Seedling Compass

Tim Eck is a very active volunteer with the The American Chestnut Foundation - an organization every tree person should join. On a LISTSERV or mailing list for TACF, Tim asked the following question:

In another list site, the concept of solar polarity arose. Some horticulturists believe that you should mark the (compass) orientation of a tree before transplanting so the orientation can be retained upon transplantation.
While I find it difficult to believe that a one year seedling would be set back due to "disorientation", I might believe it for a more typical nursery size. People also pointed out that when they have a plot of distichous plants or bulbs, they noticeably orient with the compass points.
Any comments or experiences?
Tim

My answer to Tim follows:

Where I have run into the recommendation to retain the polar orientation when transplanting, it was to prevent frost cracking in thin barked species such as maple. As I recall, the theory is that the bark has somehow developed strength and/or elasticity to accommodate the expansion and contraction that occurs on the sides that are exposed to the sun. Whenever I have seen a frost crack dissected, the crack has always started at a wound site and propagated from there. Dr. Larry Severeid has some pictures illustrating this in black walnut.

Also I have only seen this recommendation for sapling sized trees and never for 1-0 or 2-0 seedlings. Bareroot seedlings are always planted randomly and I see no meaningful benefit from maintaining the orientation except one. A very important reason. The act of maintaining the orientation will require the grower to handle the plant very carefully. Handling plants carefully matters hugely. I remember visiting a planting where the grower claimed extraordinary growth by playing music on large speakers in the plantation. What I was a plantation with an exemplary degree of husbandry. The weed control was perfect. The fertilization was a secret (and very expensive) mixture frequently and carefully applied. Plants respond to care. Those who play music for their plants also notice when they need water. They see the bugs before it is too late.

Bottom line: Don’t worry about the orientation of a seedling, but the growers who do will have better trees – for the reasons above.. ;-)