Survival and growth of a range of Populus clones in central South Carolina USA through age ten: Do early assessments reflect longer-term survival and growth trends?

Increased emphasis is being placed on developing bioenergy production capacity in the United States and Populus species or hybrids have been identified as strong candidates for the southeastern United States. Thirty-one Populus clones were planted in South Carolina and survival and growth assessments were completed after the 1st, 2nd, 3rd, and 10th growing seasons. Survival and growth differed significantly among clones. Age-to-age correlations for survival and growth traits were made and results suggest that for most clones, age 10 survival was strongly correlated with first-year survival. A small group of clones exhibited delayed mortality indicating poor longer-term adaptability. For growth, clonal selections based on age 3 volumes could be made and rank changes involve moderate to poorly performing clones. Clones with the greatest age 3 volumes, 184-411, WV416, and 52-225, ranked 1st, 2nd, and 3rd for age 10 volume. These clones represent both T × D hybrids and pure Populus deltoides clones suggesting growth is a function of specific clonal characteristics rather than overall species or hybrid traits. The growth obtained under these test conditions is generally less than the maximum growth rates of the same clones obtained in various tests. Potential reasons for this variation are discussed. To develop Populus as a commercially viable bioenergy crop for the southeastern United States, concurrent research to identify site requirements, adaptability, and appropriate management regimes is needed. Further breeding and clonal selection will be critically important, but it is unlikely that this alone will be sufficient to assure high productivity.

► Thirty-one Populus clones were assessed over ten years.
► Tree survival and growth differed significantly among clones at all ages.
► For growth, selections at age 3 accurately reflect growth at age 10.
► Clones with the greatest age three volumes, ranked number 1st, 2nd, and 3rd at age 10.
► Identification of site requirements, adaptability, and management regimes is needed.