Jalmer Jokela’s research beginning in the 1970s focused on the genetics of a native poplar tree, the rapidly growing eastern cottonwood (Populus deltoides). Jokela devoted years of his career at the University of Illinois to collecting native cottonwood germplasm. The germplasm is stored as trees from a clonal nursery established on the University of Illinois South Farms and has been used by scientists throughout the world in genetics studies, hybridization programs, and in biomass field trials since the 1980s. Plantations were established at the University of Illinois by Jokela and his colleagues at both on the U of I South Farms and at the Dixon Springs Agricultural Center in the 1980s. The germplasm is stored in the form of clonal trees derived through vegetative propagation of cuttings from individual trees occurring naturally in the Mississippi River valley. His research helped to characterize the genetic variability and growth potential of eastern cottonwood populations from Louisiana to Minnesota in a regional study.
Jokela’s individual work focused on clones of eastern cottonwood ecotypes that are superior in growth rate and disease resistance from the portion of the Mississippi River valley at Illinois latitudes. Some of these select clones have been used in hybridization programs with other fast-growing poplar species such as black cottonwood from the Pacific Northwest to produce new hybrids with superior wood yields for use in biomass/biofuel plantations, for pulpwood production, and as chemical feedstock for industrial processes. These hybrids owe their superior growth characteristics to the years of genetic selection and provenance trials by Jokela. Some of these hybrids have already been used in large-scale industrial plantations along the Columbia River in the Pacific Northwest and are ideal candidates for use today as biomass producers for liquid fuel production. Jokela’s pioneering work also revealed the potential for using locally adapted, superior, native poplar germplasm as a hardy substitute for generic hybrid poplars, often derived from parent trees that occur in disparate climatic regions. Jokela’s research conducted in response to the oil crisis of the 1970s has come into its own today as the global demand for energy resources to replace fossil fuels is intensifying.