Street Tree Numbers are Down - and there's a Reason

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The Department of Public Works (DPW) Bureau of Urban Forestry recently announced that the number of street trees removed by the City in 2017 exceeded the number of trees planted - meaning the total number of street trees in San Francisco went down last year. That’s not a big surprise - with the passage of Prop E in 2016 (now called “Street Tree SF”), the City took back responsibility for all street trees in the city, and with a backlog of aging, sick or dead trees, most experts expected there to be an upward blip in removals.

However, there’s another structural reason that tree numbers may continue to decline, which I noticed when DPW tagged a number of trees in my neighborhood of Cole Valley for removal (one of the notices is in the photo to the left). If you look carefully at the notice in the photo, you’ll see that a total of 21 trees were tagged for removal, but (look at the bottom of the flier) only 12 permitted to be replaced. Why? In some cases, the existing trees were too close to underground utilities; in other cases too close to streetlamp poles. In yet other cases the trees were too close to other existing trees. DPW maintains a set of standards for planting street trees, and in some cases these rules have tightened over the years, so a tree basin that was plantable years ago may no longer work today.

What this means is that there is a structural factor that will result in fewer street trees, year after year. DPW’s rules for the placement of street trees are there for a good reason, and I’m not suggesting that they be changed.* However, we need to realize that as we lose street trees in the ordinary course of urban life - from age, or disease, or getting hit by a delivery truck, many of them won’t be replaceable.

What’s the solution? We need to accelerate plantings in places where no trees existed before. And now that the City is in charge of our street trees, that means getting more funding. We all need to push our supervisors for more funding for street tree planting - because if we don’t, you’ll start to see fewer and fewer trees in the neighborhoods.

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* OK, I do have one quibble. The City disallows trees within a few feet of a streetlamp pole - because you don’t want a tree blocking light to the street. But there are plenty of small trees that would work in those spots, and never grow large enough to be a problem. Especially now that DPW controls things (including the species of trees that get planted), I think that’s a rule that could be relaxed.

TransBay Roof Park is SPECTACULAR!

Chilean wine palm (Jubaea chilensis)

Chilean wine palm (Jubaea chilensis)

I got a tour of the park that is the roof of the new Transbay Transit Center last week - Adam Greenspan, the landscape architect who led the design of the park, was kind enough to give me a guided peek at what is about to open to the public this weekend.   It's hard to decide which superlative to use to describe the new park (many would apply), so I'm just going to say that it's *spectacular*.   I had known for some time that the designers of this park were curating interesting species from around the world, but you have to see this place to appreciate what a special amenity is about to be bestowed on San Francisco.  

I will leave it to others to comment on the landscape design of the park - I'll just describe the imagination and deep botanical knowledge that went into the collecting of the trees and plants you'll find here.   Greenspan has largely used trees and plants from Mediterranean regions of the world, taking advantage of plants that will do well in San Francisco's climate.   There are trees from California, of course - California buckeyes, Monterey cypress, and other trees commonly seen in San Francisco, but also a dozen or more California sycamores (Platanus racemosa), a coastal California tree which is almost never seen in San Francisco streets.

As you walk around the perimeter of the park, you come to a Chilean garden (with several monkey puzzles), a South African garden, an Australian garden (with some amazing Brachychitons - both B. acerifolia but also B. rupestris (Queensland bottle tree - with a huge, bulbous trunk), and two separate desert gardens on the west end of the park, with three striking dragon trees (Dracaena draco).

My personal favorite in the garden is a still small wollemi pine (Wollemia nobilis) - the tree that had been thought to have been extinct for hundreds of millions of years - known only from fossil records - until a few dozen of the species were discovered in a ravine near Sydney, Australia.  (Hello, Rec Park Department - we need a lot more of these in San Francisco parks!)  The wollemi pine is located in the roof's "ancient garden", with ginkgos, cycads and other plants that have graced the earth for millions of years.  

monkey puzzle tree (Araucaria araucana)

monkey puzzle tree (Araucaria araucana)

But I think the most spectacular trees in the park are the palms - Greenspan loves palms, and it shows, especially with the majestic Chilean wine palm that is set in a central lawn of the park, not far from pindo palms, some nikau palms (native to New Zealand), various Trachycarpus species (not just our common windmill palm, T. fortunei), a few Brahea species, and on and on and on....  There are probably a dozen palm species here that are rarely or never seen in San Francisco.   

