manual of Trees and Shrubs, Ulmus glabra – “glabrous, without hairs” – is commonly known as the “Wych elm” or the “Scotch elm.” Apparently the Englishmen at Hilliers don't honor the politically correct designation of “Scot's elm” instead of “Scotch elm,” but I guess the 2014 Manual was published prior to the Scots vote to stay in the union. The common name wych is a prefix, a variant of “witch,” which is probably derived from Germanic “wik,” to bend. The word elm is also of Germanic origin, the Proto-Germanic elmaz is derived from the Proto-Indo-European helem. Until my walk with Grandfather I suppose I had never seen the glabra species except for the well-known cultivar 'Camperdownii'.

Ulmus x hollandica

Ulmus x hollandica is the “Dutch elm,” and it is a natural hybrid of U. glabra and U. minor. It is the principal elm of Germany, the Netherland, Belgium, France and England, so I must have seen it plenty of times except that I didn't know what I was looking at. The dreaded “Dutch elm disease”* was first reported in 1918 in Britain, and by the 1930's the landscapes were devastated. Well damn to the Dutch some might say, except that they weren't at fault, and the name is due to “the fact that early work on the disease was carried out in the Netherlands...not that it originated there” (Hillier). In case if the Portland specimen perishes, at least I'm happy to have seen it.

*Caused by the fungus Ophiostoma ulmi, and then later by an even more aggressive species, Ophiostoma novo-ulmi. Spores of the fungus are transmitted from diseased trees to healthy trees via the elm-bark beetles, Scolytus scolytus and Scolytus multistriatus.

Ulmus americana

Ulmus americana at Overlook Park

The most impressive elm was certainly Ulmus americana, commonly known as the “White elm,” and according to Hillier the common name is due to the “ash-gray bark,” and that the species is “a large, vigorous, attractive tree...with a wide-spreading head of graceful branches.” Along this northwest Portland street the canopy was not wide-spreading, but later in east Portland in the middle of Overlook Park I experience a grand specimen that was growing under no constraints. It proudly displayed its classic form, and I don't think that I have ever seen any deciduous tree more wonderful. Who planted it and when? – the Reynolds book doesn't say, except that U. americana is native to central and eastern North America, not to Overlook Park, Portland. It was Linnaeus who first described and named the species in his Species Plantarum, published in 1753.

Careful on the road, Gramps.

My 81-year-old Grandfather likened our excursion to a treasure hunt and was really getting into it; for my part I was worried that he was overly absorbed with his map when crossing streets. If he got run over by a car I would have to continue without his help, and we were less than half way on our hunt.

Pyrus calleryana

I'm not a fan of Pyrus calleryana, the “Callery pear,” but I do admit that this cultivar's narrow crown is advantageous for street-tree use. It is also one of the most abused of urban trees as city planters install them at odd times – like August – with a little green water bag for survival. The bags are then removed for next year's plantings, and the poor pear never receives supplemental irrigation again. My home-town of Forest Grove, Oregon has been guilty of this stupidity, and to make it worse, the abuse occurred on the main entrance into town. Anyway, the Portland tree looked ok, if a little stunted, because its earth-box was only two feet in diameter. My gripe with P. calleryana is its flowers: they are a dull dirty white and smell of rotting fish, and besides the species is invasive. Calleryana was named for the Italian-French Sinologue* Joseph Callery (1810-1862) who sent specimens from China to Europe.

*Sinology is the academic study of China involving their language, literature and history.

Magnolia grandiflora

I am not particularly in love with Magnolia grandiflora either. The tree has a “fake” look, like the glossy green leaves were manufactured in some Chinese factory full of pollutants and dubious DNA. I am without it in the Flora Wonder Arboretum, and, like the “windmill palm” (Trachycarpus fortunei) the Magnolia just wouldn't fit in. The Portland tree displayed a few blossoms, and I have seen it elsewhere with flowers in late October. Grandfather offered that he has seen it in the wild (North Carolina) with leaves so large that they were reminiscent of Rhododendron sinogrande. Well, if pressed, he would have to admit that they are not nearly so big. In any case, the residents of this Hoyt Street house must enjoy the delightfully fragrant flowers and would not trade their tree for anything else.

Romneya coulteri

Though not mentioned in Reynolds' book, we encountered a single flower of Romneya coulteri, the “California tree poppy.” It is also known as the “Matilija poppy” since it can be found in the Matilija Canyon of southern California, which was perhaps named for a Chief M. who lived in Ventura County. Romneya is a rather brushy perennial, but the showy white flowers – which look like fried eggs – are the largest of any plant native to California. The genus would be doubtfully hardy at my nursery, but its survival in Portland is absolute proof that Republican policies have caused Global Warming.

Platanus x hispanica

Char Chinar

Platanus x hispanica (of Spain) is considered a hybrid between P. occidentalis – North America and Mexico – and P. orientalis, though Hillier suggests that it might be just a form of the latter. It's difficult to see from the photo but the flaking bark is attractive, and I recall it to be somewhat orange. I learned – working in a Dutchman's nursery – to hate the “Plane tree” since the hairs from the leaves and fruits cause one to cough, and I would suppose that long-term exposure could lead to serious bronchial problems. There is a 500-year-old P. orientalis planted at Kos, Greece, and it has been suggested that it was planted from a succession of cuttings from the original. It is known as the Tree of Hippocrates, under which the “Father of Medicine” taught. And at the Athenian Academy, outside Athens, there was a sacred grove of planes where the students listened to the masters and where the Peripatetics practiced philosophy. I would think that the students' coughing would interfere with their attainment of knowledge. P. orientalis can be found as a street or plaza tree, and in China I have seen old specimens in Kunming and Beijing. I also remember seeing four large trees growing on an island on Dal Lake in Srinagar, Kashmir; they were known as Char Chinar, but I didn't know at the time that they were Oriental planes.

