Canadian Forest Service Publications
Early growth response in trees following peatland drainage. 2006. Hillman, G.R.; Roberts, J.J. Natural Resources Canada, Canadian Forest Service, Northern Forestry Centre, Edmonton, Alberta. Information Report NOR-X-408. 26 p.
Issued by: Northern Forestry Centre
Catalog ID: 26037
The growth of black spruce (Picea mariana (Mill.) BSP) and tamarack (Larix laricina (Du Roi) K. Koch) on two drained peatlands, at McLennan and Wolf Creek in central Alberta, was greater than on undrained control areas 9–10 years after drainage. On the drained plots, diameter growth was 1.6–2.3 times, height growth 2.7–3.5 times, and volume growth 4.4–9.7 times that on the undrained control plots. There were no clear differences in growth among various ditch spacings (30, 40, 50, and 60 m), and correlation between tree growth and distance of trees from the nearest ditch was poor. These results suggest that drawdown of the water table was sufficient to create unsaturated zones that facilitated equitable tree growth across the strips between ditches. Tree ring analyses revealed that increases in growth could begin as early as 3–4 years after drainage. The successful regeneration of black spruce on the control plots at McLennan and the reasonable size of black spruce and tamarack ingrowth on control plots suggest that both species are able to germinate and survive on wet sites initially, but high water tables inhibit their further development. Additional periodic measurements of both species are necessary to determine long-term growth patterns after drainage and to assess the financial feasibility of peatland drainage as a practical option in forest management.