scholarly journals Effects of vegetation and soil on evapotranspiration, flow regime, and basin storage in three nearby catchments in northeast Japan

2016 ◽  
Author(s):  
Shoji Noguchi ◽  
Tomonori Kaneko ◽  
Shin'ichi Iida ◽  
Wataru Murakami ◽  
Takanori Shimizu
Keyword(s):  
Flow Regime ◽  
Cryptomeria Japonica ◽  
Soil Depth ◽  
Forested Catchments ◽  
Sapwood Area ◽  
Stand Volume ◽  
Breast Height ◽  
Soil Storage ◽  
Order Of Magnitude ◽  
Soil Measurements

Abstract. Vegetation and soil determine evapotranspiration, flow regime, and basin storage in forested catchments. We conducted hydrological observations at three nearby catchments (catchments nos. 1, 2, and 3) in the Nagasaka experimental watershed located on the green tuff region in northeast Japan. Diameter-at-breast height (DBH) of all trees > 3 cm DBH was recorded. In addition, we measured soil depth at 170 locations and investigated 45 soil pits. Based on these detailed vegetation and soil measurements, we examined evapotranspiration, flow regime, and basin storage during the no-snow-cover period (May–November). More than 80.9 % of stands in the catchment were comprised of Cryptomeria japonica. Stand volume (122.0 m3 ha−1) and sapwood area (10.7 m2 ha−1) in catchment no. 3 were smaller than those in the other two catchments (no. 1: 255.7 m3 ha−1; 16.0 m2 ha−1, no. 2: 216.5 m3 ha−1; 14.2 m2 ha−1). Consequently, evapotranspiration was lower in catchment no. 3 than that in catchments nos. 1 and no. 2. In addition, low and scanty runoffs in catchment no. 3 were larger than those in nos. 1 and 2. The order of magnitude for soil storage was catchments no. 1 (104.2 mm) 

Assessment of AASHTO Load-Spreading Method for Buried Culverts and Proposed Improvement

2021 ◽  
pp. 036119812110215
Author(s):  
Michael G. Katona
Keyword(s):  
Ad Hoc ◽  
Soil Depth ◽  
Free Field ◽  
Peak Stress ◽  
Element Model ◽  
Surface Load ◽  
Accuracy Evaluation ◽  
Simple Modification ◽  
Homogeneous Half Space ◽  
Order Of Magnitude

AASHTO’s ad hoc method (AAM) for predicting free-field soil stress under a rectangular loading area is a simple and very useful tool for the analysis of buried culverts subject to vehicular wheel loads. AAM assumes the surface load spreads with soil depth into an ever-increasing rectangular area whose dimensions are controlled by a constant spread angle θ usually taken as 30°, denoted as AAM-30°. Both simplified and comprehensive culvert analysis procedures utilize AAM predictions for adjusting pressure distributions acting on the culvert periphery. Also, AAM-30° is routinely used to determine the two-wheel soil interaction depth, in which the combined effect of both axial wheels need to be considered. To date, a thorough accuracy analysis of AAM-30° has not been published in the open literature. This paper provides a unique and rigorous evaluation of AAM-30° using an exact solution from an elasticity-based model (EBM) of a homogeneous half-space with rectangular surface load. One key discovery is the depth parameter called y*, which is the soil depth at which AAM-30° peak-stress prediction exactly matches the exact EBM solution. Moreover, it is shown that y* may be determined by a simple, yet accurate formula that only depends on the square root of the load area. However, the investigation reveals that AAM-30° significantly underestimates peak stress in the shallow-depth zone 0 <  y < ½ y* by as much as 31.3% of the applied surface pressure. As this is a large nonconservative error it cannot be ignored. Accordingly, a very simple modification is introduced called AAM-θ*, in which θ* is a spread angle that linearly increases to 30° at soil depth ½ y* and thereafter θ* remains constant at 30°. An accuracy evaluation of AAM-θ* reveals an order of magnitude increase in accuracy in which the small residual error is conservative, not nonconservative. The paper concludes with discussions on applying AAM-θ* to the analysis of buried culverts when using either simple or finite element model solution procedures.

