Ten‐year water table recovery after clearcutting and draining boreal forested wetlands of eastern Canada

Abstract

Abstract:In boreal forested wetlands, the observed increase in the water table level after clearcutting (watering-up) is often a threat to sustained ecosystem productivity. Hydrologic recovery refers to the processes by which a water table progressively drops back to its initial level after the cut. In eastern Canada, drainage is used operationally after clearcutting wet sites in order to lower the water table level and accelerate hydrologic recovery. The objective of this study was to evaluate the duration of the watering-up caused by timber harvesting and the extent to which drainage affected the water table recovery on five peatlands and three hydromorphic mineral sites located in the St. Lawrence Lowlands of Québec (Canada). The mixed wood stands studied are dominated by balsam fir (Abies balsamea (L.) Mill.), eastern white cedar (Thuja occidentalis L.), and red maple (Acer rubrum L). Results indicate that, 10 years after clearcutting, water table levels in undrained plots are still 5 to 7 cm higher than the pre-cut levels. The slight recovery in water table level plateaued after the third year. Rainfall interception by vegetation was also monitored, and after 10 years had reached nearly 50% of the pre-cut rate. The immediate water table drawdown following drainage mitigated watering-up within 40 m of a ditch. The persistent watering-up observed in this study should encourage using sylvicultural systems adapted to boreal forested wetlands in order to prevent productivity loss and stand conversion.

Water table response to harvesting and simulated emerald ash borer mortality in black ash wetlands in Minnesota, USA

“…A number of studies have documented similar responses across a range of climate and site types, with increases in WT height similar to those observed here (Bliss and Comerford 2002;Xu et al 2002;Marcotte et al 2008;Pothier et al 2003). Clear-cutting largely caused a delay in WT drawdown that was more pronounced in 2012 than 2013, and heights were higher than the control in both years, primarily when the WT was deeper than 30 cm.…”

Impacts and prognosis of natural resource development on water and wetlands in Canada’s boreal zone

“…These elevated water tables can persist for many years. Pothier et al (2003) did not detect water table recovery five years after harvesting, and Marcotte et al (2008) found that water table levels in undrained plots were still 5-7 cm higher than the pre-cut levels 10 years after clearcutting, which was attributed to precipitation interception by vegetation being only 50% of the pre-harvest value.…”

“…Extensive research that occurred during eras when demand for forest products from peatlands was high and from the European experience has identified many beneficial management practices to minimize impacts on water resources. Although peatland draining following clearcutting or precommercial harvesting helps in the recovery from watering-up, it is considered a costly and remedial approach to the problem (Marcotte et al 2008). For example, drainage should be limited to the first cohort stand following harvesting (Lavoie et al 2005) because the improvement in tree growth may be relatively small without additional fertilization (Jutras et al 2002).…”

“…Partial and shelterwood cutting methods are among the best options, since watering-up was found to be roughly proportional to cutting intensity (Päivänen 1980;Pothier et al 2003). Partial cutting scenarios also conserve the vertical complexity of the stand that is essential to the recovery process (Marcotte et al 2008). This requires the use of appropriate equipment to minimize site disturbances while the ground is frozen (Locky and Bayley 2007).…”

Short-term impacts of soil preparation on greenhouse gas fluxes: A case study in nutrient-poor, clearcut peatland forest

“…However, watering up as a result of clearcutting (Heikurainen and Päivänen, 1970;Marcotte et al, 2008) may once again revive CH 4 production and emission from deep peat soils. One of the few studies relevant for our purposes examined the effects of clearcutting two nutrient-rich, drained peatland sites on CH 4 fluxes but found the changes to be negligible even though the WTL clearly rose, perhaps in part due to the slow re-establishment of methanogenic bacteria in old drainage areas (Huttunen et al, 2003).…”