Sonoma Marin Area Rail Transit announced Thursday that it's delaying its planned removal of a super-rare chimera albino coast redwood in Cotati, pending additional expert analysis of the tree and study of alternatives to destroying it.
The tree is located within the railroad right-of-way at East Cotati Avenue. The redwood in question is extraordinarily unusual on two accounts: it's both albino and a chimera. The albino part of that description means, among other things, that its needles lack chlorophyll to give them their typical green appearance.
In a story the other day, the Santa Rosa Press Democrat did a nice job explaining what the "chimera" part of the tree's physical makeup means:
The tree is a scientific treasure, said Zane Moore, a botany student at Colorado State University and a widely known researcher in chlorophyll-deficient, or albino, redwoods. ... Cotati's tree isn't just an albino, but a chimera — a phenomenon seen in only a handful of naturally occurring redwoods in the world.
“A chimera means the plant has two genotypes, two sets of DNA growing in one plant,” Moore explained. “This tree is one of very few known chimeric redwoods in the world, and there is only one chimeric redwood known to exhibit the same style of albinism.”
The other is a 5-foot-tall immature bush with fewer than five albino shoots, which is of limited scientific use at this point, he said.
In Cotati's mature tree, green and white needles appear on the same limb, similar to a candy cane's alternating red and white stripes, Stapleton said.
To the untrained eye, the needles near its top appear oddly yellow, as if it may be unhealthy. Upon closer inspection, the limbs show one of the rarest genetic abnormalities in science: the dual-DNA variegation of green and white needles on the same stem.
It is the world's largest and tallest chimera, at 52 feet.
Louise Santero has lived in Cotati for 70 years, and the redwood tree sits just down the street from her home. She says needles change color throughout the year: "They're deeper green during the spring, and then when winter time comes, that's when it changes."
Santero estimates that the tree is 67 or 68 years old. Her former neighbor, Pete Tapian, planted the tree, but its exact provenance is unknown. "Where he got it, we have no idea," she said. "His family doesn't know either. The girls would say that at nighttime, their dad would go out and cover the tree so it would be protected."
Santero and other residents say removing the tree is unnecessary, but up until Thursday SMART officials said they had to comply with federal safety requirements.
One set of rail tracks currently runs past the tree, but a second track will soon be added, putting the tree in a dangerous place. Earlier this week, a SMART spokesperson said the transit agency had tried to shift the alignment of its new tracks as far east as possible, but that still wouldn't leave enough clearance for the tree to stay.
SMART also looked at pruning the tree back, but that would have meant removing all of the branches on one side of the tree, and it still would have been within falling distance of the tracks, making it a safety hazard.
SMART officials have suggested taking more than 1,000 cuttings from the tree and giving them to a private nursery to be propagated. Arborist Tom Stapleton, who strongly opposes cutting down the tree or moving it, says SMART's propagation plan is flawed.
"Because you have both genotypes living on the same plant material, if you don't find the right particular branch that has the particular kind of chimerism, it will not be stable," Stapleton said. Over time, he predicts that the normal green genotype would overpower the albinism, and the resulting tree would look like a normal redwood.
Thursday's announcement from SMART's General Manager Farhad Mansourian sounds like a delay more than a reprieve:
“SMART is a local project. We are building something that will be part of the community. There is no question that we have to comply with safety requirements, and within that we have and will continue to take extreme care with the environmental elements of the project. Therefore, although we have been very proactive in doing due diligence, I have halted the process to take the time to bring in additional independent experts to examine and verify the analysis that was performed in September 2012 , as part of our environmental permitting, for this specific tree.”