In the previous post I mentioned that we wanted to screen trees for wood properties as early as possible, BUT there is a lot of “noise” with the mix of normal and reaction wood (compression in softwoods or tension in hardwoods). The main problems for running a glasshouse experiment were:
- How to separate normal and reaction wood? Here the good-old-leaning-trees approach was handy.
- Trees move a lot in real life, what’s the effect of thigmomorphogenesis (fancy name for response to movement)? How can we move them? Build a rocking machine: having good technicians help.
- How good are the screening methods? Before embarking in a big experiment, better look first in a few clones with contrasting wood properties (4 Arborgen varieties). If that doesn’t work, pull the plug.
So we got a glasshouse with four clones, some ramets standing, some leaning and some rocking for eight months (video here). Standing trees and rocking trees had random arcs of compression wood, but rocking reduced wood stiffness by 20%, which is similar to what happens to mature trees on the edge of stands. Leaning trees nicely separated normal and compression wood, which now could be analyzed separately; not only that, but they magnified the differences between the clones. TO BE CONTINUED.
Luis A. Apiolaza, Brian Butterfield, Shakti S. Chauhan & John C. F. Walker. 2011. Characterization of mechanically perturbed young stems: can it be used for wood quality screening? Annals of Forest Science 68: 407–414.