So run, don't walk, to see this park when it opens!   I just hope that we can keep the Transbay Roof Park in the shape it's in now - it's going to take a lot of work to keep this garden looking as good in 10 years as it does now.  I volunteer to be a maintenance docent!   

“Snow in Summer”!

Wow - was biking in Noe Valley today and saw this  amazing tree at 118-120 Jersey Street. We call it flaxleaf paperbark, but not hard to see why it’s called “snow in summer” in its native Australia!  Melaleuca linarifolia is the scientific name; it’s one of the most common species in the Melaleuca genus as San Francisco street trees. 

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118-120 Jersey Street

Madeira Trees

Just got back from a week visiting the island of Madeira - a Portuguese island off the coast of Morocco, just north of the Canary Islands.  About 33 degrees latitude, so about the same as San Diego, and it also has a similar climate - coastal, not too hot, but warm enough to appear semitropical.  It used to be a big producer of sugar cane, and you still see sugar cane growing and being harvested in spots around the island, but the bigger crop now is bananas, which have become a big export crop.  And of course vineyards, for the world-famous madeira wine.

African tulip tree in Funchal's old town

African tulip tree in Funchal's old town

Since the climate is similar to coastal California, I was curious to see what trees were used in Funchal (the capital and largest city - really the only city of any size on the island).   We were lucky to be able to stay at a hotel (Quinta da Casa Branca, if you ever go) that was formerly an estate owned by a guy who was obsessed about tropical trees - the entire 4 acre property was covered with spectacular and unusual tropical and semitropical trees, all of them with identifying plaques with scientific name, common name (in Portuguese and English) and location of origin.   OK, so that might have had something to do with our choice of hotel. 

Once we got out into the city, the most spectacular trees were the African tulip trees (Spathodea campanulata) - all of them in bloom (we were there in early April).  The tree is native to tropical Africa, and not all that well suited to our cooler Bay Area climate - not sure I have ever seen one in the Bay Area.   The trees are amazing in bloom - football-size clusters of intense red-orange trumpet-shaped flowers.   

Laurus novocanariensis - closeup of leaves and flowers

Laurus novocanariensis - closeup of leaves and flowers

We spent one day hiking in out in the country, in the laurel forests of the island (also called laurissilva), a type of forest found in the Atlantic islands of Madeira, the Canaries and the Azores - areas with high humidity and relatively stable, mild temperatures.   This type forest is a remnant of what once covered big parts of Europe before the ice age.  The forest had a species from the Laurus genus (the genus that gives us Laurus nobilis, the sweet bay tree that is used in Mediterranean cooking).  The Madeiran species is Laurus novocanariensis, which is endemic to Madeira and the Canary Islands (meaning it exists only there), and was just recently declared a separate species - it was previously thought to be a variety of Laurus azorica.  Apparently it hasn't been around long enough to develop a common name, so I'll dub it Madeira laurel.  (The hikes in Madeira  are amazing - they typically follow irrigation channels called "levadas" that follow the ridge lines of the mountains and bring water from the wetter northern side of the island to the drier south.)   

Dragon tree - Funchal botanical garden

Dragon tree - Funchal botanical garden

We saw lots of examples of Dracaena draco, the Canary Islands dragon tree.   The tree is native to Madeira (and to the Canary Islands, Cape Verde and western Morocco), but we never saw any in the wild.  They were common in Funchal - perhaps evidence of some local pride in a native tree :-)   Unlike most trees, dragon trees are monocots, related to palms and grasses.  The largest example we saw was in Madeira's botanical garden (a real gem, by the way - not to be missed if you're visiting the island). 

 

 

 

Queensland kauri in Funchal

Queensland kauri in Funchal

One of the big tree-surprises in Funchal was that the city's principal street was Agathis robusta - the Queensland kauri - a tree in the Araucaria family from northern Australia, closely related to Agathis australis, the more famous kauri from New Zealand.   The trees were very erect/fastigiate - perhaps a variety that's been bred for that quality?   I've never seen this species used as a street tree anywhere in the world, but they were very happy in Funchal.  Maybe something to experiment with in similar California conditions?  

