OLD GROWTH TREES

Archangel "Champion" Sequoia Clones

 

How does one clone a tree? Some plants naturally reproduce asexually, which means, technically, their offspring are clones (PNW, 2011). In horticulture, grafting is one of the oldest and most common ways to clone. The major objective of grafting is, “to multiply plants identical (true-to-type) to the parent plant” (PNW, 2011). If there is a plant that has a specific or rare trait someone wants to replicate, cloning is the one way to guarantee multiplying that trait. 

 

Grafting is accomplished by “inserting a piece of stem containing 3 to 4 vegetative buds onto the stem of the plant that will serve as the root system for the unified plant. In nature, two closely related plants growing in proximity may establish a graft union [literally, grow their tissues together] on their own” (PNW, 2011). Milarch and his team tried this technique repeatedly in their early days attempting to clone their colossal (and thus ancient) trees, but to no avail (Robbins, 2012). This is because plants’ ability to develop roots declines with age (PNW, 2011).

 

Many critics doubted that Milarch would ever be able to clone one of his “champion*" trees due to their age (Robbins, 2012). But Milarch persevered. Using micropropagation, a modern way to clone plants, he and his team eventually succeeded in cloning Redwoods over thousands of years old (Robbins, 2012). Micropropagation is a complex process based around simulating entire new root and stem growth from tissue obtained from the meristem of plants through the use of nutrients and hormones (Robbins, 2012; Korrban & Sul, 2007). The process starts by placing meristem tissue in a special culture where hormones and nutrients will stimulate new shoots. Each shoot is then placed in a second growth medium with more hormones and nutrients. Here they grow until they are about an inch long before they are transplanted to soil in a climate controlled greenhouse. After a year or so, the clones will be close to six inches tall and ready to be planted in special soil mixtures (Robbins, 2012; Korrban & Sul, 2007). (A diagram of the process is found below) The meristem of a single tree can produce tens of thousands of clones through micropropagation, allowing the cloning of these trees to become economically viable (Robbins, 2012).

 

Sources Cited:

1. Robbins, Jim. The Man who Planted Trees. New York: Spiegel & Grau, 2012. Print.

2. Pacific Northwest Extension Publication (PNW). Propogation of Plants by Grafting and Budding. Washington State University: Pacific Northwest Extension Publication, 2011. Print.

3. Korban, S. S., and Sul, I.-W. “Micropropogation of Coast Redwood.” Protocols for Micropropagation of Woody Trees and Fruits. Jain, S.M., and Häggman, H. Springer, 2007. 23-32. Print.

 

*A "champion" tree is a designation given by Archangel to a tree with "the highest combined score of three measurements: height, crown size, and diameter at breast height" (Robbins, 2012).