Soil total and charcoal carbon from mountain shrublands to subalpine forests in the Colorado Front Range
Abstract
Temperate conifer forests and mountain shrublands in the Rocky Mountain Front Range, Colorado are fire-adapted ecosystems where wildland fires leave a legacy in the form of char and charcoal. Long-term, persistent soil charcoal carbon pools result from the combined effects of repeated wildland fires, aboveground biomass characteristics and soil transfer mechanisms. However, only a few studies have measured these pools in the dominant vegetation types of this region at a watershed scale. We quantified charcoal C in the upper 10 cm mineral soil with a thermochemical digest method which retains only the most recalcitrant C forms for mid-slope positions with east facing aspects and discovered that charcoal C pools do not follow a linear pattern of increasing amounts with elevation gain. A significant statistical effect of vegetation type on soil charcoal C pools along this ecological gradient suggests fire-derived charcoal C forms and accumulates via unique conditions such as fire regime. There is a bimodal pattern of initial charcoal C gain with elevation between mountain shrublands and the lower montane forest types prior to a mid-elevation decline in upper montane lodgepole pine forests before increasing again in the subalpine forests. Charcoal C amounts did not cause a significant increase or decrease in total SOC pools in these vegetation types in contrast with findings for other temperate ecosystems. Both the range of total soil charcoal C and ratios of charcoal C to total SOC are comparable to but lower than other regional estimates. This study yielded one of the largest collections of soil samples analyzed for charcoal C in the United States. Future modeling and field-based efforts are called for after revealing a landscape-pattern of SOC and charcoal C pools across these vegetation types.
- Publication:
-
EGU General Assembly Conference Abstracts
- Pub Date:
- April 2012
- Bibcode:
- 2012EGUGA..1413741L