Reforestation 101

Spring 2006


We’re all familiar with the old adage about a chain being only as strong as its weakest link. This rings especially true when discussing reforestation. Many steps must be completed to ensure a successful planting project, and failure to properly address any step will stack the cards against obtaining a new, vibrant forest. Here is a brief overview of critical reforestation elements.

Site Preparation

Planting failure usually relates to inadequate site preparation. Without prudent site preparation, you will be lucky to achieve a five percent seedling survival rate in areas with significant competing vegetation, which is notorious for starving newly planted seedlings of critical moisture and sunlight. Grass is particularly effective at using all available soil moisture, while brush or larger trees can shade-out seedlings.

The best method to reduce competing vegetation depends on many factors, including tree species to be planted, site characteristics, and type of competing vegetation.

If a site contains thick and tall brush (over four feet in height), mechanical removal prior to planting is the best approach. This is necessary because it is very difficult to find planting spots in dense brush. Treatment can be accomplished by using a cat equipped with a brush blade or an excavator (large tracked backhoe with a bucket and thumb). It is critical that soil disturbance be minimized, so use of an excavator is preferred. When mechanically removing competition, it is acceptable to leave a portion of the brush intact to improve soil stability and reduce site preparation cost.

Following mechanical treatment of brush, an herbicide application is normally recommended. Herbicides are usually the most efficient and cost-effective method of treating competing vegetation, and when properly applied, they provide safe, long-lasting vegetation control.
Matching the best herbicide and application technique to your site conditions is vitally important. Although it is outside the scope of this article to discuss herbicide use in detail, we will briefly highlight a few common approaches. To simplify matters, most of this information relates to situations where tractor or helicopter application is impractical.

The ideal method is to complete all site preparation activities, including herbicide application, in the year prior to planting. Unfortunately, this may not be feasible due to log market changes, scheduling conflicts, vegetation type, etc. Consequently, herbicides are often applied during or after planting.

When planting ponderosa pine, Pronone is very effective. This granular herbicide can be applied with a “weed-a-meter” device, during planting, in a five-foot diameter circle around the seedling. The chemical will control grass, as well as brush species, and reduces competition for about two years. It also has the side benefit of stimulating the growth of ponderosa pine beyond the boost from reduced competition. However, other tree species have varying degrees of susceptibility to Pronone, so it is best to restrict its use to ponderosa pine.

Different tactics must be employed if western larch or western white pine are planted. A common approach is to use Accord (many people refer to this chemical as Round-up), which will kill grass and many brush species. For Accord to be effective it must be applied on actively growing vegetation. Since vegetation is usually dormant during planting time, the herbicide is usually applied a month or two after planting.

In the spring, seedling needles are susceptible to Accord, so they must be protected during application. We often apply the herbicide with a back pack sprayer and use a stove pipe to shield seedlings. Due to the fact that this chemical is inactive in the soil, it does not damage the seedlings if applied in this manner. The challenge is finding the seedlings after other plants grow and begin to hide them.

Depending upon your specific situation, there are additional herbicides to consider. Some examples commonly used in our area include Oust, Arsenal, and Velpar (liquid Pronone).

Regardless of the herbicide selected, carefully follow label instructions and be sure to have the appropriate applicator’s license.

Animal Control

Here’s the wild card in the reforestation world. The impact of feasting critters, such as gophers, mice, deer and rabbits, on your trees is hard to determine.

We have learned some hard lessons on how tasty seedlings are to rodents. If gophers or mice are a potential problem (and they usually are in grassy settings), then steps must be taken to deal with them. Early in our career, we had situations where gophers ate 95% of the seedlings planted in fields. Fighting these critters is a challenge, but there are schemes to minimize their damage. Again, discussing all aspects of rodent control is outside the scope of this article, but if it appears these varmints are present where you plan to plant, it is advisable to acquire expert advice.

For deer or rabbit problems, a protection tube can be placed around the seedling. These items are not cheap, but if properly maintained, they are generally effective in minimizing damage. Repellant sprays are another viable option, but they must be reapplied, which increases costs and inconvenience.

Seedling Selection

To ensure the long term health and vigor of your forest, proper seedling selection is critical. Which species to select depends on your forest characteristics, but keep in mind that planting a variety of species will help maintain forest diversity. Western white pine (partly blister rust resistant), western larch or ponderosa pine are commonly planted because they are less susceptible to most significant pest problems. In addition, they generally constitute a small percentage of young trees in many forests, because they are sun-loving and need specific site conditions to become established.

Seedlings can be purchased from numerous sources, but it is vitally important to select seedlings that have been grown from seed collected in areas similar to your property. Elevation and proximity to your land are the two main items to consider. Transfer guidelines differ by species, with white pine being the most flexible. Please contact IFM for assistance locating suitable trees for your site.

Planting

Finally, after considering all the previous factors, it is time to plant. I bet you thought we’d never get to this point! For many people, tree planting is the most satisfying of all forest management activities. It is hard to beat the pleasure of watching those baby trees grow!

Here are a few guidelines:

  • In our area, family forests are typically planted in the spring. It is best to plant as soon as possible after soil temperatures reach 40 degrees, which is when seedlings’ roots will begin to grow.
  • Seedlings must be planted with straight roots and at the proper depth.
  • It is beneficial to plant trees on the northeast side of stumps, or other debris, to help shade them from the sun.
  • The number of trees to plant depends on many factors. Usually 300 to 440 trees per acre are planted. At this planting intensity, spacing between trees will range from 10 to 12 feet. During planting it is more important to focus on using the best planting spot (less competing vegetation, near a stump, etc.) than having perfect spacing.

Please understand that this article is meant to be a brief overview of planting techniques used in our area. Be sure to contact our office or another professional forester to acquire specific information for your project.

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