A Picture Tour of Black Walnuts

Dr. Walter Beineke, a leading authority on the genetic improvement of black walnut discusses grafting techniques with Norman O'Bryan, president of American Forestry Technology.

The fact that black walnut is one of the most difficult species of trees to graft makes greenhouse management crucial to the success of the entire program. Dr. Beineke's expertise in seeing to it that the grafts flourish both in the greenhouse as well as in the plantation setting is invaluable.

Mr. O'Bryan has grafted and supervised the grafting of more black walnut cultivars than anyone in the business. His ability to bring all the necessary ingredients of successful grafting together is unparalleled.

Although grafting black walnut is problematic and costly, the years of Dr. Beineke and Norm O'Bryan working together have paid off with viable Trees.

Production manager Sean O’Bryan inspects Successor GST grafted trees in one of AFT’s greenhouses.

Sean oversees the process of producing the grafted trees. The process begins with the collection of scion wood from the parent trees after they’ve gone dormant. The scion wood is then sorted by size and stored in a cooler.

At the same time, root stock is planted in potting soil and set in the grafting lab under special growth-stimulating lights. When the sap begins to rise, the scion wood is grafted onto the root stock. The resulting graft remains under the lights until early Spring when it is moved into one of the greenhouses.
Sean displays one of the grafted Successor GST clones.The graft union can be seen just in front of Sean’s thumb.

Grafts are made by "splicing" the scion wood to the root stock. AFT uses the finest root stock available, the seedlings grown from the nuts of the parent trees.

Even at this early age, the veneer-grade form for which these trees are noted, is already evident in the straightness of the mainstem.

Growers who are successful continue to provide the trees with the kind of high-quality care that’s provided in the grafting labs and greenhouses

This Successor GST is beginning its third year. It displays the GST’s well-documented genetic tendency for the mainstem to grow straight to the very top of the tree without any assistance from surrounding plants.

Most trees that display superior form in the forests do not display that form when planted in a plantation setting. What makes trees in the forest grow straight is their proximity to other trees and the fact that sunlight filters in through the canopy. Phototropism (the tendency for a plant to grow towards the light) overcomes the genetic tendency to fork.

Planting trainer trees is expensive and slows the growth of the black walnut trees, and with the genetically-improved Successor GSTs trainer trees are not necessary.