Models in country scale carbon accounting of forest soils

Abstract

Countries need to assess changes in the carbon stocks of forest soils as a part of national greenhouse gas (GHG) inventories under the United Nations Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol (KP). Since measuring these changes is expensive, it is likely that many countries will use alternative methods to prepare these estimates. We reviewed seven well-known soil carbon models from the point of view of preparing country-scale soil C change estimates. We first introduced the models and explained how they incorporated the most important input variables. Second, we evaluated their applicability at regional scale considering commonly available data sources. Third, we compiled references to data that exist for evaluation of model performance in forest soils. A range of process-based soil carbon models differing in input data requirements exist, allowing some flexibility to forest soil C accounting. Simple models may be the only reasonable option to estimate soil C changes if available resources are limited. More complex models may be used as integral parts of sophisticated inventories assimilating several data sources. Currently, measurement data for model evaluation are common for agricultural soils, but less data have been collected in forest soils. Definitions of model and measured soil pools often differ, ancillary model inputs require scaling of data, and soil C measurements are uncertain. These issues complicate the preparation of model estimates and their evaluation with empirical data, at large scale. Assessment of uncertainties that accounts for the effect of model choice is important part of inventories estimating large-scale soil C changes. Joint development of models and large-scale soil measurement campaigns could reduce the inconsistencies between models and empirical data, and eventually also the uncertainties of model predictions.

Soil carbon stock increases in the organic layer of boreal middle-aged stands

“…Currently, the majority of the countries that are able to report soil carbon apply model based approaches and only a few countries can rely on repeated soil measurements. In general, soil carbon models that can also be used in the GHG reporting (Peltoniemi et al, 2007) predict loss of carbon in regenerated young stands and accumulation of soil carbon in the middle-aged stands (Mäkipää et al, 1999;Peltoniemi et al, 2004;Palosuo et al, 2008). Such a modeled pattern is in good agreement with the chronosequence studies (e.g.…”

Biodiversity, carbon storage and dynamics of old northern forests

“…Spatial variability may be high, while changes in soil organic matter stocks in boreal forests are usually small compared with existing stocks (Häkkinen et al 2011). Therefore, models are developed with an aim to quantify soil carbon sequestration and many of them are applicable for nation-wide soil carbon assessment (Peltoniemi et al 2007). …”

Dynamics of soil organic carbon stock in a typical catchment of the Loess Plateau: comparison of model simulations with measurements

“…Peng et al 2002;Karhu et al 2011;Palosuo et al 2012). However, there are several kinds of dynamic soil C models available varying in terms of model complexity and requirements of input information (Liski et al 2005;Peltoniemi et al 2007). Some of these models are process-oriented and characterize soil C dynamics at a relatively detailed level, and therefore require detailed input information.…”