Webinar - Tree Growth in Wooded Fens: Living Above the Flood

Victor Lieffers
Resource Date:

Moderate to rich fens covered with tamarack and black spruce cover large areas of Alberta. These peatlands are nearly pH neutral and are characterized by hummock-hollow topography where the hummocks are formed by several species of Sphagnum moss that tend to develop dense peat deposits elevated above the normal water table. This presentation presents research done over more than 30 years that describes some features of peatlands that influence tree growth in natural fens when fen hydrology is affected by either road building or other industrial activities. Roots of the conifer must be maintained above the usual water table. Raising water table height may kill trees while drainage of peatlands stimulates trees growth as much as four-fold compared to trees on normal fens. As peatlands are often critical habitat for caribou, the oil and gas seismic lines and drilling pads in these areas have recently been targeted for restoration. The presentation will also discuss ways that the hummock-hollow topography can be renewed in these highly disturbed areas in order to restore the tree cover on fens.