Category Archives: Special Topics

Assisted Migration

What It Means to Nursery Managers and Tree Planters

Mary I. Williams and R. Kasten Dumroese Postdoctoral Research Associate, Michigan Technological University, Houghton, MI, stationed at the U.S. Department of Agriculture (USDA) Forest Service, Rocky Mountain Research Station, Moscow, ID; Research Plant Physiologist, USDA Forest Service, Rocky Mountain Research Station, Moscow, ID


Projections indicate that natural plant adaptation and migration may not keep pace with climate changes. This mismatch in rates will pose significant challenges for practitioners that select, grow, and outplant native tree species. Populations of native tree species planted today must be able to meet the climatic challenges they will face during this century. One strategy to meet this challenge is assisted migration, the intentional movement of plant materials in response to climate change to maximize survival and curtail maladaptation. For successful assisted migration, climate changes will need to be met by changes in ethical, legal, political, and economical paradigms, as well as with the way foresters view seed transfer guidelines. We review and explore assisted migration as an adaptation strategy, discuss the role of nurseries, present some working examples, and provide tools and resources for consultation. Continue reading


By Richard Haard, Propagator, Fourth Corner Nurseries

From Merriam-Webster… Anthropogenic : of, relating to, or resulting from the influence of human beings on nature

Here in the lower 48 states it is difficult to find a tract that has not been influenced by the hand of man or by livestock. Plant communities containing natural vegetation are either obliterated or contaminated with escaped ornamentals or by the seeds of weeds and exotic grasses borne by hay fed animals, farming activities and passing cars.

In some places though, as in the high forest country or the remote north of Alaska, where wilderness surrounds civilization, these exotics are absent and we can see the countryside with its natural endowment. Occasionally we come across modifications to the natural landscape we inherited from our original peoples, who have lived here for as long as 12,000 years, which adds an interesting angle to these thoughts. Continue reading

Sex and the Single Salix

by Thomas Landis, David Dreesen & R. Kasten Dumroese

This article, reprinted with the authors’ permission, was originally printed in Native Plants Journal, Volume 4, Number 2 (Fall 2003), and can be viewed with more graphics at


Most restoration projects strive to create a sustainable plant community but exclusive use of vegetatively propagated material may be preventing this goal. The dioecious willows and cottonwoods of the Salicaceae are widely used in riparian restoration projects. Hardwood cuttings have traditionally been used to propagate these species in nurseries, and live stakes, branched cuttings, and poles are also used in bioengineering structures for bank stabilization. Woody cuttings are collected either from the project site or from stooling beds in nurseries during the winter dormant period. Unfortunately, little attention has been given to the sex of the donor plants. The potential problem is that a proper mixture of male and female plants may not be present in the hardwood cuttings or rooted cuttings destined for the restoration site—in the worst case they may be entirely 1 sex or the other. Fortunately, it is relatively easy to distinguish male and female plants. Continue reading

Wetland Restoration, Creation & Enhancement in the Northwest

by Sarah Spear Cooke, Ph.D. – Cooke Scientific Services, Seattle, WA

Wetlands are elaborate ecosystems which perform many functions in the landscape. A few of the better known functions are stormwater storage, erosion prevention, sediment and pollutant filtration, and the presence of plant communities which provide habitat for wildlife. Even the most diverse team of experts cannot identify all the functional constituents of a wetland because processes within wetlands interact in complex ways. How then do we create, restore, or enhance these systems without thoroughly understanding them? This is a question many managers and ecologists have asked in light of the poor success that has been achieved to date with these types of projects. Continue reading

The Use of Aquatic Plants to Treat Waste Water

by Cristian Frers, Senior Environmental Manager and Consultant; Translated by Veronica Wisniewski

We are publishing this article in this edition as an exploration of the alternative treatment methods being employed in other countries around the world. Cristian Frers is a Senior Environmental Manager and Consultant in Argentina where the techniques discussed below are being employed to treat industrial waste water. Thanks to Ecoportal ( and Mr. Frers for allowing us to translate and reprint this article.

benefits of constructed wetlands as wastewater treatment systems

Because they require little or no energy to function, constructed wetlands offer distinct advantages over alternative treatment systems. If there is adequate inexpensive land suitable for aquatic conditions and available for the installation of artificial wetlands, such an approach to wastewater treatment can be a cost effective alternative. As an added advantage, such wetlands provide habitat for wildlife.


The importance of wetlands has changed over time. Wetlands serve as transition zones between aquatic and terrestrial environments and provide a dynamic link between the two. Moving along a gradient, water picks up chemicals and sediments which, as they move through the wetland, are transformed and transported to the surrounding landscape.

Wetlands are effective nutrient sinks and absorbers of organic and inorganic pollutants. This absorptive capacity of a natural wetland is the mechanism employed in a constructed wetland for the purpose of treating wastewater from businesses and municipalities. Continue reading