P81208KKThe tufts of small branches that so often develop where limbs were pruned from the trunks of a coast live oaks are sometimes referred to as ‘tumbleweeds’. They are about the same size as an average tumbleweed. By the time the get any larger, most of the smaller stems have subordinated and died out, leaving only a few more defined dominant stems, which will continue the process until even fewer or a single new branch dominates. Such tumbleweeds, as well as stems that originated from such growth, are weakly attached to the main trunks. They often get pruned off for the same reason that the limbs that were there before got pruned off, or because they are expected to be weakly attached. If they remain long enough, they can of course develop into new limbs.

Tufts of the same sort of growth on sycamores or other deciduous trees are known more simply as . . . ‘tufts’ I bet you didn’t see that coming. They can get much bigger than tumbleweeds before they develop much distinction between the dominant and subordinate growth. Because tuft growth is innately vigorous, the leaves are bigger and coarser. Then, when the rest of the deciduous trees that produce them defoliate in autumn, the tufts retain their green foliage until it gets ruined by frost.

This big sycamore dropped its top over summer. https://tonytomeo.com/2018/07/14/nature-is-messy/ The tufts developed on the big trunks that became exposed to sunlight by the loss of the upper canopy above. The tree will naturally try to replace its top, but will also naturally be even more disfigured and structurally deficient than it already was. As the tufts develop into limbs, and the limbs get heavy with foliage, they will be very likely to break away and fall. As unpleasant as all that sounds, it is quite natural for such a mature sycamore who is so old that he just doesn’t care who gets offended anymore.

Big Trees Are Bad Houseplants

P81111By ‘big trees’, I don’t mean the various ficus trees that can grow up to the ceiling, and be quite happy inside. I am referring to the shade trees that live out in the yard, or forest trees that live beyond that. They are outside for a reason . . . or actually, several reasons. They are too big to bring inside. They probably would not like the climate inside. No one wants to rake fallen autumn leaves inside. Well, you get the point.
Unfortunately, on rare occasion, big trees that are outside end up partly inside by falling or dropping limbs onto the homes that they provide shade for. Just like trees seem to fall onto certain types of cars more than others ( tonytomeo.com/2018/11/04/trees-hate-cars ), trees seem to fall onto certain types of homes more than others. The difference between the homes that trees seem to dislike and the cars that they seem to dislike, is that there are actually reasons why some types of architecture is more susceptible to falling limbs or trees.
First of all, just as some trees seem to avoid falling on cars, some seem to avoid falling on houses.
Coastal redwoods in landscape situations are remarkably stable. In my entire career, I have inspected only three that have fallen. One had a massive pair of trunks that split apart and fell away from each other. Although they were on the fence line between two closely set urban homes, and there was almost no place for them to fall without destroying one home or another, they did the seemingly impossible. They literally fell onto the property line. One trunk fell out into the street. The other fell back into the backyards of the homes behind. The fence was pressed into the ground. The landscapes were seriously damaged. Gutters were stripped from both adjacent homes. Otherwise, there was NO structural damage to any of the homes. I am still amazed at how minimal the damage was!
The massive coast live oak two doors down from my former home in town was just as talented. It sprawled out over its associated home and the front yards of the two adjacent homes. It was so broad that I would not have believed that it could have fallen down without destroying one of the homes. Yet, it did exactly that . . . as I watched from my dining room. During a windy storm, it fell right toward me, and landed squarely in the front yard next door. It broke a few rafters on the edges of the eaves, and tore the gutters off, but that was the worst of the damage. It somehow found the best spot to fall where it would cause the least amount of damage.
Not all homes are so fortunate.
Victorian homes though, do not seem to be targeted by trees as much as others are. Most are closer to downtown, away from tall or very broad forest trees. Many are on somewhat narrow parcels that can not accommodate disproportionately large trees like the coast live oak in the picture above. Broadly sprawling trees tend to be too low to extend their limbs over the roofs of taller two story Victorian homes. Although taller than most other types of homes, two story Victorian homes do not occupy as much area as other homes, so are not such big targets.
Low profile homes of ranch architecture, or similar types of architecture, are more likely to be damaged by falling limbs or trees. Many happen to be located in suburban or rural areas, closer to bigger and broader forest trees. Their wider parcels can accommodate larger trees. Their roofs are low enough for trees to extend limbs over. Because they tend to be on a single level, they occupy more area, so are larger targets.

