local ecologist

June 21 is the summer solstice and the official start of summer but the presence of linden flowers is a good sign that summer is already here. The flowers bloom “for about two weeks, when spring turns to summer,” according to Plotnick in The Urban Tree Book. The linden (genus Tilia) pictured above is not a littleleaf (T. cordata) or a silver linden (T. tomentosa), common lindens on the streets of Boston where I worked as an urban forester. I think it is a bigleaf linden or T. platyphyllos.

The leaves of the lindens tend to be heart shaped with imperfect – lopsided – bases. The leaves end in long points, a perfect design for directing water to the root zone. The lindens also grow a second type of leaf known as a bract, a “more or less modified leaf situated near a flower or inflorescence” (H.D. Harrington in How to Identify Plants). The bracts frame the lindens’ flowers (pictured above).
Both the flowers and leaves of the linden offer something sweet. The sap produced in the leaves attract aphids who greedily drink too much and excrete it on the leaves and anything below the canopy of the tree. Many animals benefit from this excreted sap; ants, flies, and moths eat it as well as “a sooty mold that blackens the leaf” (A. Plotnick).

Plotnick describes the perfume of the linden’s flowers as “a floral mist” that is “diffused…through the neighborhood.” The flowers are complete; they have sepals, petals, stamens, and pistils. Bees pollinate the flowers, but there is a price to be paid for the abundance of flowers, pollen, and nectar. Plotnick writes that silver and Crimean lindens produce a toxic substance that seems to be concentrated in pollen. Bumblebees tend to eat pollen. Honeybees extract nectar which is less toxic. Cultivated linden honey is “sold as a delicacy and used in liqueurs.” The flowers are also steeped to make an herbal infusion – tilleul – in France.

I’ve written about the genus Aesculus on this blog. The ones that grow along Adeline Street near the Berkeley Bowl are horsechestnut or A. hippocastanum. I am most familiar with this species; there were several in front of the parks department building when I worked in Boston. During my time there one was killed by an errant driver. The horsechestnut flowers have peaked but the California buckeye’s (A. californica) flowers are still in bloom. The tree pictured above grows north of the alumni house on the UC campus. There is a buckeye growing as a street tree on Parker Street at Dana in the Le Conte neighborhood.

The buckeye, like the horsechestnut, has a palmate leaf (spread apart your fingers for a rough visual aid) but its leaves are narrower than those of the horsechestnut. There are three types of palmate gemoetry: divided, parted, and compound. The leaves of the genus Aesculus are compound.

On to the flowers. If the branch structure of the buckeye is like a candelabrum (A. Plotnick), then the flowers are its lights! In fact, Plotnick writes that buckeyes and horeschestnuts are refered to as “candle trees.” The geometry of the floral cluster is a thyrse described by H.D. Harrington as “a cylindrical or ovoid-pyramidal, usually densely flowered panicle on the order of a cluster of grapes or a lilac inflorescence.” There are 100 – 200 blossoms per thyrse and like the linden, the smell is intoxicating. The smell is described by A. Plotnick as “a soapy summery aroma.” Plotnick provides a description of the complexities of floral design:

The individual flowers could not be more gracefully structured or inviting. Examine them closely. Pollen sacs are extended on long wiry filaments. A sweet nectar lures pollen spreaders along the female parts. Color makrings on the petals provide ‘honey guides’ for the clueless. And when the sweet stuff is used up, the petals undergo color changes from yellow to orange and carmine, signaling, MISSION ACCOMPLISHED. VISIT OUR OTHER FINE BLOSSOMS (p. 244).

Like the linden, the horsechestnut and buckeye are toxic, but in this case it is the seed not the flower, and the toxicity is towards humans, not bees. The horsechestnut has been confused with the American chestnut, Castanea dentata, which is related to beeches (genus Fagus), native to the eastern U.S. , and was decimated by an Asian fungus between 1904 and the 1930s (A. Plotnick). The chestnut seed is edible but not the horsechestnut or buckeye seed. The latter contains a substance known as esculin “that destroys red blood cells” when ingested; esculin can be extracted via boiling (A. Plotnick).

