CMGH (California Master Gardener Handbook) is the text we used for our introduction to horticulture class, OH50, here at City College of San Francisco. This is an addendum to Chapter 12: Woody Landscape Plants.

Usually in this chapter we focus on trees, since they are one of the main woody plants. Trees are a big industry. Forests, lumber, construction, and many wood products are all dependent on trees. In horticulture, our primary work with regards to trees is planting, pruning, and taking out trees. In city agencies, there are urban foresters who work on the tree canopies. All around town, there are companies, large and small, that do the same work. You must have seen them with their boxy trucks towing a chipper behind them. Some are fine pruners that specialize in being a sculptor of living trees; they use only hand tools and charge top dollar. Some tree workers specialize in pruning trees around power lines – utility arborists – they need to be extra aware since that high voltage has been known to jump ten feet from the line to the worker down to the earth. There are also people that will chunk out that 200 foot tall Monterey pine in your back yard because it has been dropping huge branches on the neighbors roofs. And there are people skilled in the diagnosis of tree diseases, or folks that consult with regards to trees in a dispute.

The go to organization for certification and training is the ISA, International Society for Arboriculture. Just to go back in time a little bit, bout twenty or thirty years ago. Back in the day, it seemed all you needed to work as a tree worker was a pick up truck and a chainsaw. Tree workers were called tree-toppers. Topping is the practice of cutting off the head of a tree, a woody stem of a leader that is usually say three four five years old. Topping was a common method to bring the height back down, to clear a view, or keep a tree short. Also, old times, you would cut a limb flush to the trunk, cause it was thought to look neater and better. Then, you would paint over the wound with a seal of some kind, a goopy rubber or tar compound as a bandage. Another thing – people didn’t think you could really hurt trees that much, so to climb them and prune them, they would wear these tree climbing spurs or spikes to jab into the tree and shimmy up and down the trunk. What else. The folks that worked in trees were pretty beefy looking, the men and the women. They looked like heavy weight fighters or viking warriors. Folks who would keep a fire lit around hearth twenty four hours a day while they sharpened their blades, partied like wild animals, and looked forward to another day of battle with 50 ton creatures.

Tree work was, and is, hard physical work. It ranks right up there with commercial fishermen for rates of injury and disability. In part, like floating around in the sea, you are dealing with mother nature, who is unpredictable and does not always follow any set rule. Yes theres physics involved; yes probability and experience comes into play. But, you are never 100% sure, and therein is the challenge as well as the difficulty.

One of the major turning points comes to us from a doctor Alex Shigo, a tree pathologist, tree surgeon and biologist with the US Forest Service. He cut trees lengthwise, slabbed em, and started to reveal for us the inner workings of trees. We started to see how rot started after we topped and wounded trees, and how covering up the wounds with goop just trapped the moisture and caused more problems down the line, not less. We began to see trees as living beings, not just as decoration for cities or board feet of lumber. As a result, the whole field of arboriculture started to grow, and has become a respectable science in and of itself today. And the field workers – some still look like they could strangle a bison with their bare hands, but many of them look more like fit rock climbers or triathletes now. They use the same carabiners, ropes, ascenders and the like, and no longer use climbing spurs of loggers of yesteryear. They traded a bit of that brawn for skill and technology.

If you want to work in the trees, it is best to go and work/apprentice with an established tree company, large or small . You will likely start as a grounds person. If you are not afraid of heights and are willing to work, then they will stick up in the trees. Perhaps in time, you will graduate from the trees to be a manager or foreman and go do bids instead of sawing and chipping and macheteing all day long. But I know you will still miss being in the trees because that is the funnest part of all of it. And watching stuff you cut drop, that is fun too. Occasionally, there are also apprentice opportunities with the municipal tree workers. Like any trade, you will learn as you go, reading and books can only take you so far. While working, try to stay healthy and avoid injury, know you body mechanics.

Another way to jump into the field around here is to go and intern or volunteer with the Friends of the Urban Forest. They can get you started planting and caring for street trees around the city, and learning the local species.

Now, as an addendum to chapter 12 Woody Plants in California Master Gardener Handbook, here is a smattering of add ons to various topics covered in the text. Topics in italics.

