Long-term soil response to variable-retention harvesting in the EMEND (Ecosystem Management Emulating Natural Disturbance) experiment, northwestern Alberta

2014 ◽  
Vol 94 (3) ◽  
pp. 263-279 ◽  
Author(s):  
Barbara E. Kishchuk ◽  
Sylvie Quideau ◽  
Yonghe Wang ◽  
Cindy Prescott

Kishchuk, B. E., Quideau, S., Wang, Y. and Prescott, C. 2014. Long-term soil response to variable-retention harvesting in the EMEND (Ecosystem Management Emulating Natural Disturbance) experiment, northwestern Alberta. Can. J. Soil Sci. 94: 263–279. We report on soil responses to variable-retention (VR) harvesting from a large-scale experiment (>1000 ha). Samples were taken prior to treatment, and 1 and 6 yr after treatment under cover types representing the successional trajectory for boreal mixedwood forests in northwestern Alberta, Canada. Variable-retention harvesting at six overstory-retention levels [100 (control), 75, 50, 20, 10, and 0% (clearcut)] were applied to 10-ha experimental units under four cover types: deciduous-dominated (80–95% trembling aspen); deciduous-dominated with coniferous understory (80–95% trembling aspen with white spruce understory at 60–80% of full stocking); mixed coniferous-deciduous (35–65% of each); and coniferous-dominated (80–95% white spruce). Only a few clear differences in soil properties attributable to VR harvesting were evident 6 yr post-harvest: (1) both extractable NH4-N in forest floor and 0–7 cm mineral-soil, and forest floor exchangeable K decreased with increasing canopy removal, and (2) forest floor exchangeable Ca increased with canopy removal. There was a decreasing trend in forest floor and mineral soil C (kg ha−1) in undisturbed stands between 1998 and 2005. Differences in soil properties among cover types included higher pH and N concentration in forest floors, and higher cation exchange capacity and exchangeable Ca and Mg in mineral soils in deciduous-dominated stands. Deciduous-dominated stands appear to have distinct soil properties that change under stand development.

1987 ◽  
Vol 17 (12) ◽  
pp. 1557-1564 ◽  
Author(s):  
R. D. Kabzems ◽  
K. Klinka

Previous attempts to characterize soil nutrient regimes of forest ecosystems have been qualitative evaluations utilizing vegetation and (or) topographic features, morphological soil properties, and mineralogy of soil parent materials. The objective of this study was to describe and provide initial data for quantitative classification of soil nutrient regimes in some Douglas-fir ecosystems on southern Vancouver Island. A multivariate classification using forest floor plus mineral soil mineralizable N and exchangeable Mg quantities was proposed for the four nutrient regimes (poor, medium, rich, and very rich) recognized in this study. Significant differences in mineralizable and total N existed between the four identified soil nutrient regimes. The previous N fertilization of two study sites did not seem to change soil N status sufficiently to alter the classification. The differences in nutrient availability were more distinct when forest floor and mineral soil properties, expressed on an areal basis, were summed. There were no significant differences in exchangeable Ca and Mg for the poor and medium soil nutrient regimes. The humus form of the forest floor was an important characteristic for identifying soil nutrient regimes in the field; however, the nutrient quantities of the forest floor reflected differences in bulk density and depth and did not effectively distinguish between regimes.


