If you have a few large trees on your property, then you probably are obsessed with assuring that they are healthy in both the short and long term. Some in the field of horticulture and arboriculture favor the use of root watering/aeration tubes for promoting healthy root systems of trees. They argue that this tool helps to improve soil conditions as well as oxygen levels, air space and water content of the soil where the tree is planted.
There is a consensus among horticulturist and arboriculturists that root watering/aeration tubes can be beneficial in certain circumstances.
You probably are aware that the plant root zone of trees is filled with soil mixes that are vital to root and plant growth. These mixtures include water, nutrients and oxygen. When there is an absence of one or more of these ingredients, then the health of the root system is adversely affected.
The soil must have a minimal and maximum amount of these ingredients for the tree roots to be healthy.
ROOT GROWTH RESOURCE REQUIREMENTS
The table above is a general breakdown of a few of the soil requirements for root growth. A detailed description of nutrient requirements is located here.
Because of the loss of modern urban forests, most urban soils have been moved, replaced, contaminated, and subjected to high levels of compaction due to limitation of space for rooting, limited soil gas exchange, obstructed drainage and composition variables. In these types of conditions, the average life span of trees is estimated to be just 10 years. That’s because soil compaction reduces open pore spaces in the soil and this restricts root growth due to limited access of quantities of needed nutrients. In addition, high clay content and high-density plantings or grasses in the vicinity of trees also limit soil conditions. Turf grasses, the use of water, air and nutrients in the upper soil absorb the nutrients before they can reach the tree roots. As a result, tree roots stay close to the surface where they can compete for resources.
Benefits Of Root Watering/Aeration Tubes
Several studies have been done on root watering/aeration tubes to ascertain whether or not they are effective in improving the health of the root system of trees. These tests have shown that these tubes do have benefit.
First, these tubes that feature mesh have a high permeability that assists gas and water exchange in the soil. So they are more effective than tubes that don’t include mesh. Moreover, a study performed by Davey Tree Research Station showed that mesh tubes are good to use in areas where there is hardscape, like concrete.
Tests have also shown that trees grown with the assistance of these tubes grew 48 percent more roots in the lower half of the tree’s root ball after only three months of establishment. Roots in the upper soil profile performed equally. After 13 months of establishment the same trees produced a total of 18 percent more roots than trees irrigated by a drip system.
Moreover, a consensus of the studies showed that the tubes were most affective when used in compacted soil with slow draining characteristics or where surface vegetation is dense.
The tubes that worked best had these characteristics.
- The soil was able to conform to the tube with as much surface area as possible. The more surface area, the better.
- The tubes had a high permeability or included a mesh or were highly perforated allowing the highest rate of water/gas exchange.
- The tubes were very strong allowing them to avoid collapse when being installed or due to pressure from surface elements like cars and construction equipment.
- Perforated tubes with reinforced locking lids were able to combat attempts at vandalism and premature filling .
It should be noted that water from the tubes must be applied at the surface of newly planted root balls and the root balls must be kept moist to encourage growth. Water should be run long enough to fill the tube and the soil well at the surface.