 

 

And, of course, there were pride of Madeira (Echium candicans).  They weren't quite in season (surprisingly, since they're in full bloom in San Francisco).

 

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Canary Islands dragon tree - rare sight in SF!

I can't remember seeing one of these before in San Francisco.  My husband took me this past weekend to his new favorite dog park (our dog Mather, named after the San Francisco Sierra camp, needed a run).  It's a flat area in Corona Heights Park that you can access either from State Street or from Flint Street.   (If you're approaching from Flint, walk past the tennis courts; if you came up the driveway from State Street, walk past the basketball courts.)  You'll come to a dog park adjacent to some community garden plots. - and in between the two, this Dracaena draco - the common name is Canary Islands dragon tree.  

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The plant (not really a tree - it's a monocot with a tree-like growth habit) is native to the Canary Islands, Madeira, Cape Verde and western Morocco.  There's a beautiful example of this tree at the Hotel Coronado in San Diego; the two largest  in California are both in the Santa Barbara area - one at the Sotto il Monte Estate in Montesito, and the second at Mount Calvary Monastery behind the Santa Barbara Mission. in Santa Barbara.   But you don't see them often this far north.  I'll actually be in Madeira in two weeks, and will update this with new photos if I see some!

Spring must be here - Acacia baileyana in bloom

Bailey's acacia - southwest corner of Grattan and Shrader Streets in Cole Valley

Bailey's acacia - southwest corner of Grattan and Shrader Streets in Cole Valley

I've been doing a "Cole Valley Tree of the Month" series for some time in the Cole Valley Facebook group, and when I walked by this tree yesterday at the corner of Grattan and Shrader Streets in Cole Valley, I grabbed my iPhone, shot this picture and made it the "Cole Valley tree of January" - only to be reminded that it happened to be the first of February!   It's just that I associate this tree - Bailey's acacia, or Acacia baileyana, with January blooms.   Bailey's acacia is the first tree to bloom in the spring (after 30 years in San Francisco, it still seems weird to me to call January “spring”), and the brilliant yellow flowers are eye-catching. The tree is native to Australia, where it’s called “Cootamundra wattle”, as it's native to Cootamundra, New South Wales, just west of Canberra.  (The town holds a 'Wattle Time' festival every year when the trees start to bloom.)  

Acacias do put out a good amount of pollen, but the pollen is only mildly allergenic, and it's heavy, which means it exists only in the immediate vicinity of the trees.   You're much more likely to suffer allergies from oaks, elms, pines, and and other wind-pollinated trees - the inconspicuous flowers of those trees don't get noticed, but they put out great quantities of lightweight pollen.   Trees with colorful flowers aren't as likely to cause allergic reactions since the pollen is heavy and sticky (it's designed to stick to insect pollinators, who are attracted by the flower's color).     

New Zealand Trip

Monterey cypress north of Auckland, New Zealand

Monterey cypress north of Auckland, New Zealand

Just got back from a 2 week trip to New Zealand - it's been my #1 "bucket list" place for a long time.   I was especially excited to see trees that are San Francisco street trees (New Zealand Christmas trees, giant dracaena, tea trees, etc.) in their native habitat.  

One thing I noticed was LOTS of Monterey cypress (Cupressus macrocarpa) and Monterey pine (Pinus radiata, which the New Zealanders call "Radiata pine") in the countryside, used as windbreaks, shade for sheep and other livestock, accent trees, etc.  Which made big parts of the countryside look a lot like California!  There were also many stands of Monterey pine used used as lumber trees - without any evidence of pine canker that i could see.  

Northern hemisphere conifers (Douglas fir is a prominent example) have become naturalized in big parts of New Zealand, and have become invasive pests, taking over entire landscapes.  Interestingly, our Monterey pine and Monterey cypress are not invasive, because the cones of the tree typically only open and disburse their seeds where there is fire or extremely hot weather.   