2020 ◽  
Vol 66 (6) ◽  
pp. 761-769
Author(s):  
Matt Busse ◽  
Ross Gerrard

Abstract We measured forest-floor accumulation in ponderosa pine forests of central Oregon and asked whether selected ecological functions of the organic layer were altered by thinning and repeated burning. Experimental treatments included three thinning methods applied in 1989 (stem only, whole tree, no thin—control) in factorial combination with prescribed burning (spring 1991 and repeated in 2002; no burn—control). Forest-floor depth and mass were measured every 4–6 years from 1991 to 2015. Without fire, there was little temporal change in depth or mass for thinned (270 trees ha−1) and control (560–615 trees ha−1) treatments, indicating balanced litterfall and decay rates across these stand densities. Each burn consumed 50–70 percent of the forest floor, yet unlike thinning, postfire accumulation rates were fairly rapid, with forest-floor depth matching preburn levels within 15–20 years. Few differences in forest-floor function (litter decay, carbon storage, physical barrier restricting plant emergence, erosion protection) resulted from thinning or burning after 25 years. An exception was the loss of approximately 300 kg N ha−1 because of repeated burning, or approximately 13 percent of the total site N. This study documents long-term forest-floor development and suggests that common silvicultural practices pose few risks to organic layer functions in these forests. Study Implications: Mechanical thinning and prescribed fire are among the most widespread management practices used to restore forests in the western US to healthy, firewise conditions. We evaluated their effects on the long-term development of litter and duff layers, which serve dual roles as essential components of soil health and as fuel for potential wildfire. Our study showed that thinning and burning provided effective fuel reduction and resulted in no adverse effects to soil quality in dry ponderosa pine forests of central Oregon. Repeated burning reduced the site carbon and nitrogen pools approximately 9–13 percent, which is small compared to C located in tree biomass and N in mineral soil. Litter accumulation after burning was rapid, and we recommend burning on at least a 15–20-year cycle to limit its build-up.


2012 ◽  
Vol 88 (03) ◽  
pp. 306-316 ◽  
Author(s):  
Richard Kabzems

Declines in forest productivity have been linked to losses of organic matter and soil porosity. To assess how removal of organic matter and soil compaction affect short-term ecosystem dynamics, pre-treatment and year 1, 5 and 10 post-treatment soil properties and post-treatment plant community responses were examined in a boreal trembling aspen (Populus tremuloidesMichx.)-dominated ecosystem in northeastern British Columbia. The experiment used a completely randomized design with three levels of organic matter removal (tree stems only; stems and slash; stems, slash and forest floor) and three levels of soil compaction (none, intermediate [2-cm impression], heavy [5-cm impression]). Removal of the forest floor initially stimulated aspen regeneration and significantly reduced height growth of aspen (198 cm compared to 472–480 cm) as well as white spruce (Picea glauca [Moench] Voss) height (82 cm compared to 154–156 cm). The compaction treatments had no effect on aspen regeneration density. At Year 10, heights of both aspen and white spruce were negatively correlated with upper mineral soil bulk density and were lowest on forest floor + whole tree removal treatments. Recovery of soil properties was occurring in the 0 cm to 2 cm layer of mineral soil. Bulk density values for the 0 cm to 10 cm depth remained above 86% of the maximum bulk density for the site, a soil condition where reduced tree growth can be expected.


Soil Research ◽  
2016 ◽  
Vol 54 (7) ◽  
pp. 847
Author(s):  
N. R. Hulugalle ◽  
T. B. Weaver ◽  
L. A. Finlay ◽  
V. Heimoana

