Memorial Tree Update – March 22, 2020

Memorial Tree – Before

Updates get complicated as they link back to previous updates to previous updates to previous updates and so on. Linking and reblogging from another blog adds more complication. The last update for the Memorial Tree was reblogged from Felton League on August 10. It and previous updates should link back to preceding updates chronologically. At least it sounds simple.

Another brief update that will reblog here from Felton League at noon will describe more of the social significance of the Memorial Tree rather than horticultural concerns. It really is special.

This little Memorial Tree has certainly been through some difficult times. Despite reassurances that it would not happen again, and that the tree would be outfitted with an ‘approved’ trunk guard, the trunk base has been gouged by weed whackers on more occasions than I can remember. That is an unfortunate consequence of efficient but unaware community service workers.

Such major damage severely inhibited growth. As it begins its fifth year, the Memorial Tree is barely six feet tall. By now, it should be developing branch structure above minimal clearance. Fortunately, it was quite healthy last year. If it continues to grow similarly this year, it will grow above six feet, where it can later develop scaffold limbs. I intend to apply fertilizer regularly.

Stubble had been left on the trunk to enhance caliper growth. That which was developing into significant branches was removed to concentrate resources into vertical trunk growth. Stubble that remains is minimal, but should be substantial enough by winter to get mostly pruned away again. It will more likely be unnecessary, and pruned away completely from the main trunk.

Binding is unfortunately still necessary. The species innately develops irregular form. Binding straightens the otherwise curved trunk. Once the trunk lignifies in the desired position, binding and the associated stake will not be necessary. The larger lodgepole stake holds the binding stake vertical, but is more important for protection from those who bump into the still small tree.

Weeds were removed from around the base of the Memorial Tree, so that there would be no need for a dreaded weed whacker to get close to it. Former damage is compartmentalizing well.

Memorial Tree – After

Grande Finale

They still bloom spectacularly.

This is the third spring that I got picture of this pair of flowering cherry trees in bloom. I took several pictures last year, ranging from closeup pictures of the flowers, to pictures taken from a distance like the picture above. Fewer pictures were taken during the previous spring of 2018, before these trees were groomed of copious necrosis. Sadly, this picture will be one of the last.

The trees will be cut down this year. They stayed just long enough to bloom this one last season, but will not likely be here much longer. They are deteriorating at such a rate that if I were to prune the necrosis away after bloom, there would not be much remaining. The tree to the right in this picture would be only a rotten stump with a few limber twigs protruding from the top.

Structural integrity has been so compromised by decay that, even without the weight of all the limbs that have been pruned back during the past many years, the trunks could easily break off at the ground. When I remove them, I will likely just push the tree to the right over without cutting it first. If there were any branches left, a kid could knock it over by trying to climb it.

As much as I would prefer for these trees to last much longer, I want to install their replacements as soon as possible. Planting them this spring would give them all summer to disperse roots and grow a little bit before blooming next spring. I know they will not be much to look at for a few years, but many years from now, they might be as spectacular as these two originals were.

Regardless, it will be a saddening task to cut down these distinguished trees.


It really looks like something erupted from within!

That was a scary movie back when horror movies really were scary! The first appearance of the baby alien was the creepiest part and one of the scariest scenes! It is too disturbing and gory to describe here. Those who have seen it may have noticed how it might seem to be weirdly relevant to the cavity that opened in the rotting trunk of this deteriorating flowering cherry tree.

With a bit more distance, the rotting trunk looks sort of like an associate of ‘H. R. Pufnstuf’ after an interaction with a baby alien. If you can remember who H. R. Pufnstuf was, you probably shouldn’t. He starred in his own television show for children on Saturday morning in the 1970s. It was disturbingly weird and perhaps even inappropriate for the children it was intended for.

So, it is both rotten and unsightly.

With even more distance, it is obvious that this is nothing to joke about. This is one of two flowering cherry trees that I have been so protective of, and put so much work into temporarily salvaging. Both should have been removed and replaced years ago. This project was scheduled for after bloom in 2018, postponed until after bloom in 2019, and has yet to be done even now.