Trees Hate Cars

P71028That is a myth. They do not hate all cars. They just hate particular cars.
I did an internship with arborists in the summer of 1988, and have never been able to get away from arboriculture. Even as a nurseryman, I still sometimes work for arborists, and inspect trees that they are concerned with. I have seen many of their subject trees that have fallen onto parked cars, homes and whatever trees fall onto. I have noticed particular patterns.
Trees are more careful with Buick, Oldsmobile, Pontiac, Chrysler, Volkswagen, Mercedes Benz, and Datsun or Nissan. I have seen them put considerable effort into avoiding these cars when dropping limbs or falling over. When I was in school in San Luis Obispo, I drove my neighbor’s 1969 Oldsmobile Cutlass out from under his Chinese elm that fell over it. The tree held itself up on limbs that landed on the opposite side of the driveway so that the car came out from under it completely unharmed. When I lived in town in Los Gatos, a massive coast live oak two doors down fell harmlessly into the front yard next door. The roots pulled up in front of and behind a Volkswagen GTI that was parked at the curb, and barely tossed an ounce or two of mud onto the hood. A few big olive trees did the same at a large condominium complex in San Jose during a windy storm, leaving nothing more than a bunch of leaves and olives on top of a classic Mercedes Benz sedan and an old Datsun B210. These are certainly not the only examples. This seems to be a common theme for these particular cars.
I can not say the same for Mercury, Plymouth, Jeep, Cadillac, Mazda, Toyota, Lexus, Honda, Subaru, Infinity or Volvo. I have never seen trees damage or avoid damaging them.
Damage to Ford, Dodge, Audi, Isuzu and BMW did not see to be targeted. It was the sort of random damage that one would expect from a tree innocently falling onto parked cars.
Both of the only two cars that I know of that were squashed while being driven were Lincoln Navigators. That is not a good statistic at all. One was hit by a falling Canary Island pine in Fremont. The other was clobbered by a Coast live oak in Saratoga. No one was hurt; but the cars were killed.
I have seen only one Chevrolet damaged by a tree, but it was vicious! It was one of only three coastal redwood trees in a landscape situation that I had ever seen fall, although ‘fall’ does not adequately describe what this tree did. Without enough wind to damage adjacent and notoriously structurally deficient California pepper and Chinese elm trees, this redwood seemed to jump out of the ground to land on top of an Astro Van about twenty feet away! I do not think the tree was targeting it because it was a Chevrolet. The tree obviously hated this specific Astro Van VERY much.
Acura seems to be the second most hated sort of car among trees. They are less common than Honda, but I have never seen a Honda damaged by a tree that it did not run into first. Yet, I have seen at least three Acuras destroyed by a coast live oak, a blue gum eucalyptus and a Monterey pine. That is an inordinate number!
The car that trees seem to hate most is Porsche! They are uncommon cars, and are probably less common than any other car that I have ever seen damaged or destroyed by trees. Yet, I have probably seen more of them destroyed than Acuras, including one that was attacked as blatantly as the Astro Van was attacked by the small redwood. The ONLY blue spruce that I have ever seen fall landed squarely down the middle of a new Cayenne, back when they were the first SUV that Porsche made. The densely foliated canopy enveloped the car so thoroughly that only the middle of the tailgate was visible.
It would be interesting to know if insurance companies have determined if any particular types of cars are more likely to be damaged or destroyed by trees than any other. I would think that if the trends that I have noticed are accurate, that insurance companies would be aware of them as well. I am also curious to know if other arborists have noticed similar trends.P80106

More Spontaneous Limb Failure

P80707KP80707K+(This was copied and modified from the Facebook page of Felton League.)

Warm and humid weather is an uncomfortable change for an otherwise mild summer. It also causes spontaneous limb failure among trees, particular those in riparian areas or irrigated landscapes. What sounded like muffled firecrackers was the (slow but steady) fracturing of another cottonwood limb in Felton Covered Bridge Park. (Another incident of spontaneous limb failure was mentioned a few days ago.) (https://tonytomeo.wordpress.com/2018/07/01/spontaneous-limb-failure/) This one was over the picnic area adjacent to the playground. The fallen portion of the limb was less than a foot in diameter, although it was slighter wider than a foot wide where the fracture originated. It fell onto the middle of a group of picnic tables, with the fractured proximal end remaining suspended and attached to the originating tree. Because it remained attached and fractured slowly, the limb did not fall with enough inertia to damage the picnic tables. It was removed very efficiently.P80707K++(continued)

