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 Specifics of soil temperature under winter wheat canopy

2013 ◽  
Vol 43 (3) ◽  
pp. 209-223 ◽  
Author(s):  
Jana Krčmáŕová ◽  
Hana Stredová ◽  
Radovan Pokorný ◽  
Tomáš Stdŕeda
Keyword(s):  
Soil Moisture ◽  
Winter Wheat ◽  
Soil Temperature ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
Soil Surface ◽  
Regression Equations ◽  
Experimental Plot ◽  
Near Surface ◽  
Soil Temperatures

Abstract The aim of this study was to evaluate the course of soil temperature under the winter wheat canopy and to determine relationships between soil temperature, air temperature and partly soil moisture. In addition, the aim was to describe the dependence by means of regression equations usable for phytopathological prediction models, crop development, and yield models. The measurement of soil temperatures was performed at the experimental field station ˇZabˇcice (Europe, the Czech Republic, South Moravia). The soil in the first experimental plot is Gleyic Fluvisol with 49-58% of the content particles measuring < 0.01 mm, in the second experimental plot, the soil is Haplic Chernozem with 31-32% of the content particles measuring < 0.01 mm. The course of soil temperature and its specifics were determined under winter wheat canopy during the main growth season in the course of three years. Automatic soil temperature sensors were positioned at three depths (0.05, 0.10 and 0.20 m under soil surface), air temperature sensor in 0.05 m above soil surface. Results of the correlation analysis showed that the best interrelationships between these two variables were achieved after a 3-hour delay for the soil temperature at 0.05 m, 5-hour delay for 0.10 m, and 8-hour delay for 0.20 m. After the time correction, the determination coefficient reached values from 0.75 to 0.89 for the depth of 0.05 m, 0.61 to 0.82 for the depth of 0.10 m, and 0.33 to 0.70 for the depth of 0.20 m. When using multiple regression with quadratic spacing (modeling hourly soil temperature based on the hourly near surface air temperature and hourly soil moisture in the 0.10-0.40 m profile), the difference between the measured and the model soil temperatures at 0.05 m was −2.16 to 2.37 ◦ C. The regression equation paired with alternative agrometeorological instruments enables relatively accurate modeling of soil temperatures (R2 = 0.93).

scholarly journals An improved representation of physical permafrost dynamics in the JULES land surface model

2015 ◽  
Vol 8 (1) ◽  
pp. 715-759 ◽  
Author(s):  
S. Chadburn ◽  
E. Burke ◽  
R. Essery ◽  
J. Boike ◽  
M. Langer ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Moisture ◽  
Active Layer ◽  
Land Surface ◽  
Climate Models ◽  
Surface Soil ◽  
Active Layer Thickness ◽  
Mean Square ◽  
Near Surface ◽  
Soil Temperatures

Abstract. It is important to correctly simulate permafrost in global climate models, since the stored carbon represents the source of a potentially important climate feedback. This carbon feedback depends on the physical state of the permafrost. We have therefore included improved physical permafrost processes in JULES, which is the land-surface scheme used in the Hadley Centre climate models. The thermal and hydraulic properties of the soil were modified to account for the presence of organic matter, and the insulating effects of a surface layer of moss were added, allowing for fractional moss cover. We also simulate a higher-resolution soil column and deeper soil, and include an additional thermal column at the base of the soil to represent bedrock. In addition, the snow scheme was improved to allow it to run with arbitrarily thin layers. Point-site simulations at Samoylov Island, Siberia, show that the model is now able to simulate soil temperatures and thaw depth much closer to the observations. The root mean square error for the near-surface soil temperatures reduces by approximately 30%, and the active layer thickness is reduced from being over 1 m too deep to within 0.1 m of the observed active layer thickness. All of the model improvements contribute to improving the simulations, with organic matter having the single greatest impact. A new method is used to estimate active layer depth more accurately using the fraction of unfrozen water. Soil hydrology and snow are investigated further by holding the soil moisture fixed and adjusting the parameters to make the soil moisture and snow density match better with observations. The root mean square error in near-surface soil temperatures is reduced by a further 20% as a result.