The problem is that these trees are so popular and so appreciated by the Community. They have been here in the most prominent spot in the neighborhood for several decades. There are not many who remember when the trees were young. No one seems to remember before the trees were here. They are as historical as the older buildings. I can not bear to cut them down.

As you can see, there is no choice now, at least for this particular tree. It is already so decayed that it can barely support its own weight.

As pretty as the bloom is, the disfigured branch structure and trunk are no longer appealing.

Norwegian Wood

Isn’t it good?

This is really getting to be a problem. Too many feral plants that we find at work get canned as if they will eventually be installed back into a landscape somewhere. The small nursery where they recover until their relocation is getting crowded. Although many are practical and appropriate for such recycling within the landscapes here, some are not, so may be with us for a while.

Five feral Norway maple saplings were found in one of the landscapes where mature trees were pruned for clearance from a roof. We could not just leave them there. They eventually would have been overwhelmed by the rest of the forest, or grown too close to the same roof that we pruned other trees away from. They were very easily dug, so came back to the nursery with us.

It was too late to prune them as necessary. They are tall and lanky trunks, with too many comparably lanky branches. As much as I am instinctively compelled to prune them while they are bare and dormant, I will refrain until later in spring or summer, when they will not bleed so much. They look ridiculous. They seem happy though. Their buds are beginning to swell already.

We have no idea where they will go from here. After pruning, they should develop into exemplary specimens. As goofy as they are now, their trunks are remarkably straight. I happen to be fond of Norway maple, and would be pleased to find an application for them here. The problems is that there are too many trees here, and the forests and landscapes continue to make more!

Horticulture in a forest can be like that. It seems like there is plenty of space out there, but so much of the space is too shaded or too crowded.

Blow Out

Wind is messy!

While strong Santa Anna Winds were blowing through Los Angeles four hundred miles to the south, and Storm Ciara was arriving in Scotland and Norway, we were getting some remarkably strong winds of our own. They were not nearly as strong as winds that were causing so much damage in Europe, and involved no flooding rain, but they were dangerously messy nonetheless.

We live and work among dense forests of coastal redwood, the tallest tree species in the World. Beyond the upper edge of the redwood forests are more forests of huge Ponderosa pine. Huge Douglas fir are mixed throughout. Their understory includes trees that would be considered to be massive anywhere else, such as coast live oak, tanoak, Shreve oak, bay laurel and madrone.

Such big trees drop big limb, and in abundance. Furthermore, limbs that fall from such great heights are significantly more dangerous than those that fall from smaller trees that are closer to the ground. They gather major inertia on the way down. They do not necessarily fall straight down either, but can get blown significant distances to where falling limbs may not be expected.

While the winds were blowing through, I could hear crashing of falling limbs and entire trees from the mostly deciduous riparian forest outside. I know that many of the big cottonwoods, box elders, willows, alders and sycamores are deteriorating, but did not expect so many to be blown down while bare. I suspected damage would be worse among the bigger and evergreen trees.

The pile to the left in the picture above is just the debris that was collected last Monday (while I was conveniently not here to help). It is more spread out but at least twice as voluminous as the pile on the right, which is pruning debris that took me several days prior to the wind to collect. The green cargo containers in the background demonstrate how big the piles of debris are.

More debris was collected on Tuesday (while I was still doing other work). The mess was not the worst of it. The roofs of a few buildings were impaled by falling limbs. Some of the damage is significant. Fortunately, the only big trees that fell did so into forested areas where there are no buildings, and electrical service was disrupted for less than a day. No injuries were reported.

Deciduous Fruit Trees Need Pruning

Dormant fruit trees will bloom soon.

Deciduous fruit trees have no business in a low maintenance landscape. They need as much specialized pruning while dormant in winter as roses need, and on a much larger scale. Neglected trees get disfigured by the weight of their own fruit. Disease proliferates in their thicket growth that develops without pruning. Overgrown trees produce most of their fruit where no one can easily reach it. Fruit that can not be harvested attracts rodents.

