Posts Tagged ‘roots’

New home construction and remodeling around existing trees can lead to serious damage and in many cases mortality of existing trees.

There are a number of species which can only tolerate minor changes to the environment before they begin to decline in health and vigor. The Post Oak is one of these species. An above ground visible deterioration may not become evident for several years after the change has taken place. One of the biggest factors which typically goes unnoticed is that many of these trees have evolved on the site with the annual rainfall of 30 – 35 inches per year. Once we develop a site and add an irrigation system, the amount of moisture falling on the property is doubled. Existing trees, especially with root damage, will not tolerate this dramatic increase in moisture.

POST OAK (Quercus stellata)

The Post Oak is common in west Dallas county, Collin county, and Parker county. They tolerate little if any change within the environment surrounding their root zone. They tolerate additional moisture poorly as well as most landscape development. The Post Oak is commonly reported to die overnight. This is actually from many years of root deterioration. Many times this deterioration is accelerated by increased moisture. We attempt to improve the environment for redevelopment of the root system with deep root fertilization programs. This process not only provides a high quality nutrient solution to the root zone, but also aerates or adds oxygen to the root zone. Many times these programs may be designed to be very aggressive with a series of feedings during a season. Site conditions such as limited root area, soil compaction and tree condition will dictate which type of program your Arborist may design for your trees. Budget considerations are also a factor.

In most cases we are attempting to slow or stop the deterioration of the tree or trees. As frustrating as it may sound, in many cases we hope the trees look no worse next season. You must remember that many of these trees have developed their root system over the last 30 – 50 years. The development has within a matter of months eliminated a majority of the root system. It can take several years to visually see improvement. You must be patient.

Pruning to remove green or live tissue is NOT recommended. We believe that the more leaf area a tree has, the more usable food is being produced. Many times your Arborist may recommend deadwood removal ONLY.

Reducing the amount or frequency, or both, of your irrigation output will almost always be recommended. Many irrigation audits estimate that well over 75% of homeowners with automatic systems overwater.

It is difficult to tell exactly how much you should run your particular system because of all the variables to consider. However, we recommend to start at 3 times a week and 15 minutes per station. If your property has slope to it, it may be advisable to run the lower sections at a reduced time for the higher areas will be draining to those lower areas of the property.

We also recommend to avoid water-loving plant material (such as Impatiens, Caladiums, Azaleas, etc.) within the canopy area of Post Oaks, as these flowers will only tempt you to water more frequently.

We really do not feel comfortable with Post Oaks which have sustained root injury for several years after the impact or change. We have seen mature trees fail 10 and 15 years after development.

The following lists will help summarize this sensitivity of tree species common to North Texas:

Base Investigation and Clearing Root Flares Using the Air-spade_®

The Air-Spade is a handheld soil excavation tool connected to a large air-compressor. The high pressure stream of air is funneled through a small nozzle breaking dense soils apart into small particles. By using air to excavate soil, delicate roots, underground pipes, and hard surfaces are not damaged. Arborists can recommend using the Air-Spade for many reasons.

Air-Spade Uses

• Expose root flares of trees planted too deep
• Expose root flares of trees covered with fill dirt
• Expose root flares and root structure 6” to 18” below grade for base investigation
• Expose root flares for Macro-Injections
• Digging trenches without cutting roots or concrete

The root flare or root collar is the area where a tree begins to flare outward at ground level. This is a critical part of the tree where trunk tissue changes into root tissue. If this area is covered with soil and kept moist for extended periods of time, the tissue begins to breakdown. This leaves the tree vulnerable to root decay and ultimately poor health and vigor.

Base investigation is needed when an Arborist suspects deterioration of root tissue. Since roots can not be seen above the surface, the only way to confirm this suspicion is to excavate the soil and inspect the root structure.

Clearing root flares for Macro-Injections is another common use for the Air-Spade. Macro-Injection is an application method used to apply chemicals such as Alamo for Oak Wilt management. Soil and debris are removed quickly and easily without damage.

EXPECTATIONS OF AIR-SPADE WORK

1. Preparing the Soil Water the soil area around the tree one or two days prior to the Air-Spade work being done. This will soften the soil and expedite the process.
2. Clearing the Work Area The work area around the tree will need to be prepared. Prior to the movement of soil, we will remove any grass, ivy, shrubs, or flowers from around the base of the tree. This work area is typically one to two feet from the base of the tree. We do not preserve the vegetation in most cases and request you salvage any plant material you want to keep. We do not replace the vegetation removed.
3. Noisy Process Due to the high pressure air being used and the compressor needed, the process can be quite noisy.
4. Backfilling the Excavated Area When excavating a root flare, the void created can sometimes be quite deep. If the area cannot be left open, it can be filled with coarse mulch. When the area exposed is greater than eight inches deep, medium to large stone can be used backfill the area insuring greater air circulation around the base.