scholarly journals An improved representation of physical permafrost dynamics in the JULES land-surface model

2015 ◽  
Vol 8 (5) ◽  
pp. 1493-1508 ◽  
Author(s):  
S. Chadburn ◽  
E. Burke ◽  
R. Essery ◽  
J. Boike ◽  
M. Langer ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Moisture ◽  
Active Layer ◽  
Land Surface ◽  
Climate Models ◽  
Surface Soil ◽  
Active Layer Thickness ◽  
Mean Square ◽  
Near Surface ◽  
Soil Temperatures

Abstract. It is important to correctly simulate permafrost in global climate models, since the stored carbon represents the source of a potentially important climate feedback. This carbon feedback depends on the physical state of the permafrost. We have therefore included improved physical permafrost processes in JULES (Joint UK Land Environment Simulator), which is the land-surface scheme used in the Hadley Centre climate models. The thermal and hydraulic properties of the soil were modified to account for the presence of organic matter, and the insulating effects of a surface layer of moss were added, allowing for fractional moss cover. These processes are particularly relevant in permafrost zones. We also simulate a higher-resolution soil column and deeper soil, and include an additional thermal column at the base of the soil to represent bedrock. In addition, the snow scheme was improved to allow it to run with arbitrarily thin layers. Point-site simulations at Samoylov Island, Siberia, show that the model is now able to simulate soil temperatures and thaw depth much closer to the observations. The root mean square error for the near-surface soil temperatures reduces by approximately 30%, and the active layer thickness is reduced from being over 1 m too deep to within 0.1 m of the observed active layer thickness. All of the model improvements contribute to improving the simulations, with organic matter having the single greatest impact. A new method is used to estimate active layer depth more accurately using the fraction of unfrozen water. Soil hydrology and snow are investigated further by holding the soil moisture fixed and adjusting the parameters to make the soil moisture and snow density match better with observations. The root mean square error in near-surface soil temperatures is reduced by a further 20% as a result.

scholarly journals Aspect and soil textural controls on snowmelt runoff on forested Boreal Plain hillslopes

2011 ◽  
Vol 42 (4) ◽  
pp. 250-267 ◽  
Author(s):  
Todd Redding ◽  
Kevin Devito
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Surface Runoff ◽  
Soil Moisture Content ◽  
Mineral Soil ◽  
Sandy Soils ◽  
Slope Aspect ◽  
Snowmelt Runoff ◽  
Near Surface ◽  
Spring Snowmelt

Plot studies were conducted on a jack pine forest with sandy soil and aspen forests with sandy and loam soils to examine the controls of slope aspect, soil texture and fall soil moisture content on near-surface snowmelt runoff and infiltration. It was hypothesized that near-surface runoff would be greater from north-facing slopes on loam soils with increased fall soil moisture content. Fall soil moisture had no measurable effect on spring snowmelt runoff. Infiltration of snowmelt dominated (drainage coefficients 53–100%, median 87%) over near-surface runoff (runoff coefficients 1–65%, median 7%) for most plots. Runoff was related to concrete frost at the mineral soil surface. In contrast to the processes hypothesized, south-facing hillslopes with sandy soils generated greater runoff than north-facing slopes or sites with finer-textured soils. These results were due to greater concrete frost development resulting from periodic spring snowmelt and re-freezing in the upper soil. South-facing hillslopes with sandy soils featured lower canopy cover, allowing greater solar radiation to reach the snow surface which led to the formation of concrete frost and faster melt rates resulting in near-surface runoff. Where hillslopes are connected to receiving surface waters by continuous concrete frost, snowmelt runoff at the watershed scale may be enhanced.

