Competition dynamics in pure- versus mixed-family stands of loblolly and slash pine in the southeastern United States
2009
Staudhammer, Christina L. | Jokela, Eric J. | Martin, Timothy A.
Few studies within the native range of loblolly (Pinus taeda L.) and slash pine (Pinus elliottii Engelm. var. elliottii) have compared yield and stand dynamics in pure-family block versus mixed-family block plantings under a range of silvicultural treatments. Understanding intergenotypic competitive interactions is important for predicting phenotypic performance, defining growth strategies and ideotypes, and deploying the correct mix of families that possess complementary characteristics for enhanced yield and pest resistance. In 2000, replicated experimental trials were installed in the southeastern United States, controlling for genotype (pure- and mixed-family plantings; consisting of seven full-sibling loblolly and six full-sibling slash pine families), planting density (1334 vs. 2990 trees/ha), and levels of silvicultural treatment intensity (operational vs. intensive). We measured four installations of these trials. There were numerous examples of differential family performance in mixed versus pure plots manifested as significant deployment x family interactions for diameter at breast height, height, basal area, volume, survival, disease, and damage traits. Significant and consistent interactions of several families with mixed versus pure deployment led to the identification of putative crop and competition ideotypes in both loblolly and slash pine. Tree-level crown architectural traits and an index of growth efficiency for the identified families were consistent with the hypothesized ideotypes.
显示更多 [+] 显示较少 [-]