Ghost-Busters: On the trail of the albino redwood
It’s a pale ghost-like tree in the coastal redwood forests. It’s a mutant and very rare. It’s a white-needled tree that would make any gathering of coniferites gasp with excitement. It is also a mystery, although one that is slowly becoming unraveled.
The albino coast redwood (Sequoia sempervirens) has been observed for 150 years but, as was noted after a branch was displayed at the California Academy of Sciences meeting in 1866, “no explanation or theory was offered to account for this curious, abnormal blanching of the foliage...”
More than 30 years later, in 1898, Stanford plant physiologist George James Peirce studied albino sprouts growing in the Santa Cruz Mountains and determined that the needle anatomy and chemistry were somewhat different from nearby green specimens. He also showed that the albino sprouts could not be propagated — or survive — on their own.
Nothing more happened until 1976, when forester Dale Holderman happened upon an albino redwood in the Santa Cruz Mountains that had male albino cones. This discovery was a major milestone in understanding redwood morphology, and led to the exciting possibility that these mutants could be propagated. Indeed, in 1977 Holderman succeeded in crosspollinating an albino redwood to a normal green redwood, producing the first chimeric hybrids.
Then, a break-through
In 1997 arborist Tom Stapleton discovered and successfully propagated the first wild albino chimeric redwood known. He told us via email, “I approached Mr. Holderman in the summer of 2012 with a collaborative idea to attempt a propagation experiment off his chimera-albinos originating in the 1977 cross.
He explained that prior attempts to asexually propagate these cuttings were met with failure. With permission, I carefully selected cuttings that exhibited specific periclinal chimeric traits. After procuring 10 cuttings I was able to successfully root eight of them in a special media mix. After observing stable albino and green characteristics, Mr. Holderman and I filed for a patent in June, 2014.” The variegated, patented coast redwood with distinctive white and green needles has been named ‘Mosaic Delight.’
“Sadly, Dale Holderman passed away just two days after the patent was approved on April 5, 2016. I am forever grateful for the opportunity Dale gave me to continue his pioneering research.”
He added that the tree that produced the albino pollen in 1976 has never done it again.
However, in the spring of 2013, a redwood displaying a rather large teardrop aerial albino was found exhibiting albino male cones. More astounding, the mutation also displayed fully developed female albino cones. In the fall of 2013 seeds from these albino cones were planted in a research greenhouse. Seedlings emerged, but not all were white. This led to speculation that not all the pollen which fertilized the albino female cones had originated from within the mutation. Unlike Holderman’s hybrid seedlings 36 years earlier, these were either pure green or pure white, with no variegation. Lacking the ability to photosynthesize, the white seedlings died in five weeks. The green ones continued to grow, and have not displayed any signs of albinism.
Stapleton planted 2,673 seeds from the teardrop albino. Only 119 germinated. Of these 92 were albino and 27 were green.
In percentages, 4.45% of the seeds planted seeds germinated, 3.44% were albino and 1.01% were green. In other words, viability was very low and genotype preference was approximately 30% green to 70% albino.
While the mystery of the ghostly white redwoods remains, it’s being probed by a plant biology PhD student at U.C. Davis, Zane Moore. Moore, working with Stapleton and others, set out to locate every known albino redwood. They found only 432 in the entire world. (A few years ago that number was 200: more are being discovered regularly.) He then analyzed clippings from these trees, and from their green neighbors. He found that the white needles were loaded with what should have been a fatal dose of cadmium, copper and nickel — twice as many parts per million as their green neighbors. Yet, they appear to thrive.
Looking forward, Stapleton and Moore have embarked on an experiment which hopefully will shed light on these fascinating questions regarding metal toxicity in coast redwoods. In his greenhouse, Stapleton is working with Moore to test a group of chimeric albino redwoods with doses of heavy metals. The results may yield clues to unraveling the mystery of why albinism occurs
in the world’s tallest tree species.
Moore has several theories, which he hopes to publish this year. Much work yet needs to be done, but he’s the man to do it: he’s only 22, and with what he has already accomplished, he no doubt has a long and illustrious career ahead of him.
Speaking of careers, it’s interesting to note that certified arborist, albino redwood guru and new ACS member Tom Stapleton’s primary occupation is operating seven hydroelectric power plants for Pacific Gas & Electric. In the same vein, we might mention that forester Dale Holderman holds a patent on an improved gopher trap. Coniferites are such interesting people!
For more information: https://www.chimeraredwoods.com
Excerpt from the February 2017 Central Region Newsletter: The Coniferite. Gain access to archives of past newsletters and the National Conifer Quarterly by becoming a member of the American Conifer Society.