title: Pinus taeda forest growth predictions in the 21st century vary with site mean annual temperature and site quality.
abstract: Climate projections from 20 downscaled global climate models (GCMs) were used with the 3-PG model to predict the future productivity and water use of planted loblolly pine (Pinus taeda) growing across the southeastern United States. Predictions were made using Representative Concentration Pathways (RCP) 4.5 and 8.5. These represent scenarios in which total radiative forcing stabilizes before 2100 (RCP 4.5) or continues increasing throughout the century (RCP 8.5). Thirty-six sites evenly distributed across the native range of the species were used in the analysis. These sites represent a range in current mean annual temperature (14.9-21.6°C) and precipitation (1,120-1,680 mm/year). The site index of each site, which is a measure of growth potential, was varied to represent different levels of management. The 3-PG model predicted that aboveground biomass growth and net primary productivity will increase by 10%-40% in many parts of the region in the future. At cooler sites, the relative growth increase was greater than at warmer sites. By running the model with the baseline [CO2] or the anticipated elevated [CO2], the effect of CO2on growth was separated from that of other climate factors. The growth increase at warmer sites was due almost entirely to elevated [CO2]. The growth increase at cooler sites was due to a combination of elevated [CO2] and increased air temperature. Low site index stands had a greater relative increase in growth under the climate change scenarios than those with a high site index. Water use increased in proportion to increases in leaf area and productivity but precipitation was still adequate, based on the downscaled GCM climate projections. We conclude that an increase in productivity can be expected for a large majority of the planted loblolly pine stands in the southeastern United States during this century.
authors.affiliation: Department of Forest Engineering, Resources and Management, College of Forestry, Oregon State University, Corvallis, OR, USA.
authors.forename: Carlos A
authors.identifier: 0000-0002-6359-6214
authors.initials: CA
authors.lastname: Gonzalez-Benecke
authors.affiliation: School of Forestry and Natural Resources, University of Georgia, Athens, GA, USA.
authors.forename: Robert O
authors.initials: RO
authors.lastname: Teskey
authors.affiliation: State Climate Office of North Carolina, Raleigh, NC, USA.
authors.forename: Heather
authors.initials: H
authors.lastname: Dinon-Aldridge
authors.affiliation: School of Forest Resources and Conservation, University of Florida, Gainesville, FL, USA.
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Martin
mesh_terms: D018533:Biomass; D057231:Climate Change; D065928:Forests; D041603:Pinus taeda / Q000254:growth & development*; D018515:Plant Leaves; D015144:Southeastern United States; D013696:Temperature; D014867:Water
chemical_list: D014867:Water
keywords: aboveground biomass; forest productivity; global climate model; leaf area index; loblolly pine; net primary productivity; process model; representative concentration pathway; transpiration