Elevated CO 2 does not affect stem CO 2 efflux nor stem respiration in a dry Eucalyptus woodland, but it shifts the vertical gradient in xylem [CO 2 ]

Root-derived CO(2) efflux via xylem stream rivals soil CO(2) efflux.

Respiration consumes a large portion of annual gross primary productivity in forest ecosystems and is dominated by belowground metabolism. Here, we present evidence of a previously unaccounted for internal CO(2) flux of large magnitude from tree roots through stems. If this pattern is shown to persist over time and in other forests, it suggests that belowground respiration has been grossly unde...

Wood CO(2) efflux and foliar respiration for Eucalyptus in Hawaii and Brazil.

We measured CO(2) efflux from wood for Eucalyptus in Hawaii for 7 years and compared these measurements with those on three- and four-and-a-half-year-old Eucalyptus in Brazil. In Hawaii, CO(2) efflux from wood per unit biomass declined approximately 10x from age two to age five, twice as much as the decline in tree growth. The CO(2) efflux from wood in Brazil was 8-10x lower than that for compa...

Seasonal variations in stem CO 2 efflux in the Neotropical rainforest of 1 French Guiana

Rhizosphere feedbacks in elevated CO(2).

Understanding rhizosphere processes in relation to increasing atmospheric CO(2) concentrations is important for predicting the response of forest ecosystems to environmental changes, because rhizosphere processes are intimately linked with nutrient cycling and soil organic matter decomposition, both of which feedback to tree growth and soil carbon storage. Plants grown in elevated CO(2) substan...

Stem maintenance and construction respiration in Pinus ponderosa grown in different concentrations of atmospheric CO(2).

To determine whether long-term growth in enriched CO(2) atmospheres changes the woody tissue respiration component of aboveground carbon budgets, we measured woody tissue respiration of stems of 3-year-old ponderosa pine (Pinus ponderosa Laws.) grown in ambient (350 ppm) or twice ambient (700 ppm) atmospheric CO(2) concentrations in open-top field chambers located in Placerville, CA. Total resp...