Volume No. 4 Issue No.: 2 Page No.: 321-333 Oct.-Dec 2009

 

FEATURES OF COARSE WOODY DEBRIS DECOMPOSITION IN FOREST ECOSYSTEMS OF DIFFERENT NATURAL ZONES OF CENTRAL SIBERIA

 

L.V. Mukhortova* and O.V. Trefilova

V.N. Sukachev Institute of Forest, Russian Academy of Sciences,
Siberian Branch, Krasnoyarsk (RUSSIA)

 

Received on : July 05, 2009

 

ABSTRACT

 

Coarse woody debris (CWD) is an integral component of forest ecosystems and it serve as a long-term storage of carbon and nutrients. We have investigated changes in carbon, nutrients and organic matter of differently decomposed CWD samples from forest-tundra, northern, middle and southern taiga of Central Siberia in order to assess the role of CWD in carbon and nutrient cycling in these forest ecosystems. Samples included live wood, boles at I, II and III stages of decomposition and fragments of decomposed wood from forest litter that were collected in larch, spruce, pine and fir forests.
As result of our study it was found that initially living wood of trees at northern ecosystems contains larger amount of N, P, Ca and K. Carbon concentration in live wood does not differ at north and at south but its net content is larger for CWD at northern ecosystems due to the higher volume density of live wood at the north. Concentration of mobile organic matter depends on decomposition class of CWD (r=0.72). CWD from southern ecosystems accumulate larger amount of humification products than that one from northern forests.
At northern latitudes CWD released larger amount of carbon and nutrients during decomposition, while southern ecosystems are characterized by nutrient immobilization and less carbon losses from CWD.
We conclude that CWD in northern and southern ecosystems play a different role in biogeochemical cycles. Logs of pine, spruce and fir in southern ecosystems are less chemically altered at the same decomposition stages than CWD of larch and spruce in northern forests, and immobilize significant amounts of nutrients. In contrast, CWD in northern ecosystems appears to be an important source of carbon and nutrient release to the soil and soil solutes.

 

Keywords : Coarse woody debris, Carbon and nutrients, Mobile and immobile organic constituents

 

 

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