Learn More
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 soil water(More)
[1] Disturbances are important for renewal of North American forests. Here we summarize more than 180 site years of eddy covariance measurements of carbon dioxide flux made at forest chronosequences in North America. Net ecosystem production (NEP) showed a carbon loss from all ecosystems following a stand‐replacing disturbance, becoming a carbon sink by 20(More)
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 CO2 efflux based on CO2 gradients and diffusivity in a young ponderosa pine plantation in the Sierra Nevada(More)
At the leaf scale, it is a long-held assumption that stomata close at night in the absence of light, causing transpiration to decrease to zero. Energy balance models and evapotranspiration equations often rely on net radiation as an upper bound, and some models reduce evapotranspiration to zero at night when there is no solar radiation. Emerging research is(More)
We assessed the differential advantages of deciduousness and evergreenness by examining 26 site-years of carbon dioxide, water vapor, and energy flux measurements from five comparable oak woodlands in France, Italy, Portugal, and California (USA). On average, the evergreen and deciduous oak woodlands assimilated and respired similar amounts of carbon while(More)
The potential effects of global changes on forests are of increasing concern. Dendrochronology, which deals with long-term records of tree growth under natural environmental conditions, can be used to evaluate the impact of climatic change on forest productivity. However, assessment of climatic change impacts must be supported by accurate and reliable(More)
Like many midlatitude ecosystems, Mediterranean forests will suffer longer and more intense droughts with the ongoing climate change. The responses to drought in long-lived trees differ depending on the time scale considered, and short-term responses are currently better understood than longer term acclimation. We assessed the temporal changes in trees(More)
Global climate change is expected to result in more frequent and intense droughts in the Mediterranean region. To understand forest response to severe drought, we used a mobile rainfall shelter to examine the impact of spring and autumn rainfall exclusion on stomatal (S(L) ) and non-stomatal (NS(L) ) limitations of photosynthesis in a Quercus ilex(More)
Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating effects of positive climate–carbon cycle feedbacks. However, directly observed relationships between climate and terrestrial CO 2 exchange with the atmosphere(More)
Our first objective was to link the seasonality of fine root dynamics with soil respiration in a ponderosa pine (Pinus ponderosa P. & C. Lawson) plantation located in the Sierra Nevada of California. The second objective was to examine how canopy photosynthesis influences fine root initiation, growth and mortality in this ecosystem. We compared CO2 flux(More)