CONCENTRATION OF CO2 UNDER SNOW COVER AND THE WINTER ACTIVITY OF THE SNOW BLIGHT FUNGUS PHACIDIUM-INFESTANS

The winter activity of soil organisms and of the fungus Phacidium infe stans inoculated on excised Scots pine shoots was monitored by measuri ng CO2 concentrations under the snow cover. Other variables measured, relating to respiration, were the temperature under the shoot heaps an d the depth of snow cover. The concentrations were highest when the te mperature under the snow remained at a relatively high level during th e whole winter which also favoured respiration from P infestans. When the soil was covered with a thin layer of snow, the conditions did not favor a high respiration rate until the snow melt period.