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.