Tools for better prediction of deep soil carbon accumulation in North American forests based on FIA data
Abstract
Forest ecosystems are currently considered net carbon (C) sinks. The strength of these C sinks in a warming climate, however, will likely depend on how C stored in deep soil responds to climate changes. This presents a challenge because not only are the mechanisms pertaining to soil C stability still uncertain, but there is still a paucity of data on deep soil C contents in forest ecosystems. The goal of this study is to develop predictive equations that rely on readily available information (US Forest Service Forest Inventory Analysis data) concerning forest stands. To do so we sampled 217 forest sites in Minnesota at depths to 150cm to investigate to what extent deep soil C content can be explained by the amount of C that accumulates in the top 20cm of the mineral soil and other available data. Preliminary analyses show that C concentration in the top 20cm can predict between 16% to 46% of the C stored in deep soil, depending on forest type. Stronger relationships were associated with conifer stands, and weaker relationships were associated with hardwood stands. Mixed forests showed a relationship similar to conifers, with 45% of C accumulation in deep soil being predicted by top C%. Predictive power of top C% decreases with increasing depth, but it is stronger (between 28% and 41%) up to 100cm depth for conifers than for hardwoods, with no significant effect of texture (sand versus finer textures). Large variability was observed for hardwood stands, where only 8 to 10% of C of deep soil C (up to 100cm) was predicted by top C% in presence of sand texture and between 10% and 23% in finer-texture sites. Further analyses are needed to determine additional variables that affect C accumulation at depth.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.B23A0435F
- Keywords:
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- 0428 BIOGEOSCIENCES / Carbon cycling;
- 0486 BIOGEOSCIENCES / Soils/pedology