Qualitative and quantitative studies of bacteria colonizing Picea sitchensis litter

Bacterial and actinomycete populations in the litter layers of a spruce forest soil were investigated. Most bacteria were found in the H layer, the fewest in the F layer but it was not possible to relate the distribution of the population as a whole to any of the environmental factors studied. However, the numbers of neutrophilic streptomycetes and thermoactinomycetes decreased down the litter profile whereas the number of acidophilic streptomycetes increased. Over 90% of 525 randomly-selected isolates were identified to the genera Anhrobacter, Bacillus, Micrococcus and Streptomvces. There was some evidence that the litter layers could be defined by their bacterial, and to a lesser extent, actinomycete flora.