Tree of the Week

Thuja occidentalis.

Some common names are Arborvitae, Eastern Arborvitae, Northern White Cedar.

The above picture is a Thuja I pruned over on Laguna Honda.

They come in many shades of green, yellow, or blue green with differing shapes and sizes. Sometimes the leaves can hang horizontal, vertical, or in waves. They are quite popular in San Francisco, especially in formal gardens. They are often hedged, sculpted, or sheared.

The name Arborvitae means tree of life. Rich in vitamin C, early European settlers and native Americans used it to fight scurvy.
Naturally occurring in Canada and the northern U.S., these shrubs are food for deer, hares, and porcupines. They are preferred building material for log cabins because they are good insulators and resist rot. They are also used as fence posts and siding for boats since they withstand water damage.
Since they naturally occur in both highlands and lowlands. You can find them growing out of rocky cliffs, on a mountain clearing, or in the ecotone (transition space) between a bog and a forest. They like calcium rich soil.
If you want them to thrive in your garden, plant Thuja where they can get full sun. Also keep the soil somewhat moist. Still, don’t over water. Just don’t let the soil get too dry for too long.
These are very hardy trees with few pests.
Thuja are very slow growing. They can get up to 50 feet tall given the right environment, but it may take 50 years. They can live for up to 1000 years.
Here is a photo of a famous, 300 year old Arborvitae in Minnesota, growing on the shore of lake superior. It is sacred to the Ojibwa Indian tribe who named it Manidoo-giizhikens, or Little Cedar Spirit Tree.

Here’s a link to where I got much of my information on the Arborvitae.

Silk Oak and High Voltage

NW corner of Douglass and 24th Street.
Client: Noe Valley Association.
Climbers: me, Marcello, and Sean.
Ground Crew: Kent, Mikey, and Serge.
Common name: Silk-oak (not a true oak).
Botanical name: Gravillea robusta.
Family: proteaceae (yes, the same family as those plants with the crazy, alien like flowers).

Above: a picture of the leaf and flower

Below: a picture of three of the five trees before pruning.

Silk Oaks, Gravellia robusta do not belong under high voltage power lines. They grow to be 60-100 feet (usually only 60 feet). They grow really really fast. There are several examples of topped Gravellia robusta throughout San Fransicso. There is one at 18th and Valencia also under high voltage power lines.

Topping street trees, meanwhile, is illegal. PG&E does it all the time to trees below power lines. I guess they get away with it out of necessity. Many times there are ways of removing branches that encroach on power lines without topping. But this requires a more delicate touch. I have been called upon many times to clean up trees messed up by PG&E.

The best thing to do is plant small trees under power lines.

It’s not just PG&E that tops trees. Business owners do it so that people can have a clearer view of their signage. Apartment owners do it becasuse it is cheaper than paying an arborist. Homeowners do it because they don’t know any better. If you see tree being topped you should report it immediately. Speaking up is the only way to stop our city trees from being destroyed.

How do you identify a topped tree? How do you report the crime? click on the following link:

This was a long hard day of tree trimming. Serge, a powerhouse on the ground, got sick. He went home after a few hours. That left it up to 5 of us to finish the job. It was also incredibly windy after lunch.

A branch knocked over the pedestrian barrier which shattered a 10″x11″ pane of glass in a restaurant window. During lunch I found a company to fix it. It took him 20 minutes to fix it then he tried to charge me $220. Highway robbery.

These trees were in rough shape. The prior topping led to giant vertical suckers, rotten stumps unable to compartmentalize, and elongated lateral growth. There were several signs of branch failure. The goal was to reduce the height, remove rotting stubs and failed systems, and remove long laterals overhanging the street. Of course, we wanted to make them pretty to look at too.

These trees are in a high risk zone. They overhang a bus stop and several busy shops. If a limb were to fall, the stakes would be high.

I think we really pulled it off. Although they don’t look anything like they would in nature, they now have an urban elegance. Most importantly, they are much safer for the public.

tree killers

I got a call from a contractor who was in a panic. His backhoe had damaged the trunk and root system of this poor Monterey Pine. A concerned neighbor had alerted the department of urban forestry. They in turn did an inspection of the work site and determined that the tree was a hazard and must be removed. This contractor wanted me to reinspect the tree and see if there was a possibility that the tree could be saved.
Despite the lean, the damage, the prevalent high winds, and the giant hole in the ground I thought with a some reduction in wind sail the tree would probably make it. I made the contractor promise that the backhoe would be removed immediately. I also said that I would do a more thorough inspection of the roots and clear away the root crown and buried surface roots. If I were to discover large, damaged or cut roots, especially on opposite side of the lean then I would stop work and advise removal. My friends at the Dept of Urban Forestry backed me up as long as the owner would take full liability.
The next day I returned to the site, prepared to excavate and remove some large limbs. The backhoe was still on site and still digging. There was now several more yards of dirt on top of the root zone. The neighbor showed up too. He pointed out exactly how much dirt had been removed. He was very concerned.

Then I looked at the neighbor’s house. And that’s when I realized that the tree actually blocked his view. At this point I am starting to wonder what is really at stake.

I called the contractor. I told him I didn’t want to be in the middle. It seemed that too many people wanted too many different results. I said I wanted to break my ties and that I wouldn’t write a report verifying that the tree could be saved. I didn’t want to be the fall guy. hehehe

He asked if there was anything he could do for me to make me change my mind. Was that a bribe? I told him that next time he should consult an arborist BEFORE he does construction in the vecinity of a large tree.

