Breakdown of forest litter in relation to environmental factors

The rate of litter decay in forests has a pronounced effect on the availability of nutrients for tree growth. In extreme cases litter may be broken down and incorporated in the mineral soll within a year (mull) or it may accumulate for many years on top of the mineral substrate (mor) thus tying up nutrients. Various factors such as geology, topography, climate, soil mierofiora and fauna, vegetation and leaf properties (pH, buffering dapacity, mineral composition, tanning substances, N content or C/N) have been thought to control the formation of mull and mor. These factors have been reviewed and evaluated by Handley 5. In the present work, which was part of a research program on the rate and mechanism of eycling of matter in forest systems, litter production and breakdown in mull and mor in different seasons and years were compared. The results were related to differences in soil moisture, temperature, microbial population, ]itter feeding fauna, rates of breakdown of the main leaf components (cellulose and lignified tissue), and the soil eoncentration of CO2, the main product of litter decomposition.