Performance of vegetation on mined sands

• Main Author: Bliss, L. C.
• Format: Report
• Language: English
• Published: 1979
• Subjects: RMD OF-27; Trees; Jack Pine; Mycorrhizae; Climate; Alberta; Fort McMurray; Lookout
• Online Access: https://era.library.ualberta.ca/items/34046079-45ae-4f36-9179-76d1fd1845ad; https://doi.org/10.7939/R39B50

This reports covering the results of the 1977 research, adds significantly to the earlier findings. It is always difficult to predict long term plant responses on only a few years of data; in this case, only two years. Climatically the two summers (May - August) were very similar, with the mean monthly temperatures averaging 0.2°C lower in 1977. Precipitation was ~20% higher in 1977, cloud cover was also greater, and as a result, diffuse radiation was higher. Short wave and net radiation were similar to the previous year. Net radiation increased from 70 W m-2 in early March to a maximum 207 W m-2 in mid-June. Photosynthetically active radiation (PHAR) was about 50% of incoming radiation, similar to other temperate region studies. Summer climate of the Richardson lookout Station is similar to the long term summer climate at Fort McMurray. Temperatures for May through August were slightly warmer (0.4 to 1.3°C) at Richardson and precipitation is ~20 mm less than at Fort McMurray. There are also fewer summer days with precipitation at the research site (44 vs. 55 days). As found the previous year, little precipitation runs off these porous sands. During spring thaw. water runs down slope within the soil above the frozen soil layer. About 50% of total precipitation moves out of the rooting zone to greater soil depths and is therefore unavailable for plant growth. The Jack Pine forest and its limited understory use only 170-200 mm of water per year, yet soil water potentials seem to not drop below 1.0 MPa. Microclimate within a forest canopy is difficult to measure and this is further complicated by working on a slope. As in 1976, gradients of temperature, water vapour and wind were small within the forest canopy. The exchange surfaces for heat and water vapour are diffuse due to openness of the canopy and its slope position. In spite of this, the canopy acts as a \"surface layer\" for radiation. On nights with little cloud cover and light winds (0.5 to 0.8 m s-l) cold air drainage was greatest, resulting in ...