Foresters weigh options

By MATEUSZ PERKOWSKI

Capital Press

In planning a reforestation project, foresters must make an important decision: whether to use bare-root or container-grown tree seedlings.

That choice is not an easy one, since each stock type has distinct advantages and disadvantages, experts say.

For example, bare-root trees -- grown outdoors in the ground -- are generally less expensive even though they're often larger than container seedlings. The larger size makes bare-root seedlings more resistant to deer and other herbivores, which will consume most of a smaller tree, said Steve Akehurst, marketing representative for IFA Nurseries.

The downside is that taller trees are generally less tolerant of sites that are prone to drought, Akehurst said.

Bare-root trees tend to have thicker stems and more fibrous roots, characteristics that bolster growth, he said.

However, the root system can hinder the planting process, as the roots must go straight down into the ground. Twisted or bent roots will impair survival and growth, Akehurst said.

Container-grown, or "plug," seedlings are easier to plant, he said. "You can get away with things with plugs you can't with a bare-root tree."

Because bare-root trees must be harvested during their dormancy period in winter, foresters also have a shorter planting window than for container-grown seedlings, he said.

Container-grown seedlings are generally smaller than bare root trees, but nurseries are using larger plugs to meet foresters' demand for increased size.

"They're going away from the smaller stock types and toward the larger stock types," said John Trobough, nursery manager for the Washington Department of Natural Resources.

Smaller container-grown trees are not only more vulnerable to herbivores, but they're also less competitive with weeds, said Evelyn Hukari, a reforestation forester for the Oregon Department of Forestry.

Greenhouse conditions provide nurseries with more control over the seedling growth process, but they also pose a risk, Trobough said. "You have greater chances of making mistakes."

For example, too much fertilizer in a greenhouse system can more easily result in damage and mortality in seedlings, he said. "You don't have a lot of soil capacity here to buffer."