Most shrubs and many perennials get larger than the diminutive mugo pine, Pinus mugo. The most common type grows very slowly as a dense and rounded mound only a few feet tall and maybe twice as wide. Only a very old specimen might reach an eave. The paired dark green needles are about one or two inches long. The symmetrical brown cones are a bit shorter. Mugo pine is also known as Swiss mountain pine and because of a misprint in the eighteenth century, mugho pine. Although native to mountains in Europe, mugo pine is most popular in Japanese gardens and for bonsai. Because it grows so slowly, it can be happy in planters and large pots. In large urns of regularly changed flowering annuals, it can be a nice permanent and evergreen centerpiece.
For spacious landscapes, Canary Island pine, Pinus canariensis, became more common than Monterey pine through the 1970s. New trees became less popular as old trees demonstrated how big they get! However, as seemingly docile live Christmas trees, they still often sneak into gardens that are not big enough for them. Their short blue juvenile needles suggest that they stay small.
They instead get quite tall. Old trees can get more than a hundred feet tall, even if their canopy gets no wider than twenty feet. Their rich brown bark is distinctively and coarsely textured. Their thin and long needles are somewhat pendulous, with a rather fluffy appearance. They are in bundles of three. Although individual trees are not very broad, their shade can get too dark for other plants.
Canary Island pine is a stately tree, but is not easy to accommodate. It produces copious foliar debris that can shade out lawn and ground cover, and accumulate on shrubbery. In unrefined areas, without other plants, foliar debris suppresses weeds. However, too much can be combustible. Such grand and resilient trees suit parks, and are ideal for freeway embankments and interchanges.
From coastal regions around the Mediterranean Sea, the Aleppo pine, Pinus halepensis, came to be right at home on and near the coast of California. Once established, it can survive quite happily on rainfall. Trees that get too much water can actually get too heavy with foliage, and may eventually get disfigured if limbs break.
Shade under an Aleppo pine is not too dark. The light and sometimes yellowish green foliage is rather wispy, comprised of thin paired needles that are about three inches long. The sculptural trunks almost always lean to one direction or another, and often divide into multiple trunks once they grow out of reach. Bark is light gray with light brown striations.
Young trees can get big rather fast. They tend to be somewhat conical, or at least upright, until they get to be about forty feet tall. Then, they tend to shed lower stems and develop irregular branch structure with rounded tops as their growth rate slows. Only a few old trees in ideal situations slowly get to seventy feet tall. Seedlings sometimes appear where they are not wanted.
Even though it can get about fifty feet tall and wide, Italian stone pine, Pinus pinea, often gets planted as a small living Christmas tree into confined urban gardens. It gets so big so fast that it can get to be a serious problem, as well as expensive to remove, before anyone notices. It is really only proportionate to large public spaces such as parks or medians for big boulevards. The bulky trunks typically lean one way or another. The long limbs spread laterally to form an unusually broad and flat-topped canopy.
The paired needles are about four to six inches long. However, small living Christmas trees are still outfitted with juvenile foliage that looks nothing like adult foliage. Juvenile needles are single, very glaucous (bluish) and only about an inch or an inch and a half long. Adult foliage may not develop for a few years. The four or five inch long cones mature slowly for three years. Squirrels and birds like the big seeds, which would otherwise be known as pine-nuts if people could get them first.
(Apologies for this inadequate illustration of Italian stone pines damaged by traffic. It was the only picture of Italian stone pine I could find.)
By modern standards, the public schools that I attended in the early 1970s would be considered to be bleak and primitive. The building were utilitarian and simple, from about twenty years earlier. The landscaping was comparably simple, with a big lawn and proportionately big shade trees. A screen of alternating Monterey pine and Monterey cypress was hedged on the southern half of the eastern boundary of the schoolyard. The only deviants to the simplicity were a few significantly older trees on the northern half of the eastern boundary of the school yard. There were two coastal redwoods, a Canary Island date palm, a cedar, and a spruce of some sort. They were all quite mature, and were likely remnants from an old farmhouse that was there before. Perhaps they wanted us to be aware that everything changes.
On the way to kindergarten, back when children were allowed to walk to school, I weaseled my way underneath the first Monterey pine and Monterey cypress on the southern end of the fence line, and fell asleep. I do not remember how long I stayed there, but it was long enough to get in serious trouble with my very worried kindergarten teacher. After that, I could only visit those two trees in passing, and perhaps stop only briefly to smell the foliage or shake some of the rain away.
Nearly four decades later, but only a few years ago, I was assigned the grim task of composing the arborist report that would justify the issuance of a permit to remove that same Monterey pine, which was the last that remained of the hedged trees that I remember. I did not know that when I went to the site. I was just told that it was a ‘pine’.
Visiting the old school was not a pleasant experience. The entire site was surrounded with a prison like fence and saran screens to obscure the view inside and out. There were no open gates. I needed to be escorted to the tree by a professional chaperone. Much of the schoolyard had been very synthetically landscaped with microtrees and pretty flowering shrubbery that was intended to impress parents rather than appeal to children. It is bad enough that there are no orchards or open spaces remaining in the region, but it is worse that children are deprived of the open lawns and trees and natural spaces that my generation had taken for granted on the grounds of our school. Are children even allowed to climb trees anymore? Do they know what dirt is? Can they observe a chrysalis split open to reveal a new butterfly before the gardeners shear the shrubbery and take the learning experience away? It was saddening.
