Forest soil disturbance intervals inferred from soil charcoal radiocarbon dates

2003 ◽  
Vol 33 (12) ◽  
pp. 2514-2518 ◽  
Author(s):  
Daniel G Gavin
Keyword(s):  
Forest Soil ◽  
Forest Fires ◽  
Mineral Soil ◽  
Soil Disturbance ◽  
Organic Horizon ◽  
Radiocarbon Dates ◽  
Soil Charcoal ◽  
Old Growth Forest ◽  
Soil Disturbances ◽  
Tree Uprooting

Forest soil disturbance intervals are usually too long to measure using plot-based studies, and thus they are poorly understood. The mean soil disturbance interval (MSDI) in an old-growth forest on the west coast of Vancouver Island was estimated from radiocarbon dates of charcoal from organic and mineral soil horizons. Two assumptions are required to estimate the MSDI: (1) charcoal from forest fires is deposited within the organic horizon and eventually mixed into deeper mineral horizons by soil disturbances, and (2) the probability of soil disturbance is spatially homogeneous and affected only by the time since the last fire or the last soil disturbance. The MSDI is then estimated by the rate at which the proportion of undisturbed sample sites (determined by the proportion of sites with charcoal from the most recent fire in the organic horizon) decreases with increasing time since the last fire. Soil charcoal evidence of time since fire was determined at 83 sites using 141 radiocarbon dates. The estimated MSDI was greater on slopes (ca. 2010 years) than on terraces (ca. 920 years). The long periods between soil disturbances, especially on slopes, are consistent with other evidence from the study area that suggests infrequent tree uprooting is the predominant mode of soil disturbance.

Silvicultural treatments, microclimatic conditions and seedling response in Southern Interior clearcuts

1998 ◽  
Vol 78 (1) ◽  
pp. 115-126 ◽  
Author(s):  
R. L. Fleming ◽  
T. A. Black ◽  
R. S. Adams ◽  
R. J. Stathers
Keyword(s):  
Soil Moisture ◽  
Seedling Establishment ◽  
Initial Period ◽  
Mineral Soil ◽  
Soil Disturbance ◽  
Near Surface ◽  
Lower Elevation ◽  
Organic Horizons ◽  
Soil Temperatures ◽  
Microclimatic Conditions

Post-harvest levels of soil disturbance and vegetation regrowth strongly influence microclimate conditions, and this has important implications for seedling establishment. We examined the effects of blading (scalping), soil loosening (ripping) and vegetation control (herbicide), as well as no soil disturbance, on growing season microclimates and 3-yr seedling response on two grass-dominated clearcuts at different elevations in the Southern Interior of British Columbia. Warmer soil temperatures were obtained by removing surface organic horizons. Ripping produced somewhat higher soil temperatures than scalping at the drier, lower-elevation site, but slightly reduced soil temperatures at the wetter, higher-elevation site. Near-surface air temperatures were more extreme (higher daily maximums and lower daily minimums) over the control than over exposed mineral soil. Root zone soil moisture deficits largely reflected transpiration by competing vegetation; vegetation removal was effective in improving soil moisture availability at the lower elevation site, but unnecessary from this perspective at the higher elevation site. The exposed mineral surfaces self-mulched and conserved soil moisture after an initial period of high evaporation. Ripping and scalping resulted in somewhat lower near-surface available soil water storage capacities. Seedling establishment on both clearcuts was better following treatments which removed vegetation and surface organic horizons and thus enhanced microclimatic conditions, despite reducing nutrient supply. Such treatments may, however, compromise subsequent stand development through negative impacts on site nutrition. Temporal changes in the relative importance of different physical (microclimate) and chemical (soil nutrition) properties to soil processes and plant growth need to be considered when evaluating site productivity. Key words: Microclimate, soil temperature, air temperature, soil moisture, clearcut, seedling establishment

scholarly journals Tolerant hardwood natural regeneration 15 years after various silvicultural treatments on an industrial freehold of northwestern New Brunswick

2013 ◽  
Vol 89 (04) ◽  
pp. 512-524 ◽  
Author(s):  
Martin Béland ◽  
Bruno Chicoine
Keyword(s):  
New Brunswick ◽  
Natural Regeneration ◽  
Sugar Maple ◽  
Mineral Soil ◽  
Soil Disturbance ◽  
Betula Alleghaniensis ◽  
Yellow Birch ◽  
American Beech ◽  
Partial Cutting ◽  
Selection Cutting

