Urban Soil Management & Remediation
Trees at Risk
Any urban tree is at risk for poor soil conditions. Over 50 percent of a tree’s living tissue is found below the ground. The active roots, those providing the vast majority of a tree’s water and nutrients, are located primarily in the top 12” of soil. Urban soils are often compacted, low in oxygen, poorly drained, and low in organic matter. In addition, factors such as construction damage, soil compaction, competition from turf grass, and other human activities can greatly impact the health of roots as well as the health of the soil itself.
Natural organic matter cycling is disrupted in most urban soils, and soil nutrients in urban sites are difficult for the tree to utilize. As a result, urban trees live an average of 1/4 as long and have 1/3 the stored energy of a tree growing in a natural forest area.
The productivity of any urban soil is determined by the site characteristics (soil texture, structure, drainage, etc.) and the quality of the organic matter available for decomposition. Many urban soils are not well suited for tree root growth.
Symptoms of Damage
- Chlorosis (yellowing of the leaves)
- Dieback from the top of the tree
- Early fall color
- Sprouting or suckering from base of the tree
- Decay near base of the tree
- Reduced twig and branch growth
- Stunted leaves
- Weakened or thin canopy
Poor soil can stunt leaf growth
When caring for urban trees it is important to make a complete evaluation of all environmental conditions to accurately diagnose all stress factors and prescribe care based on specific circumstances. This prescriptive care will help your tree meet its full potential. Site limitations, soil conditions, and nutritional needs must carefully be assessed to determine which practices should be performed. The primary goal is to create a suitable soil environment that promotes fibrous root growth resulting in greater capacity to acquire water and nutrients from urban soils and a healthy more vigorous tree.
The AirSpade’s® specialized nozzle forces air into the soil at 2X the speed of sound. This supersonic air ow can be utilized to reduce soil compaction, increase aeration, and incorporate organic matter into existing urban soils without damaging the sensitive roots. The AirSpade® allows the arborist to physically improve the soil structure and establish an ideal environment for tree root growth. Additionally, amendments can be incorporated into the soil based upon the results of a soil sample analysis.
Cambistat® inhibits the production of the growth hormone, gibberellin, which is responsible for cell elongation and tree growth. Cambistat® treated trees produce more abscisic acid, which has a powerful role in helping trees withstand and respond to environmental stresses.
Cambistat® also increases the production of chlorophyll. This results in trees with darker green leaves, increased fibrous roots, improved drought tolerance and strengthened ability to better withstand urban stress conditions.