skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: THE RESILIENCE OF UPLAND-OAK FOREST CANOPY TREES TO CHRONIC AND ACUTE PRECIPITATION MANIPULATIONS

Abstract

Implications of chronic ( 33 percent) and acute (-100 percent) precipitation change were evaluated for trees of upland-oak forests of the eastern United States. Chronic manipulations have been conducted since 1993, and acute manipulations of dominant canopy trees (Quercus prinus; Liriodendron tulipifera) were initiated in 2003. Through 12 years of chronic manipulations tree growth remained unaffected by natural or induced rainfall deficits even though severe drought conditions dramatically reduced canopy function in some years. The resilience of canopy trees to chronic-change was the result of a disconnect between tree growth phenology and late-season drought occurrence. Acute precipitation exclusion from the largest canopy trees also produced limited growth reductions from 2003 through 2005. Elimination of lateral root water sources for the acute treatment trees, via trenching midway through the 2004 growing-season, forced the conclusion that deep rooting was a key mechanism for large-tree resilience to severe drought.

Authors:
 [1];  [1];  [1];  [1];  [2]
  1. ORNL
  2. University of Tennessee, Knoxville (UTK)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Oak Ridge National Environmental Research Park
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
930814
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: 15th Central Hardwood Forest Conference, Knoxville, TN, USA, 20060227, 20060301
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; DROUGHTS; FORESTS; OAKS; PHENOLOGY; ATMOSPHERIC PRECIPITATIONS; PLANT GROWTH; ROOTS; DEPTH

