Complementarity increases production in genetic mixture of loblolly pine ( Pinus taeda L.) throughout planted range

Abstract

Increased genotypic diversity has been associated with increased biomass production in shortrotationtree species. Increasing the genotypic diversity of loblolly pine (Pinus taeda L.) in an attempt toincrease productivity has not been extensively studied nor tested operationally or over long durations (i.e.,>7 yr). We used genetically mixed and pure rows of loblolly pine growing throughout its planted range—Virginia, North Carolina, and Brazil—to test the effects of genetic mixing on volume production. Therewere no significant effects of mixing rows compared to pure rows on uniformity or mortality. Under intensivesilviculture, individual trees planted in mixed rows had approximately 7% greater volume than thosein the pure rows (estimate = 0.015 m³/tree ± 0.006) in the final year of measurement—year 8 for Braziland year 10 for North Carolina and Virginia. Scaling the increase in individual stem volume under mixedrows and intensive silviculture to 1235 stems ha⁻¹ would equate to an additional 1.85 m³ha⁻¹yr⁻¹ inmean annual increment. Measuring the net biodiversity effect, our data suggest the positive growthresponse is driven by complementarity and not selection, meaning both genetic entries tend to grow largerwhen grown together. Additional trials are necessary to test the effects of mixing rows across large plotsand to assess whether this increase is sustained throughout the rotation. If this increasing trend were tohold for intensively managed plantations, strategically mixing rows to increase productivity could be avaluable addition to an intensively managed plantation requiring relatively little added operational considerationto implement.

Citation

Carter, David R.; Albaugh, Timothy J.; Campoe, OtÁvio C.; Grossman, Jake J.; Rubilar, Rafael A.; Sumnall, Matthew; Maier, Christopher A.; Cook, Rachel L.; Fox, Thomas R. 2020. Complementarity increases production in genetic mixture of loblolly pine ( Pinus taeda L.) throughout planted range . Ecosphere. 11(11): 337-. https://doi.org/10.1002/ecs2.3279.