Story of a tree that killed
By Thomas Yeatts
Some three hundred years ago, the giant coast live oaks that now dot the West Marin landscape, including the one that fell and killed a Lagunitas resident in late December, were saplings. Of the ones that weathered the years of winter rain and wind, and survived exposure to pests and disease, some grew to become centerpieces in the yards of the first homes built in the San Geronimo Valley in the early twentieth century. Many of these trees still stand today, providing shade and beauty, but in some cases becoming nuisances and threats to the safety of those who live under their expansive canopies.
The live oak that fell and killed Jasmine Clower, a local organic farmer, was estimated to be 300 years old and 100 ft. tall at the time it was uprooted by a storm gust and fell on the small cottage where she was living. Some say there were indications that the tree was unstable, raising the issue of what notice the property owners had of the tree's danger. Because large trees like this one pose a widespread, if silent, threat to the community, and because these trees are vital to West Marin's rural character, the Light sought to investigate what was known about the tree prior to the accident, and what the duties of homeowners and tree caretakers are, generally, as regards tree maintenance.
On Dec. 27, the morning after Clower was killed, the orange and yellow geometry of cranes and construction crews were seen in clusters in Lagunitas and in other parts of West Marin removing giant trunks and large, looming canopies.
Workers spent approximately eight days, working 10-hour shifts, removing the live oak which crushed part of a house on Barranca Rd. and demolished the small cottage out back where Clower lived, according to the neighbors.
In the days following, tree maintenance crews were busy removing and pruning Monterey pines and cypresses on at least two other sites in Bolinas. Residents cited safety, practicality, peace of mind and money as reasons why they were undertaking the maintenance.
The morning after the storm
At noon on the day after the live oak fell in Lagunitas, David Jenkins, a Light employee who lives near the house that was damaged, was called on site to take notes and pictures.
Jenkins was informed by neighbors, firemen and other authorities that Craig Swift was the tree expert on site. After confirming the first name of the victim, Jenkins was permitted on to a property across the creek from the damaged lot by one of the neighbor's friends, where he took several photos of the scene. He then left the property to speak with other onlookers.
Jenkins visited the home of Loys Hansen, a resident of 35 years who lives two houses down from the damaged property. Speaking with her outside her residence, she informed him that approximately 15 years ago a large branch had fallen from the tree. At the time, the tree was cabled for support, she said.
Speaking with the arborist
After witnessing the removal of Clower's body from out front of Hansen's house, Jenkins revisited the property from where he had taken photos of the damage earlier. The neighbor's friend mentioned above accompanied him also the second time he visited the property.
Jenkins was taking photos again from the vantage across the creek when Craig Swift, an arborist, saw the two nearby and spoke. "I know this tree. I've trimmed it twice, thinned it and lightened it. It was unbalanced," said Swift, speaking openly with Jenkins.
"The tree doesn't have any sign of disease, but saturation has made it difficult for good roots to grow," he said. "Last time I did an arborist report I told them it was time to take it down."
Swift would not state the date of his last inspection of the site, or comment if he was referring to the current owners of the property or to previous owners.
Sierra Salin, the current owner of the property on Barranca Rd. on which the small cottage which Clower rented stood, said there was no official arborist report on the condition of the oak stating that it should have been removed. The tree was inspected by professionals numerous times since she bought the property three and one-half years ago, she said.
"Several professionals had a look at the tree when we bought the property and none of them expressed an urgent need to bring it down," Salin said.
After a story ran in the Dec. 28 issue of the Light, Swift's wife contacted the editor and said that she checked company records and could not find a formal arborist report on the tree, but would not state whether Swift told Salin the tree was unsafe in a less formal manner.
Swift is listed in advertisements as a certified arborist, but not as a consulting arborist. The distinction is important because you will often have competing or conflicting arborist reports in cases where liability is disputed, said Barri Bonapart, an attorney based in Marin specializing in tree law.
Clower's neighbors say they never heard Salin or Clower comment about the health of the tree, or themselves perceive any vulnerability in its structure so severe that it required immediate attention.
According to Swift, as well as neighbors, there was no outward sign of disease affecting the trunk. Sudden Oak Death, a common water mould infection in oaks, would manifest a visible red stain on the trunk within feet of the ground, according to Laura Alber of Urban Forest Consulting, a registered consulting arborist who holds a master's degree in forestry from Berkeley.
"It was an absolutely gorgeous tree," said Hansen. The tree, which had shaded her porch from direct light at sunset, loomed large even as it stood two houses down. "It was really old, but it looked healthy," she said.
What experts say
The health of a tree cannot always be ascertained simply by looking at it, said Bonapart. "Usually when a tree falls in an urban [populated] environment, had somebody been paying closer attention it could have been predicted and prevented," she said.
John Sevier, a certified arborist and tree accident expert based in San Diego, believes that by paying close attention to events like an earlier limb break, catastrophic events resulting from whole failure can be prevented more often.
"Some trees are predisposed to limb break. Some have a history of breaking limbs over and over," said Sevier. "If you have a tree that is leaning and its strength is being undermined by a rushing of water, two things can be done: the force that is undermining the tree [running water] can be minimized or abated, or the force that is weighing down the tree [the canopy] can be minimized," he said.
An early sign
A big limb, about two and one-half ft. in diameter, fell off the coast live oak that killed Clower about 15 to 20 years ago, said Hansen, speaking to this reporter a week after the accident. Hansen, unlike Salin, had seen the tree grow over three decades. The limb that fell crushed a section of fence that separates her yard from her neighbor's. At the time the limb broke the tree had a cable system linking the branches for mutual support, she said. Those cables popped off when the branch fell, and Hansen does not know if those cables were ever replaced.
Neither the property's former owners nor the arborists who had visited the site in recent years could be reached to comment on whether or not the live oak was being supported by a cable system at the time the tree fell, or whether it had been regularly pruned.
One neighbor, who wished to remain anonymous, said she saw some rotting at the core of the dismembered trunk when she visited the site after the live oak had been chopped down for removal.
Some degree of rotting, however, is normal in older trees, said Alber, noting that 300 years reflects the upper limit of the life span of a coast live oak.
"A live oak may take 100 years to grow to maturity, 100 years to live, and 100 years to die," she said. "They may take decades to die, or they can die suddenly in a storm."
The majority of trees fall during the winter in Marin because of the saturation of the soil or because the creeks run fast cutting away banks and destabilizing the soil around them, according to Jim MacDonald, a park ranger stationed at Muir Woods.
The fact that the tree fell from the base would suggest that it was a root failure rather than a trunk failure, Alber said. The proximity of the tree to the creek, in combination with high wind events called "micro-bursts," whose number climaxes between November and January, may have contributed to the tree's collapse, she said.
Reprinted with permission from Pt. Reyes Light. © 2007. Tomales Bay Publishing company.