Source: Forestry Images, Univ. of Georgia, Warnell School of Forestry and Natural Resources

The common names – horsechestnut and buckeye – were derived from “associations with horses,” according to Plotnick. For example, the buckeye’s seed resembles the eye of a horse because of the helium – “the scar where the seed broke away from the fruit” (H.D. Harrington) – which resembles an iris. Also, the leaf scar (where the leaf was attached to the stem) resembles a horseshoe (pictured above).

Tuliptree, bird of paradise, bottlebrush. Common names of commonly seen plants in Berkeley. The names derive from the appearance of each plant. The flowers of the tuliptree, Liriodendron tulipfera, look like tulips. The bird-of-paradise flower, Strelitzia genus, resembles the bird of paradise (Paradisaeidae family). Obviously the flower of the bottlebrush tree, Callistemon genus, resembles a bottle brush.

The 16th century name for the ginkgo (Ginkgo biloba) was ya-chio-tzu which means “a tree with leaves like a duck’s foot,” according to Arthur Plotnick in The Urban Tree Book.

Two common names for the catalpa (Catalpa speciosa), which I have not seen in Berkeley, are derived from the appearance of the plant’s seed pod: cigar tree and Indian bean tree. I think the pods, pictured below, look like a green bean or vanilla bean.

Source: USDA Plants Database

Another tree with a common name derived from the appearance of its fruit is the sycamore or planetree, which is commonly planted in Berkeley. The tree is known as buttonball tree. Each button ball or fruit is an “aggregate of achenes.” An achene is a “small dry, -1-celled, 1-seeded indehiscent fruit, the seed attached to the pericarp at 1 place” (Harrington, How to Identify Plants). If the tree has one seed ball per stalk, then it is an American sycamore versus the London planetree which would have two or three seed balls per stalk.

Could parking space become the next living space? asked Elsa Brenner of the New York Times in an article of the same name. Brenner wrote of a Westchester County Department of Planning study that proposes to increase housing for moderate-income households by building on office park parking lots. Brenner, quoting from the study, notes that office parks, constructed with roads and utilities, lower development costs on these sites.

Where do trees fit? Well, the article (I am really enjoying my Times subscription) reminded me of photographs I took of the North Berkeley and Ashby BART parking lots. I’d like to share some thoughts about both lots. First, note the large stature trees, pictured below, that provide visual privacy between the North Berkeley station and houses to its west. Also note the small stature trees, pictured above, in the expanse of asphalt on the western side of the North Berkeley BART station. Then, compare the shade profile of a short stature tree, in this case, a purple leaf plum to that of a larger stature tree, a sweetgum (photo below). Importantly, the sweetgum is not at its mature size.

My look at the two BART station was not a compare and contrast exercise. I did not photograph the western parking at Ashby BART which more closely resembles the North Berkeley station. I did photograph the eastern lot at Ashby which has remarkable trees, pictured below.

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Spring has definitely arrived. In its earlier days I meant to post about buds, leaves and flowers. Better late than never. The following material is quoted from two of my favorite botany books: Botany for Gardeners by Harold William Rickett and Trees: Their Natural History by Peter Thomas.

This is a bud. This complex structure, beautifully and symmetrically formed of successively overlapping young leaves and including the apical meristem of a stem-all this is comprised in that simple three-letter word. Any bud is potentially a length of stem with the leaves that will adorn it. As the cells lengthen, forming a region of elongation, the leaves which were at first so close-packed at the tip become separated. The cells which were once included in the shirt, broad meristem of the apex now form the length of stem beneath the tip; and leaves which were once crowded on the apex are now attached on the sides of this length of stem, often at wide intervals.

