Genetically modified poplars in contextl

by Steven H. Strauss, Stephen P. DiFazio and Richard Meilan Poplars (genus Populus) have emerged as a model organism for forest biotechnology, and genetic modification (GM: asexual gene transfer) is more advanced for this genus than for any other tree. The goal of this paper is to consider the benefits expected from the use of GM poplar trees, and the most significant claims made for environmental harm, by comparing them to impacts and uncertainties that are generally accepted as part of intensive tree culture. We focus on the four traits with greatest commercialization potential in the near term: wood modification, herbicide tolerance, insect resistance, and flowering control. After field trials and selection of the top performing trees, similar to that during conventional poplar breeding, GM poplars appear vigorous and express their new traits reliably. The ecological issues expected from use of GM poplars appear similar in scope to those managed routinely during conventional plantation culture, which includes the use of exotic and hybrid genotypes, short rotations, intensive weed control, fertilization, and density control. The single-gene traits under consideration for commercial use are unlikely to cause a significant expansion in ecological niche, and thus to substantially alter poplar's ability to "invade" wild populations. We conclude that the ecological risks posed by GM poplars are similar in magnitude, though not in detail, to those of routine poplar culture. We also argue that the tangible economic and environmental benefits of GM poplars for some uses warrant their near-term adoption-if coupled with adaptive research and monitoring-so that their economic and ecological benefits, and safety, can be studied on commercially and ecologically relevant scales. We believe that the growing demand for both wood products and ecological services of forests justifies vigorous efforts to increase wood production on land socially zoned for tree agriculture, plantations, or horticulture. This is the key reason for poplar biotechnology: the combination of economic efficiency with reduction of farm and forestry impact on the landscape.