title: Spatial variability of organic layer thickness and carbon stocks in mature boreal forest stands--implications and suggestions for sampling designs.
abstract: Accurate field measurements from inventories across fine spatial scales are critical to improve sampling designs and to increase the precision of forest C cycling modeling. By studying soils undisturbed from active forest management, this paper gives a unique insight in the naturally occurring variability of organic layer C and provides valuable references against which subsequent and future sampling schemes can be evaluated. We found that the organic layer C stocks displayed great short-range variability with spatial autocorrelation distances ranging from 0.86 up to 2.85 m. When spatial autocorrelations are known, we show that a minimum of 20 inventory samples separated by ∼5 m is needed to determine the organic layer C stock with a precision of ±0.5 kg C m(-2). Our data also demonstrates a strong relationship between the organic layer C stock and horizon thickness (R (2) ranging from 0.58 to 0.82). This relationship suggests that relatively inexpensive measurements of horizon thickness can supplement soil C sampling, by reducing the number of soil samples collected, or to enhance the spatial resolution of organic layer C mapping.
authors.affiliation: Department of Forest Resources, University of Minnesota, 115 Green Hall, 1530 Cleveland Ave. N., St. Paul, MN, 55108, USA, terjekrist@gmail.com.
authors.forename: Terje
authors.initials: T
authors.lastname: Kristensen
authors.forename: Mikael
authors.initials: M
authors.lastname: Ohlson
authors.forename: Paul
authors.initials: P
authors.lastname: Bolstad
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Nagy
mesh_terms: D002244:Carbon / Q000032:analysis; D057486:Carbon Cycle; D004463:Ecology / Q000379:methods; D065928:Forests; D009930:Organic Chemicals / Q000032:analysis*; D012987:Soil; D066188:Taiga; D014197:Trees
chemical_list: D009930:Organic Chemicals; D012987:Soil; D002244:Carbon