Buds of different trees vary in just how much of the next year’s growth is preformed. In fact buds can be divided into three types of growth. In trees such as ashes, beech, hornbeams, oaks, hickories, walnuts, horse chestnuts and many maples and conifers, the whole of next year’s shoot is preformed. Everything is preformed or fixed in the bud as it develops over the summer to be expanded into a branch the following spring. These species are described as showing fixed or determinate growth. Since everything is preformed, spring growth occurs in a single, rapid flush and is over in just ten days to a few weeks, and then the terminal bud takes on its winter appearance.

In many others, however, only some of the leaves are preformed….Trees showing this free or indeterminate growth (sometimes called continuous growth) include elms, limes (lindens), cherries, birches, poplars, willows, sweetgums [pictured above], alders, apples, and conifers such as larches, junipers, western red cedar, the coastal redwood and ginkgo….Growth continues for longer in determinate species but still normally stops well before the end of the growing season, giving time for next year’s early leaves to be preformed in the new buds.

While we are considering buds and stems, let’s admire some flowers.

Chinese pistache

Norway maple

Buckeye/ horse chestnut

I’ve written about Philadelphia’s tree-named streets for this blog and have seen tree-named streets in Berkeley, but it was a recent Times article that sparked this post. The Times reporter, in walking Flushing, NY, found several streets named for trees: Ash, Beech, Cherry, and Holly. He writes,

The streets’ names, like the stately trees that shade them, are reminders of a horticultural tradition thought to go back to French Huguenots who came to Flushing around the same time as the Quakers, also seeking religious freedom. Lewis and Clark sent plant specimens to the commercial nursery founded here by Robert Prince in 1737.

I did not learn of a similar horticultural tradition in Berkeley, but the Quick Index to the Origin of Berkeley’s Names published by the Berkeley Historical Society provided some information about streets like Pine Avenue in the Elmwood. It was named for the pine tree. As was

Acacia,
Bay Tree Lane,
Cherry Street,
Cypress Street,
Elmwood Ave and Court,
Eucalyptus Path and Road,
Hawthorne Steps and Terrace,
Laurel Street,
Linden Avenue,
Magnolia Street,
Oak Path, Street, and Street Path,
Oak Knoll Path and Terrace,
Palm Court,
Poplar Path and Street,
Redwood Terrace,
Thousand Oaks Blvd,
Walnut Street,
Willow Trail, Walk, and Path, and
Spruce Street.

Pine Avenue is surrounded by other tree-named streets.

Cedar Street was a case of mistaken identity; a cypress was mistaken for a cedar. Encina Place is named after the Spanish word for live oak; Roble Road was named after the Spanish word for oak. Ensenada Avenue, it follows, was named for the “place of many oaks.” Nogales Street, another Spanish derivative, was named because it was the “place where walnuts grow.” Live Oak Park was named for the “multitude of oak trees there.” Oak Knoll Terrace was named for a “particular oak tree” and Pepper Tree Lane was named for the pepper trees that used to line the road.

Fresno is the Spanish word for ash tree, so Fresno Avenue is named for the ash. The Latin term for the genus to which ash species belong is Fraxinus. Although maligned for is shallow root system that lifts sidewalk panels, Arthur Plotnick (in The Urban Tree Book) notes that the ash tree is sacred in Norse mythology - “honey rained and beer flowed” from the ash, also known as the “Tree of Life.”

Easter Sunday found us in Sacramento for the “Treasures from Hearst Castle” exhibit at the California Museum of History, Women and the Arts. I heard of the exhibit on the March 12 broadcast of Forum with Michael Krasny. I especially wanted to see the five-foot replica of the castle’s tiled bath tub. Amanda Meeker, director of exhibitions at the California Museum for History, Women and the Arts, listed this item as one of her favorites in the exhibit. I was disappointed; there was no tub. The replica was simply a swatch of colored tiles embedded in the floor of the exhibit area. Regardless, the artifacts from the castle are incredibly beautiful and diverse in design and origin.

