OK, the results are in for our reader poll to design a landscape tree transplant study here at MSU next spring. And the winner is…er, I mean, winners are: Root ball manipulation and Fertilization at the time of planting. Root ball manipulation drew 74.3% of the responses, Fertilization was chosen by 63% (voters could chose more than one favorite topic). All other proposed topics were under 40% (Mycorrhizae – 37%, Crown reduction- 31%, Cambistat – 11.4%, Bioplex – 11.4%). I will put pencil to paper and survey the trees and space available for a trial. My initial thought is that we can do a 3 x 2 factorial experiment with 3 types of root-ball manipulation and 2 levels of fertilization. Root-ball manipulations will include two popular recommendations: 1 – ‘shaving’ the root-ball to remove circling roots; 2 – ‘teasing’ the root-ball to untangle circling roots; and 3 control e.g., planting the root-ball as is. The two fertilizer treatments will be 1 – 400 grams Osmocote and 2 – control, no fertilization. The goal is for this to a long-term study – hopefully at least 5-years. The principal response variables will be survival and growth. If time and resources allow we will collect water relations data such as water potential and stomatal conductance during the transplant year.
I was a little surprised that Cambistat did not rate higher. This product has been heavily marketed to arborists and has been touted to reduced transplant stress. The active ingredient, paclobutrazol, is a well-known plant growth retardant. The theory is that it reduces stress by limiting crown expansion and reducing stomatal conductance while roots continue to develop. I’ve actually been a bit intrigued and may set up a little side study to satisfy my own curiosity.
Thanks to all who took the time to vote. I look forward to keeping you all posted on the trials!