Coastal redwood, Sequoia sempervirens, are remarkable stable trees. They rarely fall, which is how they get to be thousands of years old. They prefer to live in groups, where they mesh their roots together, and shelter each other from wind. Those that live outside of a group stay shorter than forest trees, and typically develop multiple trunks that function as a group.
However, they are also remarkably weak in regard to their structural integrity. Limbs are easily broken away from their vertical trunks by wind. Snow, which is rare within their natural range, causes significantly more damage than wind, which is probably why their natural range does not extend into snowy climates. Trees with co-dominant leaders (double trunks that divide from single trunks above grade) have potential to split at the union of the double trunks. Such unions are typically at such acute angles, that the trunks press against each other rather than fuse together through impenetrable compressed bark.
Leaning redwoods such as these that were shown earlier this morning, are potentially hazardous, not because they are likely to fall over, but because they might be likely to break. The trunks are designed to support weight vertically. The asymmetrical distribution of weight supported by these two trunks exerts inordinate lateral tension on the trunks. To make matters worse, the trunk to the left is divided into two co-dominant leaders, although the union does not appear to be at a typically acute angle. (The lower trunk is now behaving more as a big limb than as a secondary trunk.)
I would guess that these two trees are genetically identical trunks from the same root system. Such seemingly pliable trunk structure is uncommon, and it is very unlikely that two such similar trees would just coincidentally appear within such minimal proximity to each other. Redwoods often develop multiple trunks from the same root system, particularly as they regenerate after harvest.
The good news is that these two trunks have survived like this long enough to develop ‘reaction’ wood, which is just like it sounds; a bit of extra wood to compensate for compression on the inside of the bend. Also, they are sheltered from wind by the other redwood in the forest around them.
If there were lawns and fences in this neighborhood, the grass would likely seem to be greener on the other side of the fence. In this situation, the greenhouse probably seemed to be more comfortable than being left out in the storm. This tall Douglas fir tree dropped in to find out. It did not go well. What remains can be seen in the middle of the picture above, just to the right of the fallen fir, and in the close up of the picture below.
Miraculously, the two coastal redwood trees that caught and guided the fir to a direct hit on the greenhouse also prevented it from destroying the associated house. Well, at least the redwood on the left did. There would have been less damage if the fir had fallen farther to the right. Regardless, a deck was crushed, an eave was destroyed, but the rear wall of the home was barely nudged. Not even the windows there were broken!
Falling debris punched a few holes in the roof, but without structural damage. The patio of the big building to the right was littered with debris that was easily removed. After limbs are removed from the damaged house, much of the carcass of the fallen fir will remain on the forest floor. It decays efficiently here.
Incidentally, this fir was about to be removed. It had been identified as too risky for the neighborhood. Although they are not visible in the pictures, there are a few other homes in the neighborhood. The cabin that I stayed in for more than a week is just beyond where the top of the fir landed. The stovepipe that is visible in the background of the second of my ‘Six on Saturday – Cabin Fever’ pictures from January 5 is the same stove pipe that is visible on the roof of the home that was nearly destroyed by the fallen fir. https://tonytomeo.com/2019/01/05/six-on-saturday-cabin-fever/
(The stove pipe circled by the yellow oval just above the center of the picture above is the same stove pipe circled by the yellow oval just right of the middle of the upper margin of the picture below.)
Fire has always been a part of life in most of California. That is why almost all native flora benefits from it, and has developed an efficient system and schedule for not only living with it, but exploiting it.
Within a few years after a fire, the pioneer species are the first to regenerate. They are aggressive, but short lived. Some are annuals. Others are trees that grow fast and then die out as the slower growing but longer lived trees dominate. Some of the longer lived trees might have been there all along, since they have developed ways of surviving fire.
Big valley oaks and coast live oaks that live out in the open away from other forest trees can survive for centuries because the grasses around them burn off fast and relatively harmlessly. Giant redwoods and some pines survive by standing high above the more combustible fuel below. Coastal redwood survives for centuries by being less combustible than other species. Desert fan palms protect their single terminal buds inside their massive non combustible trunks, while their beards of old dead foliage burns hot enough to incinerate competing species. There are too many ingenious ways that plants survive fire and even use it to their advantage to write about; but the point is that they know what they are doing, and they know how to live with fire.
This system of ecology has been disrupted, but not just by people cutting down too many trees and starting too many fires. The problem now is that not enough trees are getting cut down, and fires are unable to burn that which relies on burning.
In this region, pioneer species and an unnatural mix of forest trees moved in where the redwoods were harvested. This makes what had been less combustible redwood forest more combustible than it naturally is. It will take centuries for the redwoods to reclaim their territory and crowd out more of the hardwood trees. Also, because the redwoods regenerate with many trunks from each individual trunk that was harvested, even the redwoods are more crowded and combustible than they would naturally be. While they are still relatively young, their foliar canopies are low and intermingled with the other more combustible trees. It is certainly not possible to cut down enough trees to repair the damage, but protecting too many of the wrong trees and outlawing selective harvest of second growth redwood only promotes combustibility of the local forests.
Other forests, whether formerly harvested or not, experience similar problems. Because they are not burning as frequently as they used to, they are not being regularly purged and restored, but are instead becoming more crowded and combustible than they would naturally be. Diseases and pathogens are proliferating in the geriatric vegetation, and vegetation that succumbs provide more fuel, which also enhances combustibility.
Although there are many (MANY) more fires that are started by human activity now than there ever was naturally, such fires can not burn the vast areas that naturally occurring fires had naturally burned. There are just too many of us living and working here. Forests that are deprived of fire continue to proliferate more combustible biomass. Again, there is no remedy to this. Fires must be controlled and confined as much as possible.
Paradise is gone now. It burned on Thursday. Our region more than two hundred miles to the south is gray with abundant smoke from the Camp Fire that continues to burn there. Two other major fires burn in Ventura and Los Angeles Counties, more than three hundred miles to the south of here. Paradise Park just to the south of here was protected from the much smaller Rincon Fire that filled the Valley with harsh smoke for days after it was contained. Sadly, for this region, this is all part of nature.
I do not remember on what days these pictures were taken. The first picture at the top was taken toward the sunrise, just prior to sunrise. The second picture above was taken later after noon, probably on the same day. The two pictures below were taken in the evening, perhaps on the day after.