Litter mass loss rates in pine forests of Europe and Eastern United States: some relationships with climate and litter quality

Abstract

Abstract. The purpose of this study was to relate regional variation in litter mass-loss rates (first year) in pine forests to climate across a large, continental-scale area. The variation in mass-loss rate was analyzed using 39 experimental sites spanning climatic regions from the subarctic to subtropical and Mediterranean: the latitudinal gradient ranged from 31 N to 70 N and may represent the the largest geographical area that has ever been sampled and observed for the purpose of studying biogeochemical processes. Because of unified site design and uniform laboratory procedures, data from all sites were directly comparable and permitted a determination of the relative influence of climate versus substrate quality viewed from the perspective of broad regional scales.Simple correlation applied to the entire data set indicated that annual actual evapotranspiration (AET) should be the leading climatic constraint on mass-loss rates (R2d = 128 0.496). The combination of AET, average July temp. and average annual temp. could explain about 70% of the sites' variability on litter mass-loss. In an analysis of 23 Scots pine sites north of the Alps and Carpatians AET alone could account for about 65% of the variation and the addition of a substrate-quality variable was sufficiently significant to be used in a model.The influence of litter quality was introduced into a model, using data from 11 sites at which litter of different quality had been incubated. These sites are found in Germany, the Netherlands, Sweden and Finland. At any one site most (> 90%/6) of the variation in mass-loss rates could be explained by one of the litter-quality variables giving concentration of nitrogen, phosphorus or water solubles. However, even when these models included nitrogen or phosphorus even small changes in potential evapotranspiration resulted in large changes in early-phase decay rates.Further regional subdivision of the data set, resulted in a range of strength in the relationship between loss rate and climatic variables, from very weak in Central Europe to strong for the Scandinavian and Atlantic coast sites (Rdj = 0.912; AET versus litter mass loss). Much of the variation in observed loss rates could be related to continental versus marine/Atlantic influences. Inland locations had mass-loss rates lower than should be expected on the basis of for example AET alone. Attempts to include seasonality variables were not successful. It is clear that either unknown errors and biases, or, unknown variables are causing these regional differences in response to climatic variables. Nevertheless these results show the powerful influence of climate as a control of the broad-scale geography of mass-loss rates and substrate quality at the stand level.Some of these relationships between mass-loss rate and climatic variables are among the highest ever reported, probably because of the care taken to select uniform sites and experimental methods. This suggest that superior, base line maps of predicted mass-loss rates could be produced using climatic...

Clay content drives carbon stocks in soils under a plantation of Eucalyptus saligna Labill. in southern Brazil

“…The leaf litter decomposition rate was determined by the litter-bag method (Berg et al 1993). In May 2009, recently fallen senescent leaves were collected, dried at 60°C, weighed and placed into 25 × 25 cm nylon litter bags.…”

Scots pine litter decomposition along drainage succession and soil nutrient gradients in peatland forests, and the effects of inter-annual weather variation

“…Litter decomposition has been widely studied in mineral soil sites and under controlled laboratory conditions. Most of the variation in decomposition rates can be explained by litter quality, temperature and soil moisture (Berg et al, 1993;Walse et al, 1998). In pristine (undrained) peatlands, decomposition of similar litter materials is related not only to water level (e.g., Santelmann, 1992) but also to soil and/or soil water pH and base cation content (Verhoeven and Toth, 1995;Verhoeven et al, 1996;Szumigalski and Bayley, 1996) being generally faster in fens than bogs (Farrish and Grigal, 1988;Verhoeven et al, 1990).…”

Climate and litter quality controls on decomposition: An analysis of modeling approaches

“…Recently, studies have begun to address decomposition processes in a broader context of site, climate, and litter quality interactions, including the Long-Term Intersite Decomposition Experiment Team (LIDET) [LIDET, 1995] in the United States, Decomposition Study (DECO) [Berg et al, 1993] in Europe, and Canadian Intersite Decomposition Experiment Team (CIDET) [Tro•mow et al, 1995] in Canada. In these experiments, litter types spanning a range of initial quality characteristics have been placed in ecosystems that differ in cli-575 matic and edaphic features.…”