Citation Formats

Hanson, Paul J, Tschaplinski, Timothy J, Wullschleger, Stan D, Todd Jr, Donald E, and Auge, Robert M. THE RESILIENCE OF UPLAND-OAK FOREST CANOPY TREES TO CHRONIC AND ACUTE PRECIPITATION MANIPULATIONS. United States: N. p., 2007. Web.
Hanson, Paul J, Tschaplinski, Timothy J, Wullschleger, Stan D, Todd Jr, Donald E, & Auge, Robert M. THE RESILIENCE OF UPLAND-OAK FOREST CANOPY TREES TO CHRONIC AND ACUTE PRECIPITATION MANIPULATIONS. United States.
Hanson, Paul J, Tschaplinski, Timothy J, Wullschleger, Stan D, Todd Jr, Donald E, and Auge, Robert M. Mon . "THE RESILIENCE OF UPLAND-OAK FOREST CANOPY TREES TO CHRONIC AND ACUTE PRECIPITATION MANIPULATIONS". United States. doi:.
@article{osti_930814,
title = {THE RESILIENCE OF UPLAND-OAK FOREST CANOPY TREES TO CHRONIC AND ACUTE PRECIPITATION MANIPULATIONS},
author = {Hanson, Paul J and Tschaplinski, Timothy J and Wullschleger, Stan D and Todd Jr, Donald E and Auge, Robert M.},
abstractNote = {Implications of chronic ( 33 percent) and acute (-100 percent) precipitation change were evaluated for trees of upland-oak forests of the eastern United States. Chronic manipulations have been conducted since 1993, and acute manipulations of dominant canopy trees (Quercus prinus; Liriodendron tulipifera) were initiated in 2003. Through 12 years of chronic manipulations tree growth remained unaffected by natural or induced rainfall deficits even though severe drought conditions dramatically reduced canopy function in some years. The resilience of canopy trees to chronic-change was the result of a disconnect between tree growth phenology and late-season drought occurrence. Acute precipitation exclusion from the largest canopy trees also produced limited growth reductions from 2003 through 2005. Elimination of lateral root water sources for the acute treatment trees, via trenching midway through the 2004 growing-season, forced the conclusion that deep rooting was a key mechanism for large-tree resilience to severe drought.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • A throughfall displacement system was established in an upland oak forest stand on Walker Branch Watershed in the fall of 1993. Three 80[times]80 m plots were established adjacent to each other. The system is designed to displace 33% of the throughfall from one plot to another with one ambient plot. Pretreatment and first year post-treatment bole respiration rates were determined at intervals throughout the 1993 and 1994 growing seasons on mature Acer rubrum L., Quercus alba L, and Quercus prinus L. Maintenance and growth respiration data will be presented. Preliminary analysis of the pretreatment data, expressed as CO[sub 2] evolvedmore » per unit of cambial surface area, showed positive correlations between tree diameter, sapwood volume, and respiration rates during the [open quotes]dormant[close quotes] season. However, these correlations did not appear during diameter growth, indicating that cambial activity may be the major source of CO[sub 2] efflux from the bole surface during the growing season.« less
  • Observed responses of upland-oak vegetation of the eastern deciduous hardwood forest to changing CO2, temperature, precipitation and tropospheric ozone (O3) were derived from field studies and interpreted with a stand-level model for an 11-year range of environmental variation upon which scenarios of future environmental change were imposed. Scenarios for the year 2100 included elevated [CO2] and [O3] (1385ppm and 120 ppb, respectively), warming (14 1C), and increased winter precipitation (120% November-March). Simulations were run with and without adjustments for experimentally observed physiological and biomass adjustments. Initial simplistic model runs for single-factor changes in CO2 and temperature predicted substantial increases (1191%more » or 508 gCm 2 yr 1) or decreases ( 206% or 549 gCm 2 yr 1), respectively, in mean annual net ecosystem carbon exchange (NEEa 266 23 gCm 2 yr 1 from 1993 to 2003). Conversely, single-factor changes in precipitation or O3 had comparatively small effects on NEEa (0% and 35%, respectively). The combined influence of all four environmental changes yielded a 29% reduction in mean annual NEEa. These results suggested that future CO2-induced enhancements of gross photosynthesis would be largely offset by temperature-induced increases in respiration, exacerbation of water deficits, and O3-induced reductions in photosynthesis. However, when experimentally observed physiological adjustments were included in the simulations (e.g. acclimation of leaf respiration to warming), the combined influence of the year 2100 scenario resulted in a 20% increase in NEEa not a decrease. Consistent with the annual model's predictions, simulations with a forest succession model run for gradually changing conditions from 2000 to 2100 indicated an 11% increase in stand wood biomass in the future compared with current conditions. These model-based analyses identify critical areas of uncertainty for multivariate predictions of future ecosystem response, and underscore the importance of long term field experiments for the evaluation of acclimation and growth under complex environmental scenarios.« less
  • Crown light environments of juvenile trees were assessed using photographic techniques in primary tropical wet forest at La Selva Biological Station, Cost Rica. Hemispherical (fisheye) photographs were taken of the canopy above saplings of the emergent trees Lecythis ampla and Dipteryx panamensis and the subcanopy palms Welfia georgii and Iriartea gigantea. Negatives were video digitized and computer analyzed to estimate direct and diffuse components of light entering through openings in the canopy. Results from analyses of canopy photographs were calibrated using results of quantum sensor studies. Growth rates were directly related to inferred light availability. Changes in growth rates frommore » year to year were associated with changes in canopy openings. Asymmetry of canopy openings resulted in substantial intracrown variability in quantum sensor measurements.« less
  • The interest in the development and improvement of the dynamic global vegetation models (DGVMs), which have the potential to simulate fluxes of carbon, water and nitrogen, and vegetation dynamics in an integrated system has been increasing. In this paper, some numerical schemes and a higher resolution soil texture dataset are employed to improve the Sheffield Dynamic Global Vegetation Model (SDGVM). Using the eddy covariance-based measurements, we then test the standard version of the SDGVM and the modified version of the SDGVM. Detailed observations of daily carbon and water fluxes made at the upland oak forest on the Walker Branch Watershedmore » in Tennessee, USA offered a unique opportunity for these comparisons. The results revealed that, the modified version of the SDGVM did a reasonable job of simulating the carbon flux, water flux and the variation of soil water content. However, at the end of the growing season, it failed to simulate the dynamics of limitations on the soil respiration and as a result underestimated the soil respiration. It was also noted that the modified version overestimated the increase in soil water content following summer rainfall, which was attributed to an inadequate representation of the ground water and thermal cycle.« less
  • Whole-tree harvesting increased the export of biomass N, P, K, and Ca by 2.6, 2.9, 3.1, 3.3, and 2.6 times, respectively, compared to sawlog harvesting in an upland mixed oak forest in eastern Tennessee. Whole-tree harvesting after leaf fall reduced the potential drains of N, P, K, and Ca by 7, 7, 23, and 5% respectively, compared with potential removal by harvesting during the growing season. Due to low soil Ca content and high Ca content in woody tissues, whole-tree harvesting depleted total ecosystem Ca to a much greater extent than N, P, or K. Soil reserves and atmospheric inputsmore » may be adequate to sustain total N, P, and K supplies with whole-tree harvesting, but soil amendments may be necessary to sustain Ca supplies.« less