Selecting plants in the nursery (308)

Do you buy plants big or small? What is better? A five gallon or a fifteen gallon can? This is a tricky question to answer. Unlike a kitchen cabinet or a walnut table, a plant is gonna grow. If it is happy it will grow great, it not happy it will just sit there or die. Same lesson – right plant right place. Say you buy a 24” box Magnolia ‘Vulcan’. Cost you $600. But you plant it in the wind, out in the open. Plenty of water and irrigation and fertilizer but… It just sits for five years, sorta blooms but real sad like, leaves all blotched and in pain. Not doing well. Another example: you buy a little four inch box of a plant – hollyhocks. Put it in a warm sunny place, and in a few months it is like six feet tall with tons of flowers! Last one: You want a nice screen of greenery to block the neighbors view. The nursery convinces you to buy 10 – fifteen gallon Podocarpus fern pines. You line em up real close to one another, spaced like two feet apart from one another. First three years, wow they are really great. Then they become this massive messy dense forest filled with black sooty mold (cause all crowded no air flow), and you have to have these gardeners come by a couple times a year with huge tall ladders to prune them into boxy rectangles. You are thinking – should I have gotten smaller plants? Spaced em out more? Then you decide to rip em all out and start over…

Roots (309)

If a plant has been sitting too long in the container it may have roots that come out of its container drain holes and stick into the ground. You will likely have to cut those off to get it out of the pot. Also, the roots can swell up and jam tight the plastic pot, at which point you have no choice but to cut the plastic pot itself to remove the specimen. Be careful of the sharp edges of cut plastic. Friends of the Urban Forest initially did not ever prune the roots of the trees they planted. What happened then over time was that the tree roots were forever stuck in that same ‘goin in a circle’ pattern. So the roots would never anchor strong into the local native parent soil, and the trees would fall over in the wind storm. It takes a bit of drastic measure of root pruning to free the jailed & self destructive roots and allow it to be free. But it is necessary and worthwhile for longterm tree health.

Pruning (314)

Here is another tricky one. Now it is generally recognized that topping is not good for a tree. In San Francisco you can actually be fined for it; it is technically illegal to do. The fine is around eight or nine hundred dollars per tree. But what about the pollarded trees? Pollarded? Whats that? Well go to Civic Center, or the bandshell concourse in Golden Gate Park, and you will see these trees all knobby. They are sycamore and elms. In some parts of the city Eucalyptus are also pollarded. Pollarding is a particular style of pruning that is done yearly after the leaves fall; it keeps trees at a uniform height and regular appearance. So then how do you start a pollarding process? Well you have to top the trees to get them to grow that knob and stay the same. But isn’t topping wrong and illegal? Well yes but in some trees that is okay and there is an exception…Wait what? Say that again? And so on and so forth. Tree politics.

Palms for California (333)

You can see about 80% of the palms on this list in various places around town.
The Brahea and Caryota fishtails are in the new Celebration garden at the San Francisco Botanical Garden.
There is a Butia, maybe more, also in SFBG up way back in the cactus and succulent garden. You will not miss its enormous form and stature.
Chamaedoreas are the common common indoor palm you can see at any nursery’s indoor plant section.
Chamaerops is the Mediterranean fan palm. In nature it is so short statured that you cannot see its trunk, its all below ground. They like to talk about how it is one of the most cold tolerant palms and hence they planted them on Sloat right across from the zoo. They are surviving but with all that salt spray and wind do not look their best.
Dypsis is one of the palms on the sides of the entrance to the California Academy of Sciences.
Phoenix canariensis is in front of the DeYoung, all along Market Street, on the bay bridge, etc.
Phoenix dactylifera is a skinner version of P. canariensis found on Dolores Street. This is the classic date palm of the desert and commerce.
Phenix roebelinii is a multi trunked little palm you always see downtown in a container at the entrance to fancy hotels.
Rhapis is another fan leaved indoor palm you will find in the indoor plant section of nurseries. It is also in SFBG behind the bathrooms by the main lawn. Planted in the protected shade.
Syagrus is a commonly planted palm throughout the city. it is on the plaza between our CCSF biology department and cloud hall.
Trachycarpus palm is the palm with a furry hairy trunk. It is planted all along Monterey Boulevard by CCSF.
Washingtonia is the tall tall lanky palm in the mission. On Mission Street. Also planted at SOMA recreation center. The two species – one is thicker, and more robust, the other skinnier.