On the way to the museum, we walked through Capitol Park, the 40-acre grounds of the Sacramento Capitol. I noticed markers on the trees labeled with the words “Tree Tour” followed by a number. For example, the Canary Island date palm pictured above (right) is tree #61 on the tour. The Capitol was closed - it was a Sunday and a holiday - so I could not get a copy of the tree tour map. At least I assumed there was a tree tour map. An online search later in the day did not yield a map or mention of a map, but the Sacramento Tree Foundation offers guided tours of the park. There is a weathered, laminated map attached to a concrete block near the Ninth Street entrance. Of the trees identified on the map I was most interested in finding the monkey puzzle tree. I did not find the tree; I became disoriented without a portable map and the intense sunshine was exhausting.

On the streets around the Capitol, I found oak galls (pictured above), ginkgo flowers (below), and sycamores (also below).

I know the tree pictured above is not a London planetree (P. x acerifolia) based on Arthur Plotnik’s description below. (Note that the species name - acerifolia - is composed of the genus name for maple - Acer - and the Latin word for foliage or leaf - folia. The shape of the planetree leaf is similar to that of the maple.) It could be an American sycamore/ western planetree (P. occidentalis) based on Plotnik’s description below, but this specis is not listed on the Sacramento Tree Foundation’s tree list. The tree list contains the California sycamore (Platanus racemosa). Sacramento Tree Foundation is a well-respected urban forestry organization, so I will assume that the tree in the photograph is a California sycamore and that Plotnik’s description is making a distinction between the hybrid London planetree and non-hybrid native sycamores.

Plotnik, in The Urban Tree Book, describes the bark characteristics of sycamores as follows:

The London planetree and its parts are a feast for observers. The tan-gray outer bark, which cannot stretch to keep up with the tree’s growth, peels away (exfoliates) in tubular curls and reveals patches of the smooth inner bark. The colors of this bark vary according to exposure to sunlight and species variety, but the London planetree will usually show a pretty olive green and sometimes a pale yellow among its mottle, even on the trunk. (American sycamores retain more of the flaky outer bark on the trunk {my emphasis}; branches are smoother and show grays, tans, and whites.)

Two BART trains and three buses. This was the route generated by 511.org to get me from Ashby to the Cow Palace, site of this year’s San Francisco Flower & Garden Show. Luck was with me. I took a direct BART to the city, met a friend for a long lunch, then took another direct BART to Balboa Park. At the Balboa station there was a shuttle waiting to transport visitors to the show!

I bought my half-day ticket in advance rather than at the door so I would definitely attend the show. I wanted to see the urban forest garden - “Healthy Communities Grow on Trees” - developed by the USDA Forest Service, California Urban Forests Council, and the Mandeville Garden Company, but I would not have a companion so feared that I would back out at the last minute. In addition to the urban forest garden, I also wanted to see the garden that was the subject of a San Francisco Chronicle series on the show: “Ripples and Rays” by East Bay designers Joy Lung and Christian Ehrhorn of Misty Morning Gardens. (Joy Lung is the sister of a friend).

I saw both gardens and discovered a third: “It Doesn’t Take a Hectare” by Sommersett Designs and Leiber Landscape Services, both of Walnut Creek, pictured above. (Note the hare sculpture by Phillip Glashoff and the play with the word “hectare.") The designers used the same plant palette in four different designs (pictured below). Plants included herbs, lettuces, Meyer lemons, and vegetables like radishes and celery. The marketing material, written by Shelley Somersett, APLD, of Somersett Designs, describes the concept as follows:

It doesn’t take a hectare to feed a family four square
Heirlooms in the Cottage or on an Urban Roof
Wine Country Tuscan or Berkeley “Locavore’
No GMOs are in our food, the nutrients are proof.

Take some dirt, add sunshine, clean water and fresh air,
A designer for the garden and you’re half way there.
When Edibles are planted, sustainable’s the fare.