Treated sewage effluent may contain large amounts of nitrogen and phosphorus, and moderate to high amounts of salts. With good management, it can be used as a source of irrigation water and nutrients for a range of crops and soils under different climatic conditions and irrigation systems. However, there are few long-term studies of irrigation with treated sewage effluent in swelling soils such as Vertosols. This study was established in 2000 on a cotton farm near Narrabri, north-western New South Wales, to assess long-term (14-year) changes in soil salinity, sodicity and carbon storage in a self-mulching, medium-fine, grey Vertosol under conservation farming and furrow-irrigated with tertiary-treated sewage effluent and stored rainfall runoff. Experimental treatments in 2000–02 were gypsum applied at a rate of 2.5t/ha in June 2000 and an untreated control. In 2003–13, the gypsum-treated plots received a single pass with a combined AerWay cultivator and sweeps to ~0.15m depth before sowing cotton; in the control plots, wheat stubble was undisturbed. By retaining significant amounts of crop residues on the soil surface, both practices are recognised as conservation farming methods. Parameters for water sampled from the head-ditch during each irrigation included electrical conductivity (ECw), pHw, concentrations of cations potassium (K+), calcium (Ca2+), magnesium (Mg2+) and sodium (Na+), and sodium adsorption ratio (SAR). Parameters for soil sampled to 0.6m depth before sowing cotton were pH (0.01M CaCl2), salinity (EC of 1:5 soil:water suspension), bulk density, soil organic carbon (SOC), exchangeable Ca, Mg, K and Na, exchangeable sodium percentage (ESP) and electrochemical stability index (ESI). SOC storage (‘stocks’) in any one depth was estimated as the product of bulk density, sampling depth interval and SOC concentration. Management system had little or no effect on cotton lint yields and the soil properties measured. Major changes in soil properties were driven by a combination of irrigation water quality and seasonal variations in weather. The cultivated treatment did not degrade soil quality compared with the control and may be an option to control herbicide-resistant weeds or volunteer Roundup-Ready cotton. Irrigation water was alkaline (average pHw 8.9), moderately saline (average ECw 1.0dS/m) and potentially highly dispersive (average SAR 12.1). Long-term irrigation with tertiary-treated sewage effluent resulted in sodification (ESP > 6) at all depths, alkalinisation at 0–0.10 and 0.30–0.60m, and accumulation in the surface 0.10m of Ca and K. Average ESP at 0–0.6m depth increased from 3.8 during 2000 to 13.2 during 2013. Sodification occurred within a few years of applying the effluent. Exchangeable Ca at 0–0.10m depth increased from 19cmolc/kg during 2000 to 22cmolc/kg during 2013, and exchangeable K from 1.5cmolc/kg during 2000 to 2.1cmolc/kg during 2013. Drought conditions caused an increase in salt accumulation, alleviated by a subsequent period of heavy rainfall and flooding. The reduction in salinity was accompanied by a fall in exchangeable Mg concentrations. Salinity and exchangeable Mg concentration were strongly influenced by interactions between seasonal rainfall (i.e. floods and drought) and the quality of the effluent, whereas ESP and exchangeable K concentration were not affected by variations in seasonal rainfall. SOC stocks declined until the flooding events but increased thereafter.


1995 ◽  
Vol 25 (5) ◽  
pp. 833-837 ◽  
Author(s):  
CM. Preston ◽  
D.J. Mead

To follow the movement and transformations of litter-fall N in a forest ecosystem, Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) foliage labelled with 15N was mixed into the forest floor and left to decompose in steel cylinders of 15 cm diameter X 60 cm length. There were four treatments: 15N-labelled foliage only, foliage plus 200 kg N•ha−1 as urea or NH4NO3, and unamended control. The addition of fertilizer N had no significant effects on 15N recovery or distribution in the soil profile. The overall recovery of 15N to 60 cm depth was 53.7%, 24.9%, and 19.9% after 1, 3, and 7.5 years, respectively. After the first year almost all of the recovered 15N was in the L layer. At 3 years, a higher proportion was found in the FH layer, and by 7.5 years, approximately one-third of the 15N was found in mineral soil horizons. There was very little recovery of 15N in inorganic form (1% or less) after 1 year; in subsequent years inorganic N was found at background levels. Recoveries in soil after 1 and 3 years were similar to those reported for 15N added as inorganic fertilizer in the absence of plant uptake. However, very low losses in the next sampling period (3 to 7.5 years) indicated stabilization of 15N in increasingly recalcitrant forms.


1987 ◽  
Vol 17 (12) ◽  
pp. 1577-1584 ◽  
Author(s):  
A. M. Macadam

Soil samples were taken before and 9 and 21 months after the operational broadcast burning of logging slash in two clear-cuts in the Sub-boreal Spruce Zone of central British Columbia. Average slash consumption on the two clear-cuts was estimated from line intersect samples at 20 and 24 t/ha and forest floor depth was reduced by 28 and 36%. Nine months after burning, soil N had decreased by 376 kg/ha (18% of preburn levels) while available P had increased by 37–157 kg/ha. Burning resulted in substantial increases in forest floor base saturation, pH, exchangeable Ca and Mg, and available P. Changes within the 0–15 and 15–30 cm mineral soil layers were variable and in general less pronounced. Significant positive correlations were observed between the consumption of large fuels and postburn changes in forest floor pH and exchangeable Ca and Mg. Changes in forest floor N were negatively correlated with amounts of fine slash consumed. A strongly negative correlation was observed between forest floor depth of burn and changes in forest floor exchangeable K concentrations.