Cottonwood, sweetgum, coast live oak, valley oak, Chinese elm, California bay, California sycamore, willow and various eucalypti are particularly susceptible to spontaneous limb failure. The oaks and eucalypti are particularly dangerous. Oak limbs are extremely heavy, and tend to break away cleanly and suddenly rather than fall slowly while still attached. Eucalypti limbs likewise break away cleanly, and then fall from great heights without many lower limbs to slow them down. As they start to fracture, Chinese elm and willow limbs might stay attached to the main trunks or the larger limbs from which they originate, which might slow them down somewhat.

Sadly, spontaneous limb failure does more than damage whatever the falling limbs land on. It can also disfigure the affected trees so severely that they must be removed rather than salvaged.P80707K+++


P80523This unhappy native white alder, Alnus rhombifolia, had been deteriorating for quite a while. White alders do not last long even in the wild. A few nearby have already been removed. This one is next. They were nice and shady when the landscape was new. Nicely maturing sycamores and a bigleaf maple can take over for this one now.

As bad as it looks, this nasty stain had nothing to do with the imminent doom of this tree. It developed only recently, and very quickly. It is not nearly as bad as it looks. If the tree were not to be removed, it could survive with this problem for quite a while. Other healthier trees can live with it for many years or indefinitely, and some actually recover.

It is ‘flux’. More specifically, it is slime flux, which is also known as bacterial wetwood. The obvious symptoms are this unsightly bleeding and staining. A less obvious symptom is the swelling that caused the fissure in the bark from which the unsightly fluid is draining. The fluid can smell nasty!

Furrows in the bark develop naturally as the trunk expands over many years. They do not penetrate through the bark into the cambium below.

Fissures are fractures that penetrate through the bark and into the cambium. The fissure in these pictures developed so recently that the orange interior of the bark has not oxidized to tan or gray yet. The fissure is about six inches long, and slightly lower than a doorknob.

Even for healthy trees, there is no remedy for slime flux infection. It can only be left to do whatever is going to do. It can accelerate internal decay, but is otherwise not as detrimental to the health of an infected tree as it would seem to be.P80523+P80523++

(The article from my weekly gardening column that is typically posted on Thursday was posted yesterday, which is why this article, which is more appropriate for Wednesday is posted today.)

Big Trees Really Need Arborists

41203thumbStormy winter weather always reminds some of us that our trees need some attention. Wind can break limbs. If the weather gets really nasty, trees can be destabilized by strong wind, particularly if the soil is moistened by rain. However, the truth is that arboriculture, which is the horticulture of trees, is important throughout the year. We just become more aware of it when weather threatens.

Not only is arboriculture important throughout the year, but it is also the most important aspect of horticulture in most gardens that are outfitted with trees. After all, trees are the most significant features of such landscapes. Their shade affects the homes and garden spaces around them. If they drop limbs or fall, they can cause significant damage. Many get far too big for us to maintain.

This is why we need arborists, the horticulturists who specialize in trees. Arborists can evaluate the health, stability and structural integrity of trees, and prescribe any necessary arboricultural procedures. In order to issue a permit to remove a tree, most municipalities require an inspection and report from an arborist who is certified by the International Society of Arboriculture, or ISA.

ISA Certified Arborists have passed an examination of their arboricultural expertise, and maintain their certification by continued involvement with ISA educational seminars, workshops and classes. The ISA is the standardizing resource for the promotion of the most important arboricultural technology, and maintains discriminating standards. ISA certification is quite a commitment.

www.isa-arbor.com, the website of the ISA, is an excellent resource for anyone in need of the services of a certified arborist. The registry of arborists can identify and find an arborist directly by name, or regionally by city or ZIP code. The site is also useful for information about proper arboriculture and trees, for those of us who maintain our own small trees, or want to select new trees.

Trusting the wrong professional to maintain trees can be very risky. Even gardeners who are proficient at mowing lawns and shearing hedges may not be adequately knowledgeable about proper arboriculture. Instead of correcting problems, improper pruning can disfigure trees and limbs, and actually compromise their structural integrity. Sadly, it is not uncommon for otherwise healthy, stable and well structured trees to be ruined by those hired to care for them.