Fertilization & Soil Health
Trees growing in urban areas and yards typically live much shorter lives than trees growing in natural settings. Some research shows trees only live to be about 10 years old in very difficult downtown settings. What makes urban sites and yards such stressful places for trees to grow?
- Restricted root space: Building foundations, streets, driveways, and other obstacles limit the expansion of tree roots and significantly reduce the amount of water and minerals available to the tree.
- Compacted soils: Urban soils are usually compacted from human activity, and this creates stress for a tree. Soils can become difficult for roots to penetrate, and compacted soils hold much less water and oxygen which are critical for tree health.
- Competition: Most yards have a dense layer of turf that surrounds a tree. Turf aggressively competes for minerals and water, which reduces their availability to other plants. Adding 2-4 inches of mulch within the dripline of the tree reduces competition with turf, keeps the soil cooler, and holds more moisture. Basement foundations, driveways, utilities and streets restrict the root system and limit available resources. In the urban environment grass competes with trees for water and minerals. This significantly reduces the capacity of a yard to support a tree.
Healthy trees start with healthy roots... and healthy roots require the proper environment. Our goal is to replicate the "forest environment" to create soils and root environments that are self-sustaining. For trees in urban and suburban soils, or Certified Arborists & PHC Experts can simulate the optimal conditions for growth found in nature.
Our Root/Soil Toolbox
We off a variety of formulas and application methods to address the nutrient requirements specific to your landscape. In most cases these formulas are accompanied with rhizo-bacteria to initiate microbial activity and promote renewable fertility. Combined with a soil surfactant and implemented with state of the art soil injection tools, the root zone is aerated and fed simultaneously.
Mychorrhizae are tiny fungal filaments that work symbiotically with plant roots to help them absorb more moisture and nutrients. They also release enzymes which help breakdown nutrients into forms more easily utilized by the plant. Mychorrizae occur naturally in the natural environment, but urban soils are seriously lacking. When re-introduced to the root zone it will help your tree tolerate drought, pH extremes, soil salinity, compaction, and infertile soil.
BOOST (Best Option Organic Soil Treatment)
Our BOOST formulas contain a mixture of composted plant materials (no byproducts) formulated to create soil conditions similar to those in a forest. This mixture is combined with biochar, a specialty charcoal made from woody material and used as an amendment to improve soil quality. The biochar surface is filled with water and nutrients during fertilization, natural rainfall and plant decomposition. The bio-char acts as storage, holding that material until the plant roots need it. Urban soils are often compacted, low in oxygen, poorly drained, and low in organic matter. Natural organic matter cycling is disrupted in most urban soils. Soil nutrients in urban sites are difficult for the tree to utilize. Do to the poor growing conditions, a tree in the urban setting typically has 1/3 the stored energy of a tree growing in a natural forest. We have formulated organic matter prescriptions to meet the needs of trees of any age or species. We assess many variables to determine which prescriptive treatment is most appropriate for each tree. The key variables are tree condition, tree age, soil fertility, and soil compaction. Based upon these assessments we prescribe the appropriate BOOST Formula. Application process is specific to each tree, but commonly used in conjunction with our Root Enhancement Plans.
We offer a variety of treatments to both encourage root development, as well as prevent root encroachment beneath sidewalks and driveways. Homeowners frequently ask about treatments to eliminate surface roots of trees especially in lawn areas. Certain species, such as red maple, birch, and elm are inherently shallow rooted and more prone to producing surface roots. Surface roots are more common in heavy clay soils compared to sands or loams. Frequent light irrigation also can increase the likelihood that trees develop surface roots. Once surface roots become a problem, there is little that can be done to correct the condition. Cutting the roots can impact tree health and stability and roots are likely to grow back if the plant survives. Most trees species will tolerate covering the offending roots with a few inches of loam soil but as the roots grow in diameter, they will reappear on the surface. If soil is added, make sure it is not placed on the root collar and against the stem. The best option for dealing with surface roots is to mulch the area beneath the tree crown to avoid conflict between tree roots and turf.
Root Enhancement (With BOOST)
Urban soils are under constant stress and become compacted from construction and other activities. Trees planted in urban areas face many challenges that reduce their ability to grow and remain healthy. Lawns, building foundations, pavement, landscaped areas, and other obstacles limit a tree's ability to absorb water and nutrients. Trees living in compacted soils are smaller and die at a much younger age if compaction is not treated. In addition, many trees are not planted properly and have developed circling roots (SGR's) restricting efficient vascular function. If these are not corrected, the tree essentially chokes itself as the growing roots circle the trunk.
We have developed a response to these stressors that promotes root growth and improved tree health. While we cannot replace all of the soil under a tree or replicate forest soils in an entire yard, our Root Enhancement Plans can create the perfect growing environment around the base of the tree where a large concentration of roots lie. The process allows us to examine the root flare, prune restrictive roots, and integrate organic matter recipe that is right for your tree. This is a 3-step process:
Step 1. Root Collar Excavation & Evaluation: Roots around the base of the tree are exposed by forcing high-pressure air into the soil with a tool called the Air Spade removing the soil without damaging to the root system. This allows the arborist to assess the root health. Viability of the tree and chances of success are judged by several factors: depth of the root flare, number and size of girdling roots, and severity of compression of the trunk. If the examination process reveals that the tree is a candidate for our Root Enhancement System, we will proceed with the following steps.
Step 2. Treatment of Girdling Roots: Girdling roots may be pruned/cut to release compression of the trunk causing damage to the tree. Care will be taken to remove the restriction without adversely affecting the supply function of the roots.
Step 3. Application of Organic Matter: Roots within a foot radius of the trunk are exposed using the Air Spade. Turf grass within this area is removed to facilitate the process, and reduce competition for resources. A large volume of soil is loosened from its compacted state with the action of the Air Spade. Roots in the loosened area are covered with the applicable BOOST formula. The Air Spade is used to mix the organic material into the existing soil. A 3-4" thick layer of shredded hardwood mulch is placed over the treated area and saturated with water. It is critical to keep the soil in this area watered to maintain a moist soil environment.
Please note: It may be determined after step 1 that the root girdling is too extensive. At this point you would only be charged for Step #1.
What is Biochar?
Biochar is a specialty charcoal made from woody material, used as an amendment to improve soil quality. Charcoal has a long history of use for its ability to absorb and remove odors and toxins. When used as a soil amendment, it provides numerous benefits, including water and nutrient retention. We have added biochar several of our tree nutrition plans and to our Root Enhancement System.
Why use it?
Adding Biochar Enhances Fertilization Biochar particles have very large and absorbent surface areas, providing sites that water and nutrients can adhere to. This helps sandy soils hold more water, and opens up space in clay soils for root growth. Fertilizer applications are more efficiently used when combined with biochar, since the nutrients are held in place for tree roots to use rather than getting leached away by rainfall. The biochar surface is filled with water and nutrients during fertilization, natural rainfall and plant decomposition. The biochar acts as storage, holding that material until the plant roots need it. Urban soils are far from optimum for healthy tree growth. Low organic matter is one of the main problems in urban soils. Compaction, pollution, and nutrient deficiencies are other drawbacks to soil in urban areas. The addition of biochar makes the soil friendlier for tree roots and other organisms that contribute to tree health.