Effects of drainage on substrate temperature and phenology of some trees and shrubs in an Alberta peatland

• Published in: Canadian Journal of Forest Research
• Main Authors: Lieffers, V. J., Rothwell, R. L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1987
• Subjects: Tamarack; Dwarf birch
• Online Access: http://dx.doi.org/10.1139/x87-019; http://www.nrcresearchpress.com/doi/pdf/10.1139/x87-019

A 50-ha portion of an intermediate fen in north central Alberta was drained in 1984. Study sites were established in the drained area and in an adjacent undrained area. In each site, seasonal water table depth and substrate and air temperatures were monitored. The drainage lowered the water table from 20 to 50 cm compared with the adjacent undrained site. Substrate of the drained area warmed above 0 °C slightly later than the undrained area but maximum summer temperatures were higher in the drained site. Temperatures in 1985 at the 10-cm depth of the drained site peaked in early August at 15–16 °C, 3–4 °C higher than the undrained site. Forty-five black spruce (Piceamariana (Mill.) B.S.P.), 45 tamarack (Larixlaricina (Du Roi) K. Koch), and 25 dwarf birch (Betulapumila L.) were tagged and examined twice weekly. For tamarack and dwarf birch, flowering and bud flush were significantly earlier by 2–6 days in the drained site. For black spruce, flowering was earlier in the drained site; bud flush, however, was earlier in the undrained site in 1985 but there were no differences between sites in 1986. For both black spruce and tamarack, the mean date at which individual trees reached 50% of total leader elongation was earlier in the drained site in both 1984 and 1985.