| Mean annual ground temperatures were measured at 28 spruce-forest sites in the Mackenzie Delta, to determine if differences in surface conditions between spruce-forest communities lead to differences in mean annual ground temperature. Surface conditions, including vegetation, organic-layer depth, and snow cover, were measured. Mean annual ground temperatures ranged from -0.6 to -2.9°C, and were negatively correlated with white spruce tree size, suggesting that canopy cover and the resulting interception of snow and radiation explain some of the variation. Ground temperature is also likely related to organic-layer depths and the presence of numerous water bodies. Spruce/alder-bearberry communities had thin organic layers, relatively open canopies, frequent flooding, and mean annual ground temperatures that were significantly higher than those of the other communities (-0.6 to -1.5°C). Mean annual ground temperatures at two sites in the central delta have increased by 0.3 and 0.9°C over the last 35 years in association with climate warming. |