Soil moisture reduces belowground heat flux and soil temperatures under a burning fuel pile

1986 ◽  
Vol 16 (2) ◽  
pp. 244-248 ◽  
Author(s):  
William H. Frandsen ◽  
Kevin C. Ryan
Keyword(s):  
Heat Flux ◽  
Soil Moisture ◽  
Heat Load ◽  
Mineral Soil ◽  
Temperature Reduction ◽  
Soil Temperatures ◽  
Mineral Soils ◽  
Heat Loads ◽  
Soil Interface ◽  
Soil Organics

A direct comparison of temperatures and heat loads was made between simulated duff-covered (~2 cm) and uncovered mineral soil beneath a burning fuel pile. Temperatures were recorded in the duff, at the duff – mineral soil interface, and at 1-cm intervals downward to a depth of 4 cm. Covering reduced the peak temperatures about 200 °C in dry mineral soil. Wet mineral soil covered with wet duff experienced a temperature reduction of over 500 °C. Temperatures in wet mineral soil did not exceed 90 °C and the heat load into the wet mineral soil was, on the average, 20% of the heat load into the dry mineral soil. Land managers wanting to minimize mortality of existing plants or loss of soil organics should strive to burn when mineral soils are approaching saturation near the surface.

Embryo growth in Alaskan white spruce seeds

1988 ◽  
Vol 18 (1) ◽  
pp. 64-67 ◽  
Author(s):  
John C. Zasada
Keyword(s):  
Soil Moisture ◽  
Seed Dispersal ◽  
Embryo Development ◽  
Growing Season ◽  
White Spruce ◽  
High Elevation ◽  
Seed Collection ◽  
Interior Alaska ◽  
Lower Elevation ◽  
Soil Temperatures

Embryo development in white spruce seeds was studied in five stands in interior Alaska. Cones and seeds were collected at 10- to 14-day intervals starting in mid-July and continuing until just before seed dispersal began. Significant differences were found in embryo development between stands, between trees within stands, and between cones within trees. The four stands at lower elevations produced seeds that had embryos filling 95% or more of the embryo cavity; this percentage was significantly higher than the highest elevation stand where embryos filled about 75% of the embryo cavity at the end of the growing season. Relative cotyledon length was generally greater than 25% in the lower elevation stands and slightly less than 20% in the high elevation stand. Although seed collection can be started when embryos fill 75% of the embryo cavity, the results of this and other studies suggest that collecting seeds when embryos are more mature will result in better quality seeds. Air and soil temperatures and soil moisture levels associated with embryo development are presented.

Soil Disturbance Following Whole-Tree Harvesting in North-Central Maine

1991 ◽  
Vol 8 (2) ◽  
pp. 68-72 ◽  
Author(s):  
David E. Turcotte ◽  
C. Tattersall Smith ◽  
C. Anthony Federer
Keyword(s):  
Mineral Soil ◽  
Soil Disturbance ◽  
Silt Loam ◽  
Site Productivity ◽  
Organic Horizons ◽  
On Line ◽  
Site Disturbance ◽  
Whole Tree Harvesting ◽  
Whole Tree ◽  
Tree Harvesting

Abstract Mechanical whole-tree harvesting can reduce site productivity if it results in excessive soil disturbance, which may both kill advanced regeneration and reduce the potential of the soil to support tree growth. Large feller-forwarders with wide, high flotation tires were designed to reduce soil disturbance, but they can cause excessive amounts of site disturbance if harvesting is conducted when soils are wet. The spatial distribution and severity of soil disturbance were determined on line transects after a spring whole-tree clearcut in northern Maine on the silt loam soils of the Chesuncook catena. Exposed mineral soil and deep wheel ruts occurred more frequently on somewhat poorly (37% of surface area) and poorly (42%) drained soil than on moderately well-drained soil (19%). This amount of site disturbance seems excessive and could reduce future site productivity due to removal of organic horizons and destruction of advanced conifer regeneration. Harvesting with large feller-forwarders on the poorly and somewhat poorly drained silt loam soils of this region should be discouraged in the spring and possibly during other periods of high soil water tables. North. J. Appl. For 8(2):68-72.