Of course, deciduous fruit trees are certainly worth growing if they get the specialized pruning that they need. Pruning concentrates resources so fewer but better fruits develop. Fruit bearing stems are better structured to support the weight of their fruit, and lower so that the fruit is easier to reach. Pruning also promotes more vigorous growth, which is less susceptible to disease and insects.

Now that it is February, and the weather has been unusually warm, deciduous fruit trees that have not yet been pruned will need to be pruned very soon. They will be sensitive to such major pruning once they start to bloom. The pruning is too specialized to explain here in just a few sentences. Fortunately, Sunset publishes an very detailed book about “Fruit Tree Pruning” that explains how to prune each of the different fruit trees. Pruning will be more extensive each year as trees grow, but also becomes more familiar.

Stone fruits like apricots, plums, prunes, nectarines and peaches (that have hard seeds known as stones), need the most severe pruning. Their fruit develops on stems that grew last year. These stems should get cut short enough to support the weight of the fruit expected to develop next year. The ‘four Ds’, which are dead, dying, damaged and diseased stems, should get pruned out as well. Cherries and almonds do not get pruned as much because their fruit is so lightweight; and out-of-reach almonds simply get shaken down anyway.

Apples and pears are pomme fruits that need similar pruning, but also produce on stunted ‘spur’ stems that should not be pruned away. Spurs may continue to be productive for many years. Figs, persimmons, pomegranates, mulberries and grapevines all need their own specialized styles of pruning.

California Sycamore

California sycamore is a stately native.

California sycamore, Platanus racemosa, is a riparian species that wants to be a chaparral species. It seems to passively mingle with valley oaks and coast live oaks in chaparral regions. Yet, it stays close to rivers, creeks, arroyos, or low spots where water drains from winter rain. California sycamore does not follow waterways far up into forests though, as if it dislikes the deeper shade.

In urban situations, California sycamore is best for large scale landscapes, such as parks or medians of broad boulevards. It is complaisant enough for smaller landscapes, and tends to disperse roots too deeply to damage pavement. However, it grows so fast and so very big. Mature trees get to a hundred feet tall. Massive trunks are picturesquely irregular, with mottled tan and gray bark.

All the deciduous foliage generated by such large trees is generous with shade for summer, but stingy with color for autumn. Defoliation starts early and continues late, so is messy for a long time. Foliar tomentum (fuzz) is irritating to the skin, and much worse if inhaled. Anthracnose often deprives trees of their first phase of foliage in early spring. Although harmless, it makes another mess.


Flagging (sudden necrosis of distal foliage) used to indicate the beginning of a sudden end.

Phytophthora ramorum is the pathogen that initiates Sudden Oak Death Syndrome, which is known simply as SODS. Monarthrum scutellare, which are known as ambrosia beetles, and are the secondary pathogen associated with the syndrome, infest and kill tanoak and coast live oak that are infested with Phytophthora ramorum, about as quickly as symptoms are observable.

Hypoxylon thouarsianum is a tertiary but merely opportunistic pathogen associated with the syndrome. By the time it gets established within galleries excavated by the ambrosia beetles, the affected trees are almost completely necrotic. That first ‘S’ in SODS is there for a reason. It is an efficient process. Death occurs too suddenly for affected trees to drop any of their leaves!

Each of these three pathogens causes distinct symptoms. Phytophthora ramorum causes trees to bleed black tar-like fluid, and causes tanoak to exhibit foliar flagging as seen in the picture above. Monarthrum scutellare expels finely textured frass from the galleries it excavates into infected trees. Hypoxylon thouarsianum produces distinct small and black fruiting structures.

In the past several years though, Sudden Oak Death Syndrome has often been a bit less than sudden. There are a few tanoaks here that have exhibited foliar flagging for a few consecutive years, without any bleeding from the trunk or infestation by ambrosia beetle. Some coast live oaks have exhibited minor bleeding, but likewise have not become infested by ambrosia beetle.

It is as if the ambrosia beetle is no longer proliferating as it had been. It actually seems to be rather scarce. Trees that were expected to succumb suddenly to ambrosia beetle infestation are succumbing slower to infestation of only Phytophthora ramorum. The process is variable, so might have potential to kill some trees rather suddenly, but may take a few years to kill others.

