Comparison of branch biomass relationships for North Carolina and Oklahoma/Arkansas loblolly pine seed sources growing in southeastern Oklahoma

Abstract

Comparison of branch-level foliage and branch (wood+bark) biomass relationships for North Carolina Coastal (NCC) and Oklahoma/Arkansas (O/A) loblolly pine ( Pinus taeda L.) seed sources provided an indication of biomass partitioning differences between these two seed sources. The objective of this study was to quantify and compare the branch-level foliage and branch biomass of NCC and O/A provenances on an excessively drained site in southeastern Oklahoma to assess their branch-level biomass partitioning patterns; a modeling process was developed to accomplish this objective. It was found that seed source significantly influenced the amount of foliage per branch. If tree and branch dimensions were held constant, NCC branches would carry approximately 30% more foliage per branch than O/A branches. The relationship between tree and branch dimensions and branch production did not differ for the two seed sources. Vertical distributions of branch and foliage biomass were found to be similar for the two seed sources as well. Thus, on the droughty site observed in this study: (1) the NCC seed source tended to partition more biomass into the foliage component at the individual branch level than did the O/A seed source; (2) the two seed sources were similar in their propensity to partition biomass into the branch component at the branch level, and (3) the two seed sources were similar in the vertical distribution of branch and foliage biomass within the crown.