scholarly journals Variability of Snowmelt Runoff and Soil Moisture Recharge

1998 ◽  
Vol 29 (3) ◽  
pp. 179-198 ◽  
Author(s):  
T.E. Harms ◽  
D. S. Chanasyk
Keyword(s):  
Soil Moisture ◽  
Snow Water Equivalent ◽  
Slope Aspect ◽  
Major Influence ◽  
Spatial And Temporal Variability ◽  
Power Relationship ◽  
Snowmelt Runoff ◽  
Near Surface ◽  
Antecedent Conditions ◽  
Soil Temperatures

The spatial and temporal variability of snowmelt runoff and soil moisture recharge within small watersheds must be quantified for use in distributed parameter snowmelt models. Snowmelt runoff, over-winter changes in soil moisture and soil temperatures were monitored over three annual snowmelt periods on two reclaimed watersheds in central Alberta, Canada. Slope aspect had a major influence on fall soil antecedent conditions and soil temperature. The south-facing slopes produced snowmelt the earliest, cleared of snow the soonest, yielded the least amount of runoff and had the greatest gain in over-winter soil moisture. Over-winter change in soil moisture was minimal when fall soil moisture levels were greater than 75% relative saturation. The power relationship between infiltration and snow-water equivalent of Granger et al. (1984) was not verified in this study, likely due to mid-winter melts that altered near-surface soil moisture and subsequently enhanced snowmelt runoff.

Simulation of snow and soil water content as a basis for satellite retrievals

2012 ◽  
Vol 43 (5) ◽  
pp. 720-735 ◽  
Author(s):  
M. J. Sandells ◽  
G. N. Flerchinger ◽  
R. J. Gurney ◽  
D. Marks
Keyword(s):  
Soil Moisture ◽  
Data Assimilation ◽  
Soil Water ◽  
Surface Soil ◽  
Lower Boundary ◽  
Soil Heat Flux ◽  
Surface Soil Moisture ◽  
Near Surface ◽  
Soil Temperatures ◽  
Snow Mass

It is not yet possible to determine whether global snow mass has changed over time despite collection of passive microwave data for more than thirty years. Physically-based, but computationally fast snow and soil models have been coupled to form the basis of a data assimilation system for retrievals of snow mass and soil moisture from existing and future satellite observations. The model has been evaluated against observations of snow mass and soil temperature and moisture profiles from Reynolds Creek Experimental Watershed, Idaho. Simulation of snow mass was improved early in the season due to more realistic representation of soil heat flux, but led to an overestimation of snow mass later in the season. Soil temperatures were generally simulated well; freezing of the surface layers was not observed but was simulated, which affected soil water transport. Limited knowledge of the soil lower boundary conditions is acceptable for snow mass and surface soil moisture retrievals, although improvements are required for more accurate simulations of deeper soil moisture at this site. Development of a data assimilation framework to retrieve snow mass and near-surface soil moisture is discussed.

Site Damage from Mechanized Thinning in Southeast Alaska

1986 ◽  
Vol 3 (3) ◽  
pp. 94-97 ◽  
Author(s):  
Roy C. Sidle ◽  
Thomas H. Laurent
Keyword(s):  
Forest Soils ◽  
Mineral Soil ◽  
Sitka Spruce ◽  
Soil Disturbance ◽  
Western Hemlock ◽  
Root Damage ◽  
Southeast Alaska ◽  
Second Growth ◽  
Organic Horizons ◽  
Probable Infection

Abstract Damage to the site was assessed in a second-growth stand of western hemlock and Sitka spruce on Prince of Wales Island, Alaska, after thinning with a Menzi-Muck walking backhoe. The qualitative procedure used to assess disturbance of forest soils with organic horizons is outlined. Almost half of the area in thinning roads received some level of disturbance, but less than 1% of the total thinned area was heavily disturbed (mineral soil exposed) or heavily compacted during felling-bunching operations. Approximately 90% of the leave trees had some stem or root abrasion, although only 5% of these scars were >1 ft2. The most probable infection courts for fungi were split or severed roots, which occurred on 10% of the leave trees. Most soil disturbance, compaction, and root damage was caused by the metal pads on the front legs of the machine, or by abrasion by logs during bunching. North. J. Appl. For. 3:94-97, Sept. 1986.

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