Aesculus hippocastanum

There were a number of Aesculus hippocastanum, or “Common horse chestnut” on our tour. They were magnificent to be sure, but Portland no longer permits their planting because falling nuts are a problem for pedestrians in autumn. When in flower they make a beautiful show, but all parts – seeds, leaves and flowers – are toxic. The genus name goes back to Latin for “a variety of oak,” where oak is defined as a type of tree that grows in northern parts of the world and that produces acorns. The origin of the common name “horse chestnut” is not certain. One theory is that the mark left by the leaf stalk after its fall resembles a horseshoe with seven dots, looking like the heads of seven nails. Another theory is that the nuts are used in Turkey for curing horses of pulmonary diseases. The problem with that theory is that they do not. The best use of horse chestnuts is in the game of conkers, a British children's game where a nut is threaded onto a piece of string. The kids take turns striking each other's conker until one breaks. I first learned of this game in England at the Westonbirt Arboretum, for signs were announcing a tournament the following Sunday. Sadly I missed it because at that time I was already in Holland.

Acer saccharinum

A notable “Silver maple,” Acer saccharinum, stood at the corner of 23rd and Kearney, but it was impossible to photograph the entire canopy; however, standing beneath the monster one could understand how it received its common name. Its bole nearly filled its 4' x 5' earth plot, and it's truly a wonder that the tree survives, but indeed it looked healthy and vigorous. I wish an urban forester could explain the physical details of how these city trees function, how such a restricted rootspace can adequately nourish the tree.

Acer saccharum

Linnaeus named and described A. saccharinum in 1753 for its sugary sap, then in 1785 Quaker botanist Humphry Marshall named the “Sugar maple,” Acer saccharum, similarly due to its sugary sap. Did Marshall know the botanic name of the Silver maple? Portland's Sugar maple was majestic, though it grew with a slight lean, and I'll be sure to revisit in fall to check out its color.

Acer rubrum

Acer rubrum 'V.J. Drake'
Acer rubrum 'Vanity'

The city is chock-a-block with the “Red Maple,” Acer rubrum, and I suspect there was once a shady closed-door deal between a certain nurseryman and city hall. Probably what one sees are cultivars, selected for their narrow forms, but the Reynolds book simply lists them as A. rubrum. The species – also named by Linnaeus in 1753 – is unmistakable in early spring for its deep-red flowers on leafless stems, but according to DeBeaulieu in An Illustrated Guide to Maples, it was named for its red fall color. I have grown only one A. rubrum in my life, 'V.J. Drake', but it quickly outgrew its place and I cut it down. I assumed that I would acquire another later but never have. Oops, I just realized that I currently grow A. rubrum 'Vanity', a cultivar that gardeners either love or hate.

Acer platanoides

Acer platanoides is the “Norway maple,” and it received its specific epithet by Linnaeus due to its casual resemblance to Platanus, the “Plane tree.” The Portland tree appeared to be a seedling-grown straight species, unlike the purple-leaved platanoides cultivars you frequently see in other neighborhoods. Really, though, platanoides is nobody's favorite tree, and I suppose it's because it just gets too large. I remember back to the 2002 Maple Symposium in England where one of the speakers was a passionate Finnish professor of forest genetics who bemoaned the threatened status of the Norway maple in Europe. After her one-hour speech someone in the audience from New York popped off with, “You can have all of ours that you want since they're now considered invasive in many states.” The stunned professor stood silent with a drained face, appalled that someone could so casually dismiss her life's work, and I and others dropped our heads in embarrassment.

Acer pseudoplatanus

Another huge species was Acer pseudoplatanus, and its branches hovered onto the other side of the street. Since Linnaeus named A. platanoides for its plane-like appearance, it's odd that he repeated it again for A. pseudoplatanus. I remember asking the English maple guru, Peter Gregory, if he knew of a rootstock species compatible with Acer nipponicum. He responded that maybe pseudoplatanus would work, for it “accepts most everything,” even species that belong to a different section. I tried but received 100% failure. I mentioned earlier the DeBeaulieu book, and on page 300 is a photo of Mrs. van Hoey Smith standing next to a fantastically huge A. pseudoplatanus trunk, and another photo of a huge tree from Yorkshire, England. The species is native to central and southern Europe and the Caucasus, so the England tree was an old introduction.

Tilia platyphyllos

Betula pendula

Well, I left out a lot of other wonderful species, such as Liquidambar styraciflua, Juglans nigra, Tilia platyphyllos, Betula pendula and more, but with the map we were able to find almost everything. We couldn't find, though, an Acer japonicum, and I wondered if it had died soon after publication. In any case, as my Grandfather and I headed back to the car we encountered a few impressive buildings which were probably as old as some of the notable trees. We retired to a local coffee shop, both of us feeling content with our treasure hunt.

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