New Zealand Christmas tree in the Bay of Islands, New Zealand

New Zealand Christmas tree in the Bay of Islands, New Zealand

I spent three days hiking through native beech forest on the Routeburn Track on the South Island.  It was very cool to see forests composed almost entirely of  different species of Nothofagus (a cousin of our northern hemisphere beeches) because they were so new to me (the only Nothofagus I can remember seeing here in CA was a giant specimen at Filoli, south of San Francisco).  One cool tree I encountered along the way:  the tree fuchsia - Fuchsia excorticata, the world's largest fuchsia, with distinctive papery bark (and recognizable fuchsia flowers).   

Of course, I made a point to find New Zealand Christmas trees (Metrosideros excelsa) on the North Island, although sadly by the time we got there on January 2, they were almost all out of bloom (these native trees seemed to be strict about blooming at Christmas time).   They're called by the Mauri name "Pohutukawa" in New Zealand, and the New Zealanders were very surprised to find that they were popular street trees in San Francisco.  

Aerial roots on a New Zealand Christmas tree in Gisbourne, North Island, New Zealand

Aerial roots on a New Zealand Christmas tree in Gisbourne, North Island, New Zealand

Sadly we didn’t get to see any Nikau palms (New Zealand's only native palm, and one of my favorites of the palms) in their glory - saw a few of them planted as street trees (!) in Whangarei in the north island, and every once in a while saw one in the kauri forest on the west side of the north island.  I was surprised to find that the best places to see them in New Zealand were on the west side of the cooler south island.

It was a great trip - New Zealand is a great place to visit for many reasons, and interesting trees is definitely one of them!    

Ceanothus in bloom

Ceanothus seems to be in bloom all over the city as I write (early April 2017).   There are 50 or so speciesof Ceanothus, but very few that can be trained as a tree.  Ceanothus 'Ray Hartman" is one - it's a hybrid (cross) between two parent species: Ceanothus arboreus from Catalina Island in southern California, and the northern California Ceanothus griseusIt’s the only Ceanothus planted as a street tree in San Francisco, and one of the very few California natives that you’ll see planted in sidewalk cuts on the street (along with Catalina ironwood).  

These trees in Cole Valley at the corner of Waller and Cole are some of the best in San Francisco.

(And I wish I knew who this "Ray Hartman" was/is - doesn't seem to be any info on the web about him.   Let me know if you know!

Corner of Waller Street and Cole Street in San Francisco

Corner of Waller Street and Cole Street in San Francisco

Ceanothus closeup

 

 

Azores Trees

Just got back from a week in the Azores - Sao Miguel and Terceira islands.   The Azores are Portuguese islands in the middle of the Atlantic Ocean - 800 miles west of Portugal, and about 2000 miles east of Boston - volcanic islands, with a mild, San Francisco-like climate (coastal, rarely above 80 degrees fahrenheit, and rarely below 45 degrees).  

New Zealand Christmas tree - Ponta Delgada in Sao Miguel Island, Azores

New Zealand Christmas tree - Ponta Delgada in Sao Miguel Island, Azores

It was interesting to see so many introduced trees in the Azores that are also popular as ornamentals here in San Francisco.   Metrosideros excelsa (New Zealand Christmas tree - see photo above) is often used in the Azores as an ornamental, but it has also naturalized in the forests of the islands (which I’ve never seen here in California).   The New Zealand Christmas tree in the photo above was a huge specimen in Ponta Delgada, the capital city of the Azores - so big that it had supports to hold up its limbs - if you look carefully you'll see the many vertical steel supports.    Trees from the Araucaria genus are everywhere as specimen trees -- especially Norfolk Island Pine trees (Araucaria heterophylla).  (The Norfolk Island Pine in the photo below was a young specimen just outside our hotel window in Angra de Heroismo, the largest city on Terceira Island- the hotel was in an early 1600s stone fort built by the Spanish during a 40 year period when they controlled the islands).   And Pittosporum undulatum (Victorian box) is everywhere as a naturalized tree - to the point where there were forests of the tree - it has become an ecological problem on the islands.

Norfolk Island Pine - Angra de Heroismo on Terceira Island

Norfolk Island Pine - Angra de Heroismo on Terceira Island

There are trees that are native to the Azores - in fact endemic to them (which means that they found in nature only in the Azores).  It was interesting to see native species that were closely related to trees I recognized, but which had developed into separate species as a result of the physical isolation of the islands.  Laurus azorica, for example, was obviously a close relative of the Grecian bay (Laurus nobilis) that is found on San Francisco streets.  

