Five years of carbon fluxes and inherent water-use efficiency at two semi-arid pine forests with different disturbance histories

ABSTRACT Five years of eddy-covariance and other measurements at a mature ponderosa pine forest and a nearby young plantation are used to contrast the carbon fluxes for long-term averages, seasonal patterns, diel patterns and interannual variability, and to examine the differing responses to water-stress. The mature forest with larger leaf area and wetter and cooler soils has a net uptake of carbon 3.3 times that of the young plantation. In the spring, photosynthesis is larger at the mature site as expected based on the difference in leaf area, however, another important factor is the reduction in springtime respiration at the mature site due to lower soil temperatures because of more shade from the canopy. Patterns of photosynthesis, inherent water-use efficiency (IWUE) and tree transpiration indicate that the young plantation responds to the seasonal drought sooner and to a more severe degree. Lower sensitivity to seasonal drought at the mature site is likely due to higher soil moisture reserves year round and a deeper root system that can access more water. Outside the seasonal drought period, the IWUE is the same at both sites, suggesting a species-specific value. Larger interannual variability at the plantation is associated with water-year drought and aggrading.

[1]  W. Kurz,et al.  Mountain pine beetle and forest carbon feedback to climate change , 2008, Nature.

[2]  Carbon storage and fluxes in ponderosa pine forests at different developmental stages , 2001 .

[3]  Michael G. Ryan,et al.  Seasonal and annual respiration of a ponderosa pine ecosystem , 1999 .

[4]  B. Law,et al.  Nocturnal subcanopy flow regimes and missing carbon dioxide , 2012 .

[5]  W. Oechel,et al.  Seasonality of ecosystem respiration and gross primary production as derived from FLUXNET measurements , 2001 .

[6]  T. Foken,et al.  Update of a Footprint-Based Approach for the Characterisation of Complex Measurement Sites , 2006 .

[7]  B. Law,et al.  Age-related changes in ecosystem structure and function and effects on water and carbon exchange in ponderosa pine. , 2004, Tree physiology.

[8]  F. M. Kelliherb,et al.  Spatial and temporal variation in respiration in a young ponderosa pine forest during a summer drought , 2001 .

[9]  S. Wofsy,et al.  Factors Controlling Long- and Short-Term Sequestration of Atmospheric CO2 in a Mid-latitude Forest , 2001, Science.

[10]  B. Law,et al.  Interannual variation in soil CO2 efflux and the response of root respiration to climate and canopy gas exchange in mature ponderosa pine , 2008 .

[11]  J. William Munger,et al.  Measurements of carbon sequestration by long‐term eddy covariance: methods and a critical evaluation of accuracy , 1996 .

[12]  Natascha Kljun,et al.  Carbon, energy and water fluxes at mature and disturbed forest sites, Saskatchewan, Canada , 2006 .

[13]  A. Arneth,et al.  Global patterns of land-atmosphere fluxes of carbon dioxide, latent heat, and sensible heat derived from eddy covariance, satellite, and meteorological observations , 2011 .

[14]  Christoph Thomas,et al.  Seasonal hydrology explains interannual and seasonal variation in carbon and water exchange in a semiarid mature ponderosa pine forest in central Oregon , 2009 .

[15]  Hans Peter Schmid,et al.  Biometric and eddy-covariance based estimates of annual carbon storage in five eastern North American deciduous forests , 2002 .

[16]  Beverly E. Law,et al.  Climatic versus biotic constraints on carbon and water fluxes in seasonally drought‐affected ponderosa pine ecosystems , 2004 .

[17]  A. Granier,et al.  Mesure du flux de sève brute dans le tronc du Douglas par une nouvelle méthode thermique , 1987 .

[18]  Richard H. Waring,et al.  Forest Ecosystems: Analysis at Multiple Scales , 1985 .

[19]  Richard H. Waring,et al.  Forest Ecosystem Analysis at Multiple Time and Space Scales , 2007 .

[20]  A. Goldstein,et al.  Carbon dioxide and water vapor exchange by young and old ponderosa pine ecosystems during a dry summer. , 2001, Tree physiology.

[21]  Jehn-Yih Juang,et al.  Role of vegetation in determining carbon sequestration along ecological succession in the southeastern United States , 2008 .

[22]  B. Law,et al.  Contrasting soil respiration in young and old‐growth ponderosa pine forests , 2002 .

[23]  Thermal-dissipation sap flow sensors may not yield consistent sap-flux estimates over multiple years , 2010, Trees.

[24]  T. Andrew Black,et al.  Components of ecosystem respiration and an estimate of net primary productivity of an intermediate-aged Douglas-fir stand , 2007 .

[25]  Werner A. Kurz,et al.  A 70-YEAR RETROSPECTIVE ANALYSIS OF CARBON FLUXES IN THE CANADIAN FOREST SECTOR , 1999 .

[26]  Nicholas C. Coops,et al.  Assessing the past and future distribution and productivity of ponderosa pine in the Pacific Northwest using a process model, 3-PG , 2005 .

[27]  Thomas Foken,et al.  Re-evaluation of integral turbulence characteristics and their parameterisations , 2002 .

[28]  Natascha Kljun,et al.  Climatic controls on the carbon and water balances of a boreal aspen forest, 1994–2003 , 2007 .

[29]  D. Phillips,et al.  Fine root growth and mortality in different-aged ponderosa pine stands , 2008 .

[30]  K. Hibbard,et al.  Postfire carbon pools and fluxes in semiarid ponderosa pine in Central Oregon , 2007 .

[31]  Abel Rodrigues,et al.  Net ecosystem carbon exchange in three contrasting Mediterranean ecosystems ? the effect of drought , 2007 .

[32]  Dennis D. Baldocchi,et al.  Seasonal differences in carbon and water vapor exchange in young and old-growth ponderosa pine ecosystems , 2002 .

[33]  Markus Reichstein,et al.  Temporal and among‐site variability of inherent water use efficiency at the ecosystem level , 2009 .

[34]  Scott D. Peckham,et al.  Fire as the dominant driver of central Canadian boreal forest carbon balance , 2007, Nature.

[35]  B. Law,et al.  Uncertainty estimates for 1-h averaged turbulence fluxes of carbon dioxide, latent heat and sensible heat , 2010 .

[36]  S. Wofsy,et al.  Factors controlling CO2 exchange on timescales from hourly to decadal at Harvard Forest , 2007 .

[37]  Ü. Rannik,et al.  Gap filling strategies for defensible annual sums of net ecosystem exchange , 2001 .