Efficacy and Effect of Tree Stabilization Systems On Landscape Tree Growth and Establishment
Various forms of staking, guying, and root ball anchoring are used to prevent post-transplant tree destabilization in the landscape, but little scientific evidence exists to support this practice. This experiment tested the efficacy of three generic tree stabilization systems (TSS) and their effect on tree growth and establishment.
In spring 2006, 48 balled and burlapped, 6.4 cm (2.5 inch) diameter, white ash (Fraxinus americana L. Autumn Purpleâ ) were transplanted to a field site in Blacksburg, VA. At planting, one of four TSS treatments (staking, guying, root ball anchoring, or non-stabilized) was installed on each tree. After five weeks, tree pulling tests were conducted on 24 trees to simulate a strong wind load using a cable winch mounted to a skid-steer loader. After one growing season, change in tree height, trunk diameter, and trunk taper were compared among the 24 remaining trees. Soil cores were taken and the length, diameter, and dry weight of roots within the cores were analyzed. TSS were then removed and tree pulling tests were conducted using the same method.
The five week tests showed that destabilization was significantly greater for non-stabilized trees (mean of 16 degrees from vertical) than for trees with TSS (all means less than 3 degrees from vertical). Yet after one growing season, there were no significant differences among any treatments in tree stability. We conclude that in locations with high wind speeds, TSS may be necessary for trees similar to those in our study, but only for a very short period of time.
Results also indicated that staking, guying, and root ball anchoring were equally effective, very robust, very durable, caused no tree injuries, and did not impact tree growth or establishment after one growing season. Practical considerations may therefore play a more important role when choosing which TSS to use. Although the time required for TSS installation was similar for each system, staking was more than twice as expensive as guying or root ball anchoring.