Because the Azores were isolated from Europe and North America for millions of years before the Portuguese arrived in the 1400s, the trees and plants evolved separately from their cousins in Europe and North America - which explains why there are so many unique species here. It also explains why introduced species from elsewhere are such a problem - the introduced species have no natural pests or diseases, and so they can out-compete the natives. Interestingly, Azores plants have been creating ecological troubles on other islands after being introduced - for example, the Azores’ evergreen fire tree (Myrica faya) is the main species to have regenerated on old lava flows in the islands. It was introduced to the Hawaiian islands, where it has threatened local flora there. (By the way, the Azores reminded me of the Hawaii islands with cooler weather - the island groups are both verdant, volcanic and isolated from other land masses.)

London plane trees (Platanus X acerifolia) line the roads everywhere in the Azores.   The trees below were on a back road on Terceira island.

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By the way, I highly recommend a visit to Parque Terra Nostra, a botanical garden near Furnas on San Miguel Island. The buildings here date to the 1700s, when Thomas Hickling, a wealthy Boston trader, built a home and introduced a number of trees and plants from North America. Subsequent generations of Azorean owners expanded the collection. In addition to a garden filled with endemic and native Azorean plants, there are beautiful plants and trees from other Mediterranean and semitropical areas of the globe, including trees from the Araucaria and Metrosideros genera, eucaplytus, redwoods, tree ferns, various palm species, and huge rhododendrons, magnolias, hydrangeas and camellias.

My favorite tree in the garden (and it was a surprise to see it) was a Wollemi pine (Wollemia nobilis). This is a tree botanists thought had been extinct for millions of years (they only knew it from fossil records) - until David Noble, an Australian hiker with some botanical knowledge, noticed some trees in a remote ravine in Wollemi Park, 200 miles from Sydney Australia. He brought some cuttings to scientists in Sydney, who concluded that Noble had discovered a “living fossil” - somehow, the 100 or so trees in that ravine had managed to survive - the last remaining specimens of their species. (Imagine if a hiker in a remote New Guinea valley had discovered a stegosaurus - it was like that for botanists.) Here’s a photo of me, next to the tree in the garden - not that it’s not very big, since no garden in the world has had one of these for more than 25 years!

Wollemi pine in Parque Terra Nostra

Wollemi pine in Parque Terra Nostra

My Favorite Tree

I'm often asked about my favorite tree.  Not the type of tree I love most, but my favorite individual tree in San Francisco.   This tree, at 1221 Stanyan Street in Cole Valley, is my personal #1, and it's in full bloom right now (it's Memorial Day 2016 as I write; I took the photos below yesterday).

Yellow New Zealand Christmas Tree - 1221 Stanyan Street

Yellow New Zealand Christmas Tree - 1221 Stanyan Street

This tree is one of the city’s best specimens of New Zealand Christmas tree (Metrosideros excelsa), popular for its showy red bottlebrush flowers. And, indeed, all of the many hundreds of New Zealand Christmas trees on San Francisco’s streets have red flowers, except for one—at 1221 Stanyan. Every year around this time, that tree pops with spectacular yellow flowers.

How did this tree end up with yellow flowers? The story goes back to Victor Reiter, San Francisco’s most famous plantsman from the 1940s until his death in 1986. In 1940, there was a natural mutation of the species on tiny Motiti Island in the Bay of Plenty in New Zealand, and Reiter was one of the first Californians to obtain a cutting. As the Reiter family lived in several homes in a three-block stretch of Stanyan Street, they planted the curiosity in front of their 1221 Stanyan address—still occupied today by a family member. And more than 70 years later, the tree is thriving. It’s a beautiful mutant with an amazing history and pedigree—and my favorite tree in San Francisco.

Some Spring Flowers

I was out this weekend, and saw some great Springtime flowers - all on Parnassus Avenue near Cole Street.   And all from Australia! Two types of bottlebrush, and a fragrant sweetshade tree.   Enjoy!

