Better Forests From Miniature Trees

We think of forests as full of tall, soaring trees. But newly engineered dwarf trees might actually do a better job revitalizing our woodlands.

While the green revolution engineered better wheat and corn and drastically improved yields on food crops in the early 20th century, no one focused on trees. But now researchers say that engineered trees can provide more wood, better drought protection, and more greenhouse mitigation. The trick: Make them smaller.

The idea goes counter to many years of forestry research, which tried to make trees bigger. But smaller is a compelling idea, says Steven Strauss, a biologist at the University of Oregon. "We think dwarf trees will tend to use less water, and take resources from the environment more efficiently due to larger roots relative to shoots."

The way it works is this: Researchers inserted a number of genes into poplar trees, a species often used for genetic experiments, and also valuable for wood, environmental, and energy purposes. They figured out 29 genetic traits that were affected, including growth rate, biomass production, branching, water-use efficiency, and root structure. All of the changes came from modifying plant hormones that influence several aspects of growth and development. Their research was published in a recent issue of the journal Plant Physiology.

The researchers say that depending on the genes selected, they could modify trees to be almost any height. For ornamental purposes it would be possible to grow a miniature poplar, or a potted-plant-sized Douglas Fir.

But what’s more important are just shorter trees. Dwarf trees have a bigger root mass to height ratio, making them ideal for cleaning up an area after a spill, or securing soils from blowing away. And shorter, thicker, and straighter trunks might create higher-value wood products in many tree species, as well as saving on water in drought-stricken regions.

In addition, there is little fear that the genetically modified trees would take over natural populations, since their lack of height puts them at a disadvantage in natural forests.

This is a niche usage, explains Strauss—but it shows how regulations on genetic engineering could hamper efforts to improve the environment. "Stringent regulations on genetic engineering in all forms makes them essentially unusable, despite their very high inherent safety and value," said Strauss. "In my personal view, this is clearly a case of excess government regulation driven by anti-genetic engineering ideologies, not at all by science."

Trees are a vital part of ecosystems, from dry to wet. A recent study in Nature Climate Change concluded that if current climate trends continue, forests in the Southwest will go the way of the dodo—from a litany of causes, including drought and rising temperatures, but also wood-chomping pests and fires. The researchers examined forest fire data from satellites for the past 30 years in parallel with data on tree ring growth over the same period, and were able to see a strong relationship between droughts and the number of acres of forests wiped out by wildfires. Similar results have been studied in Europe. In short? Trees matter, and short ones may be able to help.

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