The Lorax

A few years ago my good friend Frank Eddy planted a Eucalyptus nicholii in front of his house in the Mission. His plan: to make it look like on of the trees from Dr Seuss’s The Lorax. Kinda like a poodle. Kinda surreal.

So we’re doing a little experiment with tree shaping. Fun. Today, step one, we laid out the basic structure: several short lateral limbs, like lion tails. Six months from they should sucker out and we should get a little more poof. They grow very quickly.

Big Buckeye in Back

Georgia called me to say, in her charming New York accent, that her tree needed some care. She lives with her family on the top of Duncan Street, above Noe Valley. The street is pretty bare except for a few, young trees planted in the last few years by the Friends of the Urban Forest ( What a surprise! In her back yard was this giant California Buckeye, Aesculus californica. As you can see from the picture, it takes up the entire back yard.

Well, Georgia wanted me to raise the canopy so that she could walk under the tree. I suggested that we remove the Bay Tree on the right since it is a distraction. But the Bay Tree started growing at the same time she was pregnant with her daughter. She wanted to keep it for sentimental reasons. That’s the most wonderful reason to love a tree. So instead we decided just to give it a trim.

The main reason why Georgia called me was to remove the lower branches that over hung the neighbors property in the back. They nicely complained about the leaves in the their yard. The neighbor to the left, however, was a different story. She instructed me not to listen to her at all. “If she wants anything she can come talk to me herself!” As you can see from the above picture, Lefty took a big chunk out of the tree.

Fortunately we were able to restore the tree’s natural dome.

Fun Fact: the California Buckeye loses its leaved in the summer, not the fall. This is a survival technique so that the tree can make it though the dry season. Without all the leaves the tree can withstand summer drought. Georgia says that usually by now all the leaves are gone. But since we’ve had such a rainy spring the tree still has all of its leaves. If you look closely you can see some of the leaves beginning to change color.

Olive Tree in the Marina District

Today’s goal: natural flow pruning and shaping. The client wanted to have a more refined looking tree, not so wild as olives like to grow. So we managed to give it shape while still keeping some of the natural, wild olive feel.

We spent a lot of time cleaning up stubs left over by the last tree pruner. Stubs left on a tree from pruning are unhealthy for the tree. It takes a lot longer and a lot more energy to heal these wounds. A proper cut heals much faster. The faster a tree heals its wounds, the better chances it has defending itself against disease entering through the wound.

Many professional tree trimmers leave stubs because it takes longer and is more difficult to make proper cuts. Time is money. Proper tree care is a good investment. My clients care about the health of their trees. They want their trees to last so that future generations can benefit from them as well.

We started getting rained on at the end of the day. I love these spring storms.

Pollarding in March?

That’s me, where I like to be, happy in a tree.

Yeah, okay, it’s a little late to be pollarding. Normally we pollard in the winter, after the trees lose their leaves. That way you don’t have to look at the funny, leafless shoots all winter long.

A little comparison. . .

Trees Company pruned the tree on the left, not the one on the right. The people who own the tree on the right decided to hire the lowest bidder instead of Trees Company which charged more for its quality workmanship.. Both trees were the same species, same age, same size and pruned within a few weeks of each other. Both are Lophostemon confertus located on 18th street in the Castro.

You be the judge. . .

Ficus, Podocarpus

Today Fetter and I worked on a couple of Ficus microcarpa and a Podocarpus gracilior.

Let’s start with the Ficus trees. The goal was to do light, natural flow pruning. We want these trees to grow big, but look natural. As you can see it doesn’t look like we did much at all. I like it when you look at one of my trees and you wouldn’t know that it had just been pruned.

These are fairly young Ficus street trees. It’s my guess that they have been in the ground for no more than 5 years.

You don’t see many young Ficus trees here in SF. Back in the 80’s Ficus were all the rage because they adapt to our harsh urban conditions. 10 years later San Franciscans found out that they rip up sidewalks. So they don’t plant them much any more, except in Pacific Heights. Your guess is as good as mine. . .

Back in 1990-91 there was a freak cold spell here that wiped out thousands of Ficus trees. There are still many in the Mission, especially along 24th Street where the weather is about 10 degrees warmer than the rest of the city.

The fruit and reproduction systems of species in the genus Ficus are unique. Each species of Ficus has an associated species of agaonid wasp. Ficus species can only be pollinated by their
associated agaonid wasps and in turn, the wasps can only lay eggs within their associated
Ficus fruit.

The Ficus is everywhere. It is a terrible nuisance in parts of the world where the pollinator wasp has appeared. In Hawaii, Florida, Bermuda, and South and Central America it is an invasive weed. Animals and birds spread the seeds everywhere. They often grow epiphytically, starting off as a seed dropped in the crotch of another tree. They will eventually choke out the native host tree.

The images below are the before and after pictures of the Podocarpus gracilior.

Laurel, Eugenia

The priority was to prune the tall Eugenias away from the neighbor’s windows and make them shorter. The Laurel, meanwhile, had some dead branches and was messy. It needed some layering and some shape.

Laurel? Prunus laurocerasus.
What’s in a name?
Prunus, means plum. It’s the same genus as the plum, apricot, cherry, and almond.
Lauro means “laurel” and cerasus means “cherry.” Which is why it is commonly called the Cherry Laurel.

Often used as a hedge. Sometimes used for MURDER.
see below:

The Cherry Laurel, unlike its tasty fruiting cousins, is poisonous, though it smells like almonds. It used to be used to flavor milk. After too many accidents with children this practice ended.