At Bradshaw, thousands of black cottonwoods were planted in a 3-acre plot in May. Among them are three clones, each of 1,000 genetically different trees, created by transplanting cuttings from the same tree. More sapling clones of the 1,000 individuals are planted in three other gardens in Oregon.

Lead researcher Jerry Tuskan of the Oak Ridge National Laboratory said his team has mapped the genome of each tree and will compare how the various clones survive in different climates. Already, some are doing better than others, with some trees reaching about five feet in height and others barely reaching more than a few inches.

Over the course of the experiment, the researchers will identify the trees that do better under the hotter, drier conditions like those at Bradshaw Ranch and then see if the presence or absence of a specific set of genes can be linked to a plant’s performance in that climate, Tuskan said.

“If we want to maintain a riparian ecosystem in the desert Southwest, some trees under drought may die and other trees may survive,” Tuskan said. “If we know trees likely to survive, we can collect seeds and repopulate ecosystems with drought tolerant individuals.”