Abstract:
Thirteen study sites on the floodplain and terraces ofthe lower Peace River, Wood Buffalo National Park,Canada, were examined for the effects of naturalforest succession and logging on physical and chemicalsoil properties. The principal changes in substratecharacteristics along the natural successional pathwaywere (i) development of a forest floor and (ii) burialof organic layers by floodwater deposition. Thephysical soil parameters of the forest floor andmineral soil were closely related to floodingfrequency, soil texture, stand closure, and forestfloor build-up. Significant differences in a number ofchemical soil properties between early (Barren Silt,Establishing) and late (Mature, Old-growth)successional stages were evident. The rising influenceof the developing plant community on chemical soilparameters was obvious. Organic carbon, totalnitrogen, cation exchange capacity, exchangeablecalcium, magnesium and potassium and extractablephosphorus level of forest floor and mineral soilswere highest in Mature sites; whereas pH and basesaturation were lowest. Physical and chemical soilproperties at three clear-cut sites were compared tosix undisturbed Mature/Old-growth stands. Removingvegetation had an effect on the physical soilproperties. A significant decrease in forest floornitrogen, cation exchange capacity, calcium andphosphorus occurred due to clear-cutting. Nosignificant change of chemical soil parameters wasobserved in the mineral soil at 0–20 cm depthfollowing harvesting. Significant impacts on chemicalsoil characteristics appeared to be limited to theforest floor. The absence of post-cutting sitepreparations makes the study area a useful benchmarkfor comparison with logged and scarified borealriparian sites elsewhere.
