We tested the hypothesis that the date of the onset of net carbon uptake by temperate deciduous forest canopies corresponds with the time when the mean daily soil temperature equals the mean annual air temperature. The hypothesis was tested using over 30 …
Journal: International Journal Of Biometeorology, Volume 49 (6): 377-387 (2005), ISBN . DOI: 10.1007/s00484-005-0256-4 Sites: US-MMS
The transition between wintertime net carbon loss and springtime net carbon assimilation has an important role in controlling the annual rate of carbon uptake in coniferous forest ecosystems. We studied the contributions of springtime carbon assimilation …
Journal: Oecologia, Volume 146 (1): 130-147 (2005), ISBN . DOI: 10.1007/s00442-005-0169-2 Sites: US-NR1
An understanding of the effect of fertility management on soil surface fluxes of CO2, N2O, and CH4 is essential in evaluating C sequestration measures that attempt to increase the amount of crop residue returned to the soil through increased fertilizer inputs. In this study, soil surface CO2 …
Journal: Soil Science Society Of America Journal, Volume 69 (2): 387-395 (2005), ISBN . DOI: 10.2136/sssaj2005.0387 Sites: US-Ne1, US-Ne2, US-Ne3
Monoterpene fluxes have been measured over an 11 month period from June 2003 to April 2004. During all seasons ambient air temperature was the environmental factor most closely related to the measured emission rates. The monoterpene flux was modeled using a basal emission rate multiplied by an exponential function of a temperature, …
Journal: Atmospheric Chemistry And Physics Discussions, Volume 5 (5): 8791-8810 (2005), ISBN . DOI: 10.5194/acpd-5-8791-2005 Sites: US-Blo
Continuous measurements of soil respiration and its components help us understand diurnal and seasonal variations in soil respiration and its mechanism. We continuously measured CO2 concentration at various depths in the soil and calculated surface CO2efflux …
Journal: Agricultural And Forest Meteorology, Volume 132 (3-4): 212-227 (2005), ISBN . DOI: 10.1016/j.agrformet.2005.07.011 Sites: US-Blo
Increasing the abundance of fungi relative to bacteria should favor C accrual, because fungi use C more efficiently, and are composed of more recalcitrant C compounds. We examined changes in soil microbial community structure following cessation of tillage-based agriculture and through subsequent succession in a C-accruing tallgrass …
Journal: Soil Science Society Of America Journal, Volume 69 (5): 1412-1421 (2005), ISBN . DOI: 10.2136/sssaj2004.0252 Sites: US-IB1, US-IB2
Soil respiration is controlled by soil temperature, soil water, fine roots, microbial activity, and soil physical and chemical properties. Forest thinning changes soil temperature, soil water content, and root density and activity, and thus changes soil respiration. We measured soil respiration monthly and soil temperature and volumetric …
Journal: Tree Physiology, Volume 25 (1): 57-66 (2005), ISBN . DOI: 10.1093/treephys/25.1.57 Sites: US-Blo
Most satellites provide, at best, a single daily snapshot of vegetation and, at worst, these snapshots may be separated by periods of many days when the ground was obscured by cloud cover. Since vegetation carbon exchange can be very dynamic on diurnal and day-to-day timescales, the limited temporal resolution of satellite data is …
Journal: Agricultural And Forest Meteorology, Volume 131 (1-2): 1-12 (2005), ISBN . DOI: 10.1016/j.agrformet.2005.04.006 Sites: CA-Let, US-Blo, US-Ho1, US-MMS, US-NR1, US-Ton, US-Var
A better understanding of forest subcanopy flows is needed to evaluate their role in the horizontal movement of scalars, particularly in complex terrain. This paper describes detailed measurements of the canopy structure and its variability in both the horizontal …
Journal: Journal Of Applied Meteorology, Volume 44 (8): 1161-1179 (2005), ISBN . DOI: 10.1175/jam2265.1 Sites: US-Ha1
We characterized vertical variation in the seasonal release of stored soil moisture in old-growth ponderosa pine (OG-PP, xeric), and young and old-growth Douglas-fir (Y-DF, OG-DF, mesic) forests to evaluate changes in water availability for root uptake. Soil water potential (ψ) and volumetric water content (θ) …
Journal: Agricultural And Forest Meteorology, Volume 130 (1-2): 39-58 (2005), ISBN . DOI: 10.1016/j.agrformet.2005.01.004 Sites: US-Me4