Sun Exposure or Insolation

High insolation results in heat and moisture stress to the seedling and can cause mortality. Insolation is most likely to damage seedlings on drier habitat types and on south- and west-facing slopes. Direct heat to the tree crown affects the tree's physiology, causing water deficits. Heat at the soil surface can raise soil temperatures to lethal levels to the seedling's stem at the soil surface. Early season insolation also can cause the seedlings to break dormancy too soon, allowing them to be damaged by freezing. All of these types of damage become more serious on exposed slopes steeper than 30 percent.

Different types of material may be used to create shade, diminishing the effects of high insolation. These materials include:

• Live trees or Brush
• Standing Dead Trees or Brush
• Stationary Shade
• Portable Natural Material for Shade
• Portable Manmade Materials for Shade

Live Trees or Brush

Live shade can protect seedlings. Select planting spots that minimize moisture competition with the live shade plants. Plant the seedlings where they will be protected from the afternoon sun.

It is generally beneficial to plant near the root crown of brush, because the roots of shrubs are not as dense there as they are farther away from the crown. Trees placed near the root crown also are protected from browsing animals. When planting seedlings under a tree overstory, it is generally desirable to plant the seedlings outside the drip line of the neighboring tree's canopy where the tree will provide shade from the afternoon sun.

Planting within brush fields is risky. In a year with good moisture, newly planted trees may survive. If moisture is not good the following year, seedlings may die because the brush will have a competitive advantage for moisture. Rodent damage can be more common in brushy areas. (top)

Standing Dead Trees or Brush

Shade from standing dead trees and brush can protect seedlings, but planters have difficulty moving in dense thickets of dead brush. Falling debris may smother or damage young seedlings. Standing dead trees may fall unexpectedly, presenting a hazard to tree planters. (top)

Stationary Shade

Stationary shade provided by stumps, rocks, and larger logs is the best site protection. On south and west slopes, plant seedlings on the north or east sides of the stationary shade to protect the seedlings from afternoon sun. Downed logs, stumps, and large pieces of debris provide dead organic material that is ideal for microsites. During logging and site preparation, leave enough debris for shade materials. Root pathogens may spread from stumps to the seedlings. In areas where root pathogens such as Armillaria spp. are a known problem, do not plant adjacent to stumps. However, on most forested sites, the benefits of planting near stumps (shade and protection from trampling) outweigh the risk of mortality from disease. (top)

Portable Natural Materials for Shade

Pieces of wood or branches larger than 3 inches in diameter, rocks, and other material can be used for shade. Place the shade on the south and west sides of the seedling, to offer shade in the afternoon. Rocks should not touch the seedling. (top)

Portable Manmade Materials for Shade

Staked shade cards or shingles are expensive to purchase and install, but are an option where there is no natural shade. Although it is beneficial to shade the entire crown of the seedling, the most critical area needing shade is at the ground line where insolation may raise soil temperatures above lethal levels.

Artificial shade should not be needed on most sites where logging and site preparation have left enough debris. Examples of artificial materials that can be used for shade include wood shakes, fiberboard stapled to wood, plastic shade tubes, black plastic net material with wire supports, and Styrofoam cups (coffee cups).

The costs of using artificial material to create shade depends on the type of material and the ease of installation. Staked fiberboard and cedar shakes are usually cheaper to buy, but more costly to install, especially in rocky soils. Styrene cards and black mesh shade cloth systems are generally best for rocky soils.

The color of shade cloth or the size of the mesh opening is not important. Both black plastic nets and styrene nets can be installed easily with wire prongs that cause less root damage during installation than stakes or shakes.

On sites with artificial shade, check the materials in the spring. Straighten or reinstall materials that have been knocked out of place by animals, snow, or other disturbances. Otherwise, the shade materials may end up covering the seedlings rather than shading them.