Innovative Approach to Site Preparation Saves Time, Money

Weyerhaeuser has developed a faster, less expensive, and environmentally superior approach to preparing land in our southern forests for tree planting.

The traditional approach to preparing the ground in southern forests involves four steps, each requiring a separate labor expense:

• Shearing stumps and removing debris to provide a clear area for planting
• Tilling the soil so seedling roots can move through it more easily
• Fertilizing
• Applying herbicide to prevent other vegetation from overgrowing the seedlings

Herbicide is typically applied from the air—a more costly process. Aerial application carefully targets the herbicide to avoid lakes, streams, and neighboring land, but is limited in its ability to pinpoint the herbicide to the parts of the acre where it is most needed.

"We have a real breakthrough with this one," says Ken Durand, early-rotation leader for Southern Timberlands. "The new approach can combine several steps and take precision application of herbicides to a new level."

After stumps and debris are removed, a specially equipped vehicle accomplishes the remaining work in one pass:

• As the soil is tilled, liquid fertilizer is injected underground, right where the seedling will need it.
• A narrow strip of herbicide is applied to prevent grass from sprouting in the row where seedlings will be planted.
• To give the seedlings room to grow, herbicide is also applied outside the row in an area no wider than necessary.

The Southern Timberlands early-rotation team, working with the southern research and development group, began developing the new approach in 2005.

"We were challenged to reduce our costs by $5 million," says Durand. "This approach not only helped us reach that goal but also is better for the environment. It's possible we could use 40 percent less herbicide because we apply it more precisely."

Combining these site-preparation treatments makes Weyerhaeuser unique among southern timber growers, says Durand, partly because of the company's unusual approach to planting in the south.

"Weyerhaeuser is the only company I know of that plants trees in widely spaced rows," he says. "The spacing creates the opportunity for precision application of fertilizer and herbicides."