It’s been a busy spring around the Cregg lab. In many ways, it feels more like mid-summer than mid-May. One of the items my students and I have been with is installation of the Social Media Designed Tree Transplant Study (SoMeDedTreeS). As loyal Garden Professor blog readers will recall, we conducted a Survey Monkey poll last fall to help develop a study plan to investigate tree transplanting practices of container-grown trees. Based on the results of the survey we designed a study to look the effects of root-ball manipulation and post-transplant fertilization on 96 planetrees.
Well, the time has arrived. Last week we completed the first of two installations of the study – the second will be installed at the MSU Beaumont nursery soon. Graduate research assistant Dana Ellison and summer research intern Aniko Gaal finished planting the first 48 trees last week at the MSU Hort Farm. These two did yeoman’s (yeowoman’s?) work in handling the trees, applying the treatments and getting in the trees in the ground.
Sometimes the best man for the job is a woman…
All of the trees are ‘Bloodgood’ planetrees that we have grown on in 25 gal. containers for past two years. The study was installed as a 3 x 2 factorial in a complete block design. We have 3 root-ball manipulations: “shaving” the outer 1 in. of the rootball to remove circling roots; “teasing” apart the outer part of the rootball to pull appear circling roots; and “control” just pop off the container and drop ‘em in the hole. The second part of the design is fertilization; with or without. This results in 6 combinations (3 root-ball manipulations x 2 fert levels) times 8 reps = 48 trees total.
Graduate Research Assistant Dana Ellison teases apart a root-ball
Summer Intern Aniko Gaal shaves a root-ball. Step one: remove the ‘pancake’ of roots from the bottom.
Not to complicate life too much but I am considering a change to the protocol. We will continue with the original rootball manipulation and fertilization trial at the second installation at Beaumont nursery. In each test we would have 48 trees and 8 reps, which is better than a lot of landscape tree studies. But given our recent discussion about mulching, I propose substituting with a mulch vs. without mulch treatment instead of the fert vs no fert at the Hort Farm installation. We will water the trees once or twice a week to help get them established and then cut off the irrigation after about a month (simulating a city forestry department getting a budget cut and having to lay-off its temporary crews). We will monitor soil moisture and tree water status in the subsequent months.
Trees after planting
Before I make the change in the study, however, I’d like to get some feedback from our readers lest anyone feel there’s been a bait and switch.