SOIL -- BEYOND JUST DIRT

Why do trees need good soil?

1. Structural support
2. Nutrients
3. Water
4. Oxygen

Image :http://wiki.ubc.ca/

The roots of trees are in the top 6 to 9 inches of soil. In the forest trees receive the four things listed above naturally. In an urban environment good soil is hard to find. In most urban sites I have found compacted soil, soil that has been leached of all the nutrients, or sites that have had all the top soil stripped away.



Soil horizons


O horizon-  Organic material- made up of leaves, wood breaking down, worms and insects.


A horizon-(top soil)  Mix of organic and mineral matter- made up of iron, clay, aluminum, and organic compounds.


B horizon- Sub soil-  made up of iron, clay, and aluminum.


C horizon- Parent rock- large pieces of rock.


E horizon - Bedrock 


In central North Carolina the A horizon is slim to none. If you have tried to dig in your yard in central NC you have seen the maybe inch of O and A horizon on top of hard red NC clay (B horizon).

Soil sample showing the O horizon, A horizon and B horizon. Sample was taken from a wooded area in central NC.

Soil elements and pH levels

The elements found in soil for a healthy tree are:

Primary- 

• Nitrogen-N
• Phosphorus- P
• Potassium-K 

Secondary-

 

• Calcium - Ca
• Magnesium- MG
• Sulfur- S

Micro nutrients- 

• Boron 
• Chlorine
• Cobalt
• Copper
• Iron
• Manganese 

For the best absorption of nutrients into the roots of trees the soil pH should be between 6.2 and 7.3.
 

Saddleback Caterpillar

Saddleback Caterpillars are found in late summer and early fall in the eastern US. These caterpillar feeds on a large variety of plants and trees. The caterpillars have spike like hairs that pack a punch with irritating venom.  I found the one pictured above on my hopps in my back yard.

Dogwood Anthracnose

Field notes - Northern Red Oak

Northern Red Oak
11" DBH
25' H

Diagnosis-

1. Oak skeletonizer
2. Fungal canker
3. Environmental stress

Oak with internal section die back.

  Signs of an Oak Skeletonizer

•  Leaves are rolled and stuck together in a type of nest.
• Inside the leaves are a yellow worm like caterpillar.
• Leaves are stripped leaving only the veins.

Nest from an Oak Skeletonizer

In the center is an Oak Skeletonizer

Oak Skeletonizer

The stripped leaf from an Oak Skeletonizer.

A nest from an Oak Skeletonizer

• The under side of the leaves are covered in the eggs of the Oak Skeletonizer.

Signs of an oak fungal infection

• The bark at 10' to 15' has lichen and moss. 
• At 3' is a oozing fungal canker.
• Internal die back.

Signs of Evironmental stress.

• The leaves falling off the tree. 
•  Piping for irrigation cut to close to the base if the tree.
• Ground cover absorbing nutrients and water needed for the tree. 
• The soil was very dry. 

Treatment-

• Oak Skeletonizer- spray with Bifenthin (Talstar)
•  Fungal Infection - Basal injections of Reliant
• Enviromental stress- Fertilization, Aeration and Vertical mulching.

Armillaria Root Rot in Pin Oak

I recently examined a Pin Oak 45 feet high and 13 inches DBH. This tree had wilted misshapen leaves with some leaves on the ends of the branches that were over sized and misshapen.

The bark had small off white mushrooms (2mm)  in patches coming from cracks in the bark.

The soil was very moist with moss covering it. There were small yellow/ gold mushrooms growing from the soil at the base of the tree.

Diagnosis- Early stages of  Armillaria Root Rot

Treatment - Aeration and Canopy thinning

Pesticides - No known effective fungicides. Relaint systemic fungicide can be used to prevent any further fungi.

Call me the Tree Doctor

Recently I became a licensed pesticide applicator for North Carolina turf and trees. I like to think of my self as a tree doctor. I am sent to trees that are sick and diagnose them, whether it be from insects or fungus. This time of year Leyland Cypress (Cupressocyparis leylandii) can become infested with Bagworms. The proper treatment for this is to spray the infected trees with Basilis thuringiensis. This is also a treatment for spring Eastern Tent Caterpillars and Fall Webworms.

                                      
For the treatment of trees that are out of reach, such as a Pignut Hickory (Carya glabra) that I recently diagnosed with fungal Root Rot and Brown Leaf Spot fungus. Where in this case I needed to treat the foliage which was 70 to 100 feet up I used an basal injection systemic fungicide.