Once I realized that the tree that I was expected to condemn was my old friend, I asked the chaperone, who seemed to know a bit about facilities at the site, why anyone would want the now mature tree to be removed. I knew that it had been mutilated while young, but was impressed with how it somehow recovered and developed a well structured trunk. I thought that perhaps someone noticed something that I was missing in my inspection. People who are not arborists are sometimes alarmed by something that is perfectly normal for a tree, such as furrowed bark, or slight seasonal foliar discoloration.
The chaperone explained that the tree needed to be removed simply because it did not conform to the style of the rest of the landscape. I waited for the rest of the answer, but that was it. The tree did not conform.
Nothing gave me more pleasure than to explain that after my evaluation of the health, stability and structural integrity of the subject, I could find no justification for removal.
I was dismissed.
Yes, it was worth it.
However, I knew that for the right price, another arborist would be pleased to condemn the tree. The picture of what remains suggests that the arborist who did so was not even professional enough to get his crew to finish the job. How does this dead stump conform to the rest of the landscape?
Those old trees, the redwoods, palm, cedar and spruce, were right. Everything changes.
The Monterey pine that would not conform is gone now, but it was right too.
Relative to other pines and evergreens that are commonly grown as living Christmas trees, the uncommon and even rare Austrian pine, Pinus nigra, would be a better option. If it gets planted too close to the home, as Christmas trees often do, it does not get big enough to cause major problems. Although much bigger in the wild, local trees may take decades to reach second story eaves.
The species is divided into two subspecie, which are each divided into three regional varieties, which is a fancy way of saying that individual trees may have distinct personalities. Generally, they resemble Japanese black pine, with similar irregular branch structure, but are more dense, and may get a few pendulous stems with age. The dark green needles are slightly shorter and stouter.
The Austrian pine was likely named as such when much of its natural range was still within the Austro-Hungarian Empire, which has since been subdivided into the countries east of the Adriatic Sea. Other larger parts of the range are in Turkey and Spain. Only a small colony lives within Austria, west of Vienna. Austrian pine likes full sun and warmth like it would get naturally back home.
Fire is part of life here. It is a risk that those of us who live in the Santa Cruz Mountains must accept. We live in forests full of abundant vegetation fuel, where fire crews and equipment have limited access. The horrible Tubbs Fire that recently burned an urban neighborhood in Santa Rosa demonstrates how destructive, risky and unpredictable fires can be. That neighborhood was in town, outside of forests, where fire is not such a commonly accepted risk.
This morning, October 17, on the anniversary of the Loma Prieta Earthquake, our community woke to a fire of our own. The sunrise looked more like a colorful sunset, with orange and tan smoke everywhere. The ash that had fallen from the sky made it seem like there had been a cremation party last night. It is getting to look like Pompeii around here. The fire started last night as a house fire near Bear Creek Road outside of Boulder Creek, and moved into more than a hundred acres of forest. Crews from as far away as San Jose responded quickly, and seem to be containing it. The region was evacuated, and Bear Creek Road was temporarily closed. The fire is only 5% contained as I write this before noon. Fortunately, the humidity is up, and the temperature is down.
Fire is more than a part of life for us. It is part of nature. Although almost all fires here are caused by human activity now, fires had been burning forests and wildlands long before humans arrived. There certainly were not as many fires, but without anyone here to suppress them, they burned much larger areas for much more time. A fire started by lightning early in summer could burn for hundreds of miles until extinguished by a storm the following autumn. A single such fire could easily burn more area than all unnatural fires now burn each year. There were likely several such fires annually. That is why old photographs show that California was historically not as densely forested as it is now. Forests simply burned more regularly.
Many plant species know how to work with fire. A few, such as the giant redwood and coastal redwood, survive fire by being relatively noncombustible. They only burn if other vegetation around them gets extremely hot. Most of the pines do not mind burning because their cones open to disperse seed after getting cooked by fire. The seed germinate quickly the following winter to reforest the area that was just cleared by fire. If they are fortunate, they grow up and dominate the forest before other vegetation does, only to burn again a few decades later.
Then there are a few plants that take this technique a step further. Monterey pine is innately sloppy. By that, I mean that it holds much of its old dead limbs instead of shedding them. Lower limbs collect significant volumes of fallen needles, instead of letting the needles fall to the forest floor. Consequently, when a Monterey pine forest burns, it gets hot enough to incinerate competing vegetation and its seeds. Monterey pine cones do not burn completely. They insulate the seeds within just long enough to survive the quick and hot fire, and then open afterward to disperse seed. This is a significant advantage to the Monterey pine, even though they get incinerated too. Not much more than their own seed survives to dominate the forest.
California fan palms (and the related Mexican fan palms) collect long and very combustible beards of dead fronds. When they burn, they likewise incinerate everything below them. The single terminal buds of the palm trees remain safely insulated inside their thick trunks, and will regenerate later as if nothing every happened.
This tactic sounds violent, but it works for the trees that use it. However, enhanced combustibility is not such an asset in home gardens. That is why it is so important to either plant combustible plants at a distance from homes and buildings, or to maintain them so that they are not allowed to collect fuel.
If palms are allowed to wear their beards long enough to reach the ground, other combustible plants should not be allowed to get too overgrown around them. Alternatively, palms can be allowed to wear long beards if the lower portions are pruned up and away from other combustible plants.
Just like there are several plants that are not notably combustible, there are some that are notably combustible. Pines, cypresses, firs, spruces, cedars, junipers, acacias and eucalypti, although useful and appealing in the right situations, all happen to be notably combustible.