The relationship between soil temperature and the plant cover of a lichen dominated raised beach system in subarctic Ontario

Abstract

<p>Sqil temperature measurements were made under different plant covers to the base of the rooting zone of the raised beaches of the Hudson Bay coastal tundra region to determine the relationship between plant cover and the soil thermal regime. Two methods of description were used for quantitative comparison of temperature; 1) linear regression of daily averages and Fourier amplitudes over the field season to dermine near-surface differences in energy entering the soil under different plant covers and 2) a soil temperature model was constructed to separate physical influences over soil temperature from that of the plant cover. It was found that plant density had some control over the amount of energy transferred to the soil, causing a maximum difference of 7℃ in the upper layers between different plant covers. From the modelling process it was found that the humus layer had essentially no effect in the transfer of energy throughout the rooting zone during the summer months and it was postulated that the observed difference in soil temperature between sites of different plant cover was due to a differential rate of spring thaw caused by the different thickness of humus between sites.</p>