First results from a Free-Air Carbon Enrichment (FACE) facility in deciduous temperate forest
Abstract
Enhanced plant growth as a result of elevated atmospheric carbon dioxide concentrations (eCO2) is considered to be largely responsible for terrestrial ecosystems absorbing more than one quarter of anthropogenic CO2 emissions. The present-day global net land sink is located primarily in northern ecosystems, with temperate forests responsible for one-third of total uptake. Looking forward, land carbon (C) responses to eCO2 are calculated to be the most important C cycle feedback to 21st century climate change but are also the most uncertain. The newly established Birmingham Institute of Forest Research (BIFoR)-Free-Air CO2 Enrichment (FACE) facility is the first whole-ecosystem FACE experiment for decadal exposure of a mature temperate forest to elevated CO2 (eCO2). In BIFoR FACE, the trees are more than 160 years old and the forest soil is centuries older, providing a unique opportunity to fill critical gaps in the understanding of mature forest biomes. The FACE facility comprises 3 levels of treatment: ambient without infrastructure; ambient with infrastructure; and +150 ppmv above ambient eCO2) operating on two levels of canopy, each treatment being replicated 3 times. CO2 is pre-mixed with air and released from the upwind quadrant of 25-m diameter treatment patches; the release concentration and upwind direction being updated approximately every 10 s on the basis of sonic anemometer wind speeds and CO2 concentrations at the top of the canopy. The resultant 3D CO2 field within each treatment patch is monitored by 16 inlets feeding 2 infra-red gas analysers. Pre-treatment baseline measurements of ecological structure and ecophysiological function were made from 2015 to spring 2017. We present results from the first growing season under eCO2 (April -November 2017) focusing on soil respiration, fine root growth, and photosynthetic efficiency.
- Publication:
-
EGU General Assembly Conference Abstracts
- Pub Date:
- April 2018
- Bibcode:
- 2018EGUGA..2017293M