​PPDL Picture of the Week for

July 25, 2016

Using Air-Spades to Correct Root Deformations, Deep Planting, and Compaction​

Kyle Daniel, Nursery and Landscape Outreach Specialist, Department of Horticulture and Landscape Architecture, Purdue University

When transplanting trees, it is important to consider the long-term viability.  Since the life span of an urban tree is 7-20 years, proper establishment techniques are very important to decrease this abysmal mortality rate.  If a tree becomes ​established, it is much more difficult to correct below ground problems.  One method to assist in correcting these below ground issues is using an air spade.
Root deformations can occur for many reasons in established trees, but the most common are due to not making corrections prior to transplanting.  Many plants that are grown in containers have girdling and circling roots which must be addressed at the time of planting.  If this issue is not addressed many problems may ensue when the tree is established, which includes decline, tree failure, blow-overs, and more.  Air-spading is a method that can be used to correct these root deformations.
Another common problem that occurs at transplanting (and sometimes in the nursery) is deep planting.  Plants are often planted deep in the nursery for two main reasons: 1) cold protection of the roots and root flare and 2) prevent the use of staking.  In fields that are cultivated, the soil often mounds around the trees which can increase the depth of the root flare.  When transplanting trees, you should remove soil from the base of the plant until the root flare is found.  Once a deep planted tree becomes established, an air spade can be used to remove the soil to find the flare.  Many times adventitious roots will form when a tree is planted deep.  In most instances, these should be removed when spading occurs. 
Compaction can become an issue when trees are located in high traffic areas.  Compaction can be reduced by using an air spade to remove the soil from the root hairs that are typically located in the top 6 inches of soil for most trees.  
For more information on correcting root problems after a tree becomes established:

Click on image to enlarge

Figure 1
Figure 2