Leaf gas exchange, water potential, hyperspectral reflectance, and growth rates among saplings in loblolly pine stand

Author: Brett T. Wolfe
Collaborator: Thomas Dean
Data collectors: Joseph Kankem, Owen Nassif, Lilly Bolin, Jill Bowman, and Maruf Hossain
Affiliation: School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, Louisiana
Summary: This dataset was collected as part of an investigation into relationships among whole-plant hydraulic conductance, tree growth performance, and leaf hyperspectral reflectance. Measurements were made during the 2023 growing season (May to September) on individual trees within a loblolly pine (Pinus taeda) stand in an experimental farm in Baton Rouge, Louisiana. Data files include measurements of tree size, leaf-level gas exchange, water potential, and hyperspectral reflectance.
Repeated measurements were made on 105 Pinus taeda trees from seven different half-sib genotypes planted within a 6,500 m2 stand in Louisiana. Each tree was subjected to one of three stem-bending treatments in the mid growing season. They were either bent 45 degrees from straight 72 times, staked to prevent bending, or left as unmanipulated controls. Root-collar diameter and height were measured four times on each tree. At two time points within the growing season, leaf-level gas exchange was measured with a portable photosynthesis system (LI6400XT, LiCor Biosciences Inc.) on five leaves per tree, leaf water potential was measured at predawn and midday with a pressure chamber (PMS Instrument Company), and leaf hyperspectral reflectance was measured with a full-spectrum spectroradiometer attached to a leaf clip (HR1024i and LC-RC Pro, Spectra Vista Corporation).
The data were compiled into four comma separated vector (.csv) files, one each for plant size, gas exchange, leaf water potential, and hyperspectral reflectance. Further data processing details and the data columns of each file are described in the included README file.