Could some possibly survive?

Pollarding Is Extreme Tree Pruning

Pollarded knuckles look like science fiction.

Most arborists insist that pollarding is horticulturally incorrect. However, most of us who pollard trees in our home gardens are not arborists. Pollarding is technically detrimentally disfiguring to trees. However, some trees that are naturally short lived can live much longer if pollarded properly. That is the trick; doing it properly. Pollarding is certainly a distinctive pruning style that is not for everyone, but can be both practical and sustainable in certain situations.

Pollarding is an extreme pruning technique that involves the removal of all or almost all of the stems that grew since the last time the technique was done. The new growth gets cut back cleanly to distended ‘knuckles’ that develop at the ends of the original stems. Traditionally, one or two strategically aimed stubs from the removed new growth are left on each knuckle to form a new knuckle a bit beyond knuckles of the previous year. Locally though, stubs are typically omitted.

New growth must get cut back cleanly so that the wounds can get compartmentalized (healed over) as efficiently as possibly. Stubs interfere with this process. If one or two stubs are left on knuckles to form new knuckles, they should be long enough to get some distance from the original stubs, but short enough to not be too awkward. Knuckles should not get cut off! Such large wounds do not compartmentalize fast enough to avoid rotting.

Pollarding can only be done in winter, both because plants are dormant, and also because the weather is not so dangerous. New growth starts to shade exposed bark before it gets scalded by intensifying sunlight and heat in summer. Once they come out of dormancy, plants would be seriously distressed by such severe pruning. Because new growth is so vigorous after pollarding, it can become sloppy if pollarded less than annually. Some plants that grow slowly or produce stout stems may get pollarded less frequently.

London plane (sycamore) and fruitless mulberry are the most commonly pollarded trees. Silver maple, silk tree and various elms, willows and poplars adapt well to pollarding as well. Locust and purple leaf plum can be pollarded, but will be deprived of bloom. Bottlebrush can bloom later in the same year after getting pollarded, and probably will not need annual pollarding anyway. Pollarded bay trees can be kept small, and will provide better herbal foliage. Certain eucalyptus can be kept juvenile if their juvenile foliage is more appealing than their adult foliage.

Horridculture – Memorials

Where are the cedars?

Memorial trees should be remembered . . . right? I mean, they are planted to remind us of . . . something, or . . . someone. They are typically trees that will be around for a long time, because that is how important memories should be. Redwoods and oaks work nicely. Most get outfitted with plaques to remind everyone what the trees are there to remind us of.

The old original Sunnyvale City Hall was landscaped with several memorial trees. The most prominent were redwoods and cedars that were mostly planted as memorials for local veterans of various wars. They accumulated over several decades and a few wars. City Hall seemed like a good place for them, where they could live for a long time without bother.

However, City Hall was demolished in the late 1970s, and replaced with a big mall. The larger redwood and cedar memorial trees were salvaged as the mall was build around them. Most survived in a courtyard within the mall until the mall was partly demolished less than a quarter of a century later.

All the cedar memorial trees died in captivity within the courtyard. One redwood that was not a memorial was added to the group where one of the cedars had been.

Prior to the demolition of the courtyard, I needed to inspect the surviving redwood to prescribe procedures for safe removal of surface pavement, and subsequent protection of exposed roots. The surviving trees were in remarkably good health. I was not very worried about them. What bothered me though, was the complete disregard for their historical significance.

The plaques associated with these memorial trees were a mess. It was as if they all had been collected from their respective trees, mixed up, and replaced randomly. Plaques from the absent cedars were assigned to some of the surviving redwoods. The oldest and grandest memorial redwood was labeled as the redwood that was added last, after the mall was built, and therefore of no historical significance. The smallest and youngest redwood that really was added after the mall was built was labeled as one of the more historically significant memorial trees.

I believe that all the trees that were there during my inspection are still quite healthy within a small park space that was built around them. I have no idea if they are outfitted with plaques. If they are, I can not help but doubt the accuracy of those plaques.