We examined applicability of various partial cutting systems in order to regenerate tolerant hardwood stands dominated by sugar maple (Acer saccarhum), American beech (Fagus grandifolia) and yellow birch (Betula alleghaniensis) on northern New Brunswick J.D. Irving Ltd. freehold land. Sampling of 1065 one-m2 plots in 31 stands managed by selection cutting, shelterwood method and strip or patch cutting and in six control stands allowed a 15-year retrospective study of natural regeneration in stands of low residual densities and with minimal soil disturbance and no control of competing vegetation. Beech regeneration was most abundant in the patch cuts, yellow birch in shelterwood stands and sugar maple in the selection system areas. Results suggest that initial stand conditions influence the composition of the regeneration more than the prescribed treatment. At the stand scale (a few hectares), sugar maple recruitment was positively influenced by its proportion in the initial stand, and negatively by the cover of herbs and shrubs. Yellow birch regeneration was mainly affected by shrub competition. At the plot (1 m2) scale, mineral soil and decayed wood substrates and ground-level transmitted light were determinant factors for yellow birch regeneration. Beech-dominated stands were likely to regenerate to beech. A dense beech sucker understory was promoted in harvested patches. Areas with dense understory of American beech, shrubs, or herbs require site preparation to reduce interference either before or at the time of partial cutting. Shelterwood seed cutting and selection cutting should leave a residual of 12 m2/ha and 17 m2/ha respectively in seed trees uniformly distributed.

scholarly journals Evaluating Bayesian radiocarbon-dated event-count [REC] models for the study of long-term human and environmental processes

2020 ◽  
Author(s):  
William Christopher Carleton
Keyword(s):  
Forest Fires ◽  
Simulated Data ◽  
Radiocarbon Date ◽  
Radiocarbon Dates ◽  
New Class ◽  
Environmental Processes ◽  
Growth Decline ◽  
Marine Ingression ◽  
Event Times

Chronological uncertainty complicates attempts to use radiocarbon dates as proxies for processes like human population growth/decline, forest fires, and marine ingression. Established approaches involve turning databases of radiocarbon-date densities into single summary proxies that cannot fully account for chronological uncertainty. Here, I use simulated data to explore an alternate Bayesian approach that instead models the data as what they are, namely radiocarbon-dated event-counts. The approach involves assessing possible event-count sequences by sampling radiocarbon date densities and then applying MCMC to estimate the parameters of an appropriate count-based regression model. The regressions based on individual sampled sequences were placed in a multilevel framework, which allowed for the estimation of hyperparameters that account for chronological uncertainty in individual event times. Two processes were used to produce simulated data. One represented a simple monotonic change in event-counts and the other was based on a real palaeoclimate proxy record. In both cases, the method produced estimates that had the correct sign and were consistently biased toward zero. These results indicate that the approach is widely applicable and could form the basis of a new class of quantitative models for use in exploring long-term human and environmental processes.

scholarly journals Soil Disturbance and the Potential for Erosion After Mechanical Site Preparation

2002 ◽  
Vol 19 (1) ◽  
pp. 5-13 ◽  
Author(s):  
Jorge Alcázar ◽  
Paul M. Woodard ◽  
Richard L. Rothwell
Keyword(s):  
Soil Erosion ◽  
Mineral Soil ◽  
High Water ◽  
Soil Disturbance ◽  
Site Preparation ◽  
Treatment Area ◽  
Soil Movement ◽  
Mechanical Site Preparation ◽  
Physical Conditions ◽  
Water Contents

Abstract Physical soil properties created by three mechanical site preparation treatments (ripper ploughing, disc trenching, and blading) and a control were evaluated to determine the success of these different mechanical site preparation treatments in creating plantable microsites and to estimate the potential for soil erosion created by each treatment. Three sites with fine textured soils and high water contents near Whitecourt, Alberta, Canada), were selected for study. The topography at all sites was similar and characterized by slopes 3.7 to 20% in steepness and approximately 190 to 270 m in length extending from the height of land to stream bottoms. The number of planting sites and the soil characteristics suggest ripper ploughing as the best site preparation treatment in this study, with the hinge microsite as the preferred planting spot. All three treatments significantly improved the physical conditions of the soil compared to the control, although the differences among treatments were small. Soil erosion was observed on areas where blading and ripper ploughing exposed mineral soil. Gullies, which exposed the roots of seedlings, were created by water erosion in the blading treatment area. Sediment deposition in trenches was observed on ripper ploughed areas, and at times, seedlings within this treatment area were partially buried as a result of this soil movement.

