Mysterious 'ghost redwoods' may survive to help nearby trees

Albino redwood
CC BY 2.0 Cole Shatto/Redwood Coast

Albino redwoods shouldn’t exist, but they do. Now a biologist finds a possible explanation in the tree network that thrives beneath the forest floor.

Rare in their improbable shimmering white, albino redwoods defy the popular logic of trees. With a mere 406 of the apparitions flittering throughout California’s coastal forests, the bone-white trees lack chlorophyll, the green pigment that allows plants to make food from light by the magic of photosynthesis. As Sarah Kaplan notes in the Washington Post, they are incapable of the one thing that all trees must do to live.

Albino redwoods should not exist, but they do, and how they do that has baffled researchers for more than a century. But now biologist Zane Moore from the University of California in Davis may have discovered an answer to the mystery of these exquisite trees.

Albino redwoodKevin Bertolero/flickr/CC BY 2.0

Redwoods are famously complicated. Coast redwoods (Sequoia sempervirens) rank among the tallest organisms on Earth and boast longevity of some 2,500 years. As Kaplan reports, the trees' genomes have 32 billion base pairs compared to our own 3.2 billion, and they carry six copies of each chromosome instead of two. “No one has successfully sequenced the redwood genome,” she writes, “making it impossible to pinpoint the mutation that causes their albinism.”

Plus, they can clones themselves, resulting in a rambling, complex network of roots beneath the forest floor with which trees communicate. During lean seasons, the trees use this network to share nutrients. Researchers have seen this firsthand by introducing dye to trees on one side of a grove and tracing it all the way to the farther reaches.

Albino redwoodRedwood Coast/flickr/CC BY 2.0

But as soon as summer comes, the trees become a bit more solitary in their survival efforts and begin fending for themselves. Those who can’t cut the mustard are cut off from the shared system and cast aside in the autumn “needle drop.” So if albino redwoods can’t photosynthesize, why are they allowed to stick around?

Moore is an expert on the albino redwoods of the Santa Cruz mountains and says that albino redwoods take advantage of their communal root system by sipping on sugars produced by their most robust neighbors. “A lot of people thought they were parasites,” he says. “They even called them 'vampire trees.' "

This didn’t jibe with Moore; redwoods are too efficient to put up with parasites. “Redwood trees are smarter than that,” he says.

After conducting research on the trees, Moore and his colleagues found that the unusual trees liked to grow where the conditions are less healthy, suggesting the potential that environmental pressure might allow the mutants to thrive.

Albino redwoodCole Shatto/CC BY 2.0

Upon analyzing albino needles from trees up and down the coast, they found that the white leaves were soaked with what Kaplan calls “a deadly cocktail of cadmium, copper and nickel.” She writes:

On average, white needles contained twice as many parts per million of these noxious heavy metals as their green counterparts; some had enough metals to kill them ten times over. Moore thinks faulty stomata — the pores through which plants exhale water — are responsible: plants that lose liquid faster must also drink more, meaning that the albino trees have twice as much metal-laden water running through their systems.

“It seems like the albino trees are just sucking these heavy metals up out of the soil,” Moore says. “They're basically poisoning themselves.”

Based on this startling discovery, Moore theorizes that the wan trees are not parasites, but rather in a symbiotic relationship with their healthy neighbors, acting as a “reservoir for poison in exchange for the sugar they need to survive.”

As we find out more and more about how trees take care of each other – that they form bonds and look out for each other, and can even recognize their offspring – this comes as little surprise to some of us.

Moore says that he needs to study the theory further, bit if this is indeed the case, albino trees could be put to work in polluted areas to help save other trees. The phantom trees planted strategically to take one for the team, but in doing so, given what they need to live.

Albino redwoodAlex Nelson/flickr/CC BY 2.0

But regardless, the ghosts clearly have their place in the forest.

“When you're looking at redwoods, you need to take into account more than just one tree,” he says. “It's the interactions of the community as a whole that makes the forest. That interconnection from root to root to root.”

Via The Washington Post.

Tags: California | Trees

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