Sweet shade (hymenosporum flavum)

Sweet shade (hymenosporum flavum)

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Weeping bottlebrush (callistemon viminalis)

Weeping bottlebrush (callistemon viminalis)

Lemon bottlebrush (Callistemon citrinus)

Lemon bottlebrush (Callistemon citrinus)

Sunnyside Conservatory

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I've known about the Sunnyside Conservatory for some time - it's a Victorian-era conservatory at 236 Monterey Boulevard with a long history - abandoned by its original owners, the lot at one point was so overgrown that a subsequent buyer of the lot had no idea that the conservatory was even there - it had been overgrown by vegetation.   But I also knew that there were some unusual trees on the property, so last weekend I wandered by to check it out.

I found some interesting stuff - one of the city's largest and most mature wine palms (Jubaea chilensis).  On the steps up to Joost Street is a stunning Caracas wiganida (Wigandia urns) - with giant, showy purple flowers - only the 2nd one I've found in San Francisco.   And to the right as you face the conservatory is some kind of Banksia - in the protea family, with unusual yellow flowers.   

Banksia flower

Banksia flower

Chilean wine palm (Jubaea chilensis)

Chilean wine palm (Jubaea chilensis)

Wigandia urens

Wigandia urens

Victorian Box Blooms Out En Masse

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The Victorian box (Pittosporum undulatum) is one of San Francisco's most common trees, and small white flowers of the tree are out all over the city - as usual in late February/early March.   They aren't conspicuous visually, but they have the strongest fragrance of any common tree in San Francisco, and when they emerge en masse, they can fill entire blocks with their orange blossom-like perfume.   It's a smell that I associate strongly with San Francisco, as I've never seen any city that has this tree more densely than SF.   One of my first memories of San Francisco was walking down Hyde Street, preparing to turn on Pine  to walk downtown to my first job, and smelling the Victorian Box trees around the corner before I saw them!

The flowers of this Australian native are followed by groups of small green fruits, which they turn yellowish, then orange, and finally break open dropping a sticky mess on whatever's below.   As a result, the tree has dropped in popularity a bit, with some trying the sweetshade tree (Hymenosporum flavum) instead.   Sweet shade is another Australian tree

Red Flowering Gums at Peak

My brother was in town from upstate New York a couple of weeks ago - his first time here in 25 years.   Like me when I first arrived 30 years ago, he wasn't familiar with California trees - and it was the red flowering gum that most captured his attention.   "What's that tree?", he asked as we passed this specimen, on the north side of 17th street between Cole and Shrader.    I wasn't surprised – the red flowering gum (Corymbia ficifolia) is one of San Francisco’s most striking trees, and the flowers peak in July and August.  The tree has clusters of brilliant red, pink, orange, or white flowers.  It can’t be easily reproduced from cuttings, and when it is reproduced from seed, nature rolls the genetic dice, so the flower color rarely matches that of the parent tree. Large, smooth, and woody seed capsules (which look like the bowl of a pipe) form after the flowers and hang onto the tree for many months, often until the next year’s flowers are in bloom. 

Red gums are well adapted to San Francisco’s climate (the largest red gum in the United States is said to be within San Francisco city limits), and they can be counted on to thrive almost everywhere in the city.  The native range of the red flowering gum is a very small area (approximately 1 square kilometer) in western Australia, southeast of Perth.

Monkey puzzle tree in the Presidio

Excited to see this monkey puzzle tree (Araucaria arcaucana) in the Presidio ≈doing well.   It's between two beautiful Queen Anne Victorians on Presidio Boulevard just west of Funston Avenue.  Monkey puzzles are native to Chile and western Argentina; they're related to other trees in the Auraucaria family, such as Norfolk Island Pine, cook pines, and bunya bunyas.  The origin of the name 'monkey puzzle' derives from its early cultivation in England around 1850, when the species was still very rare in gardens and not widely known.  Sir William Moleswort, the owner of a young specimen at Pencarrow garden near Bodmin in Cornwall, was showing it to some friends, when one of them remarked, "It would puzzle a monkey to climb that".  As the species had no popular name, first 'monkey puzzler', then 'monkey puzzle' stuck.  Very glad to see the Presidio planting interesting trees like this.  (I wish they would plant some Wollemi pines (Wollemia nobilis) (hint, hint!)).  

Monkey puzzle - Presideo