Soil Systems ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 38
Author(s):  
Lelde Jansone ◽  
Klaus von Wilpert ◽  
Peter Hartmann

In the state of Baden-Wuerttemberg, Southwest-Germany, a large-scale forest liming trial was government-funded in 1983 and a lime treatment was carried out in autumn 1983 until early winter 1984. Repeated liming was applied in 2003. The limed sites and adjacent control plots were surveyed repeatedly: in 2003 before the second lime application and again in 2010 and 2015. Research of this scope presents a rare opportunity to evaluate firstly the long-term development of acidified soils with their potential for natural recovery on established control plots, and secondly the long-term effects of repeated lime application—at a collective of study sites of various growth regions and soil properties. A natural recovery in soil pH was observed since 2003, on average limited to an increase of 0.2–0.4 pH units in the forest floor and 0.1–0.3 pH units in the mineral soil until 2015. The majority of the organic layers still show very strong or extreme acidity with a pH value 3.9 on average and in the mineral soil with pH values between 3.8 and 4.6 on average. The exchangeable cations calcium and magnesium slightly increased also, although the base saturation remained <20% by 2015. The exchangeable acid cation concentrations indicated no significant changes and thus no recovery. The lime treatment greatly accelerated the rise in pH by 1.2–1.3 units and base saturation by 40–70% in the organic layer, as well as 0.3–1.2 pH units and base saturation by 7–50% in mineral soil. These effects were decreasing (yet still significant) with depth in the measured soil profile as well as with time since last treatment. Changes in soil cation exchange capacity after liming were significant in 0–5 cm mineral soil, below that they were negligible as the significant increase in base cations were accompanied by decreasing acid cations aluminum and iron (III) especially in the upper soil profile. Additionally, a decrease of forest floor and an enrichment of organic carbon and nitrogen in the mineral topsoil tended to follow liming at some sites. Overall the liming effects had a high variability among the study sites, and were more pronounced in the more acidic and coarser textured sites. Liming of acidified forest soils significantly adds to natural recovery and therefore helps to establish greater buffering capacities and stabilize forest nutrition for the future.


1995 ◽  
Vol 71 (1) ◽  
pp. 59-65 ◽  
Author(s):  
A. C. Balisky ◽  
P. Salonius ◽  
C. Walli ◽  
D. Brinkman

Concepts of planted seedling root morphology and root location are discussed in the context of reforestation in British Columbia. Comparison of root form and location between natural and planted seedlings reveals profound differences. Unnatural root morphology and delayed development of nursery-produced rooting systems, coupled with current planting techniques that emphasize vertical orientation of roots in mineral soil horizons, may exacerbate harsh microenvironmental site conditions. Inappropriate root systems may inhibit optimal seedling function and compromise long-term stand stability. The forest floor is seen as an appropriate rooting medium to which planted seedlings should be allowed ready access. A change in the biological geometry (direction and depth of root development) of the planted root system may enhance survival, establishment, and growth. The promotion of more natural, lateral, surface rooting at the organic/mineral soil interface is proposed. Site-specific root morphologies and planting strategies may be required. Key words: regeneration silviculture, tree-planting, target seedling stocktype, root egress, root morphology, root location, forest floor, soil temperature, soil moisture, frost heaving, soil nutrients, mycorrhizae, site preparation, alternative stocktypes


2017 ◽  
Vol 47 (8) ◽  
pp. 1140-1144 ◽  
Author(s):  
Cindy E. Prescott ◽  
Anya Reid ◽  
Shu Yao Wu ◽  
Marie-Charlotte Nilsson

Mechanical site preparation is assumed to reduce soil C stocks by increasing the rate at which the displaced organic material decomposes, but the evidence is equivocal. We measured rates of C loss of forest-floor material in mesh bags either placed on the surface or buried in the mineral soil at four sites in different regional climates in British Columbia. During the 3-year incubation, buried forest-floor material lost between 5% and 15% more C mass than material on the surface, with the greatest difference occurring at the site with the lowest annual precipitation. Studies of the long-term fate of buried and surface humus are needed to understand the net effects of site preparation on soil C stocks.


Sign in / Sign up

Export Citation Format

Share Document