Logging and soil disturbance in southeast British Columbia

1986 ◽  
Vol 16 (6) ◽  
pp. 1345-1354 ◽  
Author(s):  
R. Krag ◽  
K. Higginbotham ◽  
R. Rothwell
Keyword(s):  
Primary Source ◽  
High Elevation ◽  
Soil Disturbance ◽  
Slope Steepness ◽  
Forest Region ◽  
Cable Yarding ◽  
Soil Disturbances ◽  
Operational Factors ◽  
Primary Hypothesis ◽  
Slope Class

The purpose of this study was to document and to analyze extent, type, and degree of soil disturbance on ground-skidded and cable-yarded cutovers. The primary hypothesis was that ground skidding on steep, high elevation sites generates more soil disturbance than cable yarding. Thirty-one cutovers were surveyed in the Nelson Forest Region: 25 logged by ground skidding and 6 by cable yarding. Three replications were obtained for each season – slope class on ground-skidded sites. Cable-logged areas were also replicated three times, but only for season. Elevations of the cutovers ranged from 910 to 1970 m with an average of 1360 m. Slope steepness on cutovers ranged from 5 to 74%. Soil disturbance was significantly greater on ground-skidded than on cable-yarded cutovers, averaging 40–45% vs. 22–30%, respectively, regardless of season. Differences in soil disturbance between logging methods by season were small and not significant. Average soil disturbances for summer cable yarding and ground skidding were 30 and 45%, respectively, compared with 22 and 40% for winter operations. Analysis of soil disturbance by source revealed skidroads as the major cause of disturbance on ground-skidded cutovers, regardless of season. The primary source of disturbance on cable-yarded areas was yarding in the summer and haul roads in the winter. Ground skidding also caused more deep to very deep disturbance, averaging 30% in winter and 35% in summer compared with 18 and 14% on cable-yarded sites. For both methods deep and very deep disturbance were most common accounting for 75–80% of total disturbance. Extent of soil disturbance and slope steepness were not significantly related. The high variability in soil disturbance noted in this study was similar to other surveys. Most studies have attempted to associate such variation with major environmental factors but with little success. To fully explain soil disturbance, operational factors such as planning and layout of logging must be considered.

Response of lodgepole pine health to soil disturbance treatments in British Columbia, Canada

2015 ◽  
Vol 45 (8) ◽  
pp. 1045-1055 ◽  
Author(s):  
Anya M. Reid ◽  
William K. Chapman ◽  
John Marty Kranabetter ◽  
Cindy E. Prescott
Keyword(s):  
British Columbia ◽  
Organic Matter ◽  
Soil Compaction ◽  
Lodgepole Pine ◽  
Mineral Soil ◽  
Forest Health ◽  
Soil Disturbance ◽  
Base Saturation ◽  
Soil Productivity ◽  
Health Response

Soil disturbance from organic matter loss and soil compaction can impair site productivity, but less is known about whether these disturbances also affect forest health (defined here as the presence and severity of damaging pests and diseases, mortality, and overall vigour). We used six long-term soil productivity (LTSP) sites in the interior of British Columbia, Canada to test the effects of organic-matter removal and soil compaction on forest health, and to explore the relationship between forest health response and potential indicators of site sensitivity: mineral soil pH, base saturation, carbon to nitrogen ratio (C:N), carbon to phosphorus ratio (C:P), and calcium to aluminum ratio (Ca:Al). Visual forest health surveys were conducted on 5400 15 and 20 year old lodgepole pine (Pinus contorta Dougl. ex Loud.) trees. Soil disturbance treatments significantly affected forest health metrics, but this response typically differed among sites. Principle component analyses indicated the response of healthy trees was negatively related to soil base saturation, the response of dead or dying trees related to soil C:P, and the response of tree disease related to soil Ca:Al, pH, base saturation, and C:N. We found forest health response to soil disturbance varied among sites with relationships between response and soil chemical properties, suggesting a greater vulnerability of pine stands to disease with increasing soil acidity.

Prescribed Burning White Spruce Slash in Interior Alaska

1986 ◽  
Vol 3 (1) ◽  
pp. 16-18 ◽  
Author(s):  
John Zasada ◽  
Rodney Norum
Keyword(s):  
Organic Material ◽  
Prescribed Burning ◽  
Mineral Soil ◽  
White Spruce ◽  
Flood Plain ◽  
Organic Horizon ◽  
Forest Types ◽  
Mechanical Site Preparation ◽  
Interior Alaska ◽  
Soil Exposure

Abstract Broadcast burning following harvesting on flood-plain sites in Alaska substantially decreased residual organic material and increased exposed mineral soil. Two forest types were studied: white spruce/alder/feathermoss and white spruce/alder/lingenberry/feathermoss. The latter site contained permafrost. Fuel was reduced 67% and 81%, respectively; organic horizon thickness was decreased 43% to 2.9 in (7.4 cm) and 55% to 2.5 in (6.4 cm), respectively; and mineral soil exposure was 13% and 8%, respectively. Burning created good conditions for planting on both types. In addition, mechanical site preparation to increase mineral soil exposure appears to be necessary to achieve adequate, well-distributed regeneration from seed. North. J. Appl. For. 3:16-18, Mar. 1986.

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