Breakfast, lunch and dinner your neighbor too can share
The earth still laughs in flowers, the chef’s gourment affair
Feed a hungry neighbor, teach the world to share.

The primary draw for me was the urban forest garden. I have worked as both a community and an urban forester. (There is debate about the definition and scope of the term “urban forest” and thus urban forester; it is more accurate to say I was a street tree manager.) I am very interested in the ecosystem values of designed landscapes and wanted to see the interpretation offered by a major forestry agency like the U.S. Forest Service.

While I was familiar with information provided in the urban forest garden, it was the most uniquely themed garden at the show. The garden was aesthetically pleasing; this is very important to counter lingering misperceptions that ecosystem gardens or landscapes are unattractive. Also, the exhibition was well designed and educative. Numbered signs within the garden highlighted “sound urban forestry concepts.” For example, sign #7 encourages the removal of lawns and replacement with “grass-like species” like dwarf sedge, pictured below. The bench in the photograph was designed by West Coast Arborists using street trees.

Other urban forestry best practices include native plant choices to provide food and habitat for insects, birds, and other animals (sign #4 pictured above, right) and planting larger stature trees to generate environmental benefits like carbon and particulate matter sequestration and storm-water attenuation.

A large stature trees like a coast live oak (Quercus agrifolia) saves 6,010 kilo Watt hours and intercepts 6300 lbs of carbon and 26,900 gallons of stormwater over its lifetime. This compares to 3,270 kWh, 5400 lbs of carbon, 18 lbs of air pollutants, and 14,800 gallons of stormwater for a medium, ornamental tree like an evergreen pear (Pyrus kawakamii). Source: exhibit marketing material.

At the exit I was handed a flyer alerting me to California State Senate Bill SB1527 which proposes to sell the Cow Palace and convert the land to condos and a strip mall. For more information and a petition visit the Save our Cow Palace website.

This post began its life as a short essay about “what’s in a name.” I’ve long been interested in the use of natural elements to name places. Of course, it is ironic in a suburban context where streets and subdivisions are named for plants and animals that no longer inhabit the area, at least not in the numbers they did before development. Anyway, I’ve also been enamored of the large coast live oak at Oakland City Hall and thought the combination of place naming and oak trees would make a good post.

In 1852 the City of Oakland was officially incorporated from Rancho Encinal de San Antonio owned by Anthony Peralta. The translation is ranch of the oak grove of St. Anthony. The men present at incorporation considered An Antonio, Encinal Oak Grove, and Land of the Oaks, before settling on Oakland (Land of the Oaks, James Harlow, 1956).

Pre-incorporation, the Rancho Encinal de San Antonio hosted 900 acres of oak woodland in present day downtown Oakland (dissertation, David J. Nowak, 1991). The woodland had “approximately 1400 trees with fourteen percent tree cover within the stand” (Nowak, 105). According to Nowak, the oak woodland was the second most dominant vegetation type preceded by grass/ shrub/ marshland which covered 98% of the area. The third and fourth most dominant vegetation types were riparian woodlands at 350 acres with 110,000 trees and redwood stands at 175 acres with 13,000 trees. Total tree cover in Rancho Encinal de San Antonio is estimated at 2.3%.

Harlow (1956, 16) notes that Oakland’s “first name might have been Temescal.” The Peralta brothers named the creek that flows through the former ranch Temescal, possibly after sweat lodges (or temescalli) sited along the creek (see Wikipedia entry on the Oakland neighborhood).

Another Bay Area creek is named for something that used to be common along its bank. Strawberry Creek in Berkeley was so named for the strawberries that grew along its bank (Harlow). I wonder if daylighting plans for the creek include replanting strawberries. The option to pick your own fruit at a public creek-park would be another first for Berkeley.

Finally, back in Oakland, the Fruitvale district was named for orchards and fruit farms that were the dominant land use during the nineteenth century.