The impacts of forest harvest and wildfire on soils and hydrology in temperate forests: A baseline to develop hypotheses for the Boreal Plain

Abstract

This component of the Forest Riparian and Watershed Disturbance (FORWARD) project evaluates soils in burned, harvested, and undisturbed watersheds to quantify effects of disturbance on forest soils in the Boreal Plain. The current knowledge of disturbance effects on soils is reviewed, with a focus on temperate ecosystems, to generate the following hypotheses to be tested in field studies. Harvest and fire should affect surface horizons more than mineral horizons. Forest harvest should affect soils most through compaction, the degree being mediated by soil texture, soil moisture, and harvest operations. Nutrient export will likely increase from logged watersheds, with changes in microbial processes being more strongly associated with nitrogen (N) losses and erosional processes more strongly linked to phosphorus (P) losses. Effects of fire on Boreal Plain soils will increase with fire severity. Coarser soils after fire should be subject to hydrophobicity, erosion, and low infiltration rates. Chemical changes should include increased solubility of oxidized cations. N losses should exceed P losses and be due to volatilization and leaching of mineralized N compounds. Particulate P should comprise P loss; although P availability may increase after fire, soluble P movement from the forest environment will be limited by P uptake by soils. Key words: watershed disturbance, forest soils, forest fire, forest harvest, soil properties, nutrient cycling.

Soil and plant legacies associated with harvest trails in boreal black spruce forests

“…Soil compaction influences the number and continuity of macropores, disrupting air and water balance (Greacen and Sands, 1980), which may in turn affect microbial processes (Ballard, 2000). Skid trails may be characterized, therefore, by restricted root growth, poor drainage and aeration, as well as higher surface runoff and erosion (Startsev and McNabb, 2000;Chanasyk et al, 2003). Hence, understanding the long-term effects of harvest trail compaction and scarification on forest floor nutrient availability, microbial dynamics and competing vegetation is important for elucidating the influence of careful logging and scarification in longterm ecosystem resilience and functioning.…”

Effects of Wildfire and Harvest Disturbances on Forest Soil Bacterial Communities

“…Consequently, soil aggregates disintegrate, releasing clay and silt particles that plug soil pores and reduce infiltration capacity. Increased fluctuations in soil temperature and moisture follow harvesting because of the loss of the shading overstory (10,19). Increased availability of magnesium (19) as well as short-term increases in NH 4 ϩ (6) has been reported for clear-cut treatments.…”

“…A major result of harvesting is the compaction of forest soils (10). Consequently, soil aggregates disintegrate, releasing clay and silt particles that plug soil pores and reduce infiltration capacity.…”

Changes to flood peaks of a mountain river: implications for analysis of the 2013 flood in the Upper Bow River, Canada

“…Fire is recognized as being important to the grassland ecosystem (Ogilvie, ; Day, ; Stringer, ) and also to the elk introduced to the park (White et al , ; White, ). River basins directly impacted by fire exhibit a variety of hydrological responses (Moody and Martin, ; Chanasyk et al , ; Mahat et al , ; Springer et al , ), including hydrophobicity and decreased infiltration (Robichaud ). Evergreen forests intercept and sublimate a large fraction of winter snowfall (Pomeroy et al , ) and slow snowmelt substantially (Ellis et al , ).…”