Sapwood–leaf area prediction equations for multi-aged ponderosa pine stands in western Montana and central Oregon

1995 ◽  
Vol 25 (9) ◽  
pp. 1553-1557 ◽  
Author(s):  
Kevin L. O'Hara ◽  
Narayanan I. Valappil
Keyword(s):  
Leaf Area ◽  
Ponderosa Pine ◽  
Western Montana ◽  
Prediction Equations ◽  
Sapwood Area ◽  
Breast Height ◽  
Conducting Tissue ◽  
Pine Trees ◽  
Pine Stands ◽  
Understory Trees

Ponderosa pine (Pinusponderosa Dougl. ex Laws.) frequently grows in pure, multi-aged stands throughout its range. Sapwood–leaf area prediction equations were developed for multi-aged, multi-strata ponderosa pine stands in western Montana and central Oregon. No significant differences were found between equations for trees from lower or upper strata, or between equations for all trees and equations for upper or lower strata trees in either study location. These results indicate overstory ponderosa pine trees do not require significantly greater sapwood conducting tissue per unit of leaf area than understory trees. Single variable models using only sapwood area at breast height are recommended.

scholarly journals Relative effects of dendrometers on the estimation of diameter at breast height, stand basal area and stand volume in uneven-aged northern hardwoods

2009 ◽  
Vol 85 (3) ◽  
pp. 446-452 ◽  
Author(s):  
François Guillemette ◽  
Marie-Claude Lambert
Keyword(s):  
Basal Area ◽  
Major Axis ◽  
Minor Axis ◽  
Northern Hardwoods ◽  
Parameter Estimates ◽  
Betula Alleghaniensis ◽  
Stand Volume ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Stand Basal Area

Four methods of estimating diameter at breast height (DBH) were used on 558 northern hardwood stems, located in 6, 0.25-ha plots, to compare their effects. The first method was a diameter tape reading and the second was a systematic reading, along a predefined axis, taken with a calliper. The last 2 methods were both obtained from the arithmetic mean of 2 different pairs of calliper readings taken at right angles. The first pair was directed along the major bole axis and the other pair along the minor axis. The 4 methods were compared in terms of mean tree diameter, plot basal area and plot volume. There were significant differences (p < 0.05) in parameter estimates among methods, and the differences varied according to species (Acer saccharum Marsh. and Betula alleghaniensis Britt.) and tree size class. Differences among methods were more evident for larger DBH classes, which contribute most to the significant differences observed for both the plot and stand basal area and volume. Overall, tree DBH, plot basal area and plot volume provided by these 4 methods ranked in this ascending order: mean calliper reading directed along the minor axis, systematic calliper reading, mean calliper reading directed along the major axis, and diameter tape. The difference in stand basal area or volume between the estimates obtained with a systematic calliper reading and a diameter tape was 1.1 m2/ha with a mean basal area of about 21 m2/ha, or 10.5 m3/ha with a mean stand volume of 169 m3/ha. Because of the magnitude of these differences, it is recommended the method of DBH estimation be specified in studies, to be careful when crossing databases or models using different methods of DBH estimation, and to always maintain the same method of DBH estimation when remeasuring a plot. Key words: northern hardwoods, dendrometer, diameter tape, calliper, caliper, DBH measurement, basal area, volume

scholarly journals N fluxes in two nitrogen saturated forested catchments in Germany: dynamics and modelling with INCA

2002 ◽  
Vol 6 (3) ◽  
pp. 383-394 ◽  
Author(s):  
J.-J. Langusch ◽  
E. Matzner
Keyword(s):  
Soil Depth ◽  
N Deposition ◽  
Model Complexity ◽  
N Saturation ◽  
Atmospheric N Deposition ◽  
Catchment Scale ◽  
Forested Catchments ◽  
Mineral N ◽  
N Fluxes ◽  
The Impact

Abstract. The N cycle in forests of the temperate zone in Europe has been changed substantially by the impact of atmospheric N deposition. Here, the fluxes and concentrations of mineral N in throughfall, soil solution and runoff in two German catchments, receiving high N inputs are investigated to test the applicability of an Integrated Nitrogen Model for European Catchments (INCA) to small forested catchments. The Lehstenbach catchment (419 ha) is located in the German Fichtelgebirge (NO Bavaria, 690-871 m asl.) and is stocked with Norway spruce (Picea abies (L.) Karst.) of different ages. The Steinkreuz catchment (55 ha) with European beech (Fagus sylvatica L.) as the dominant tree species is located in the Steigerwald (NW Bavaria, 400-460 m asl.). The mean annual N fluxes with throughfall were slightly higher at the Lehstenbach (24.6 kg N ha-1) than at the Steinkreuz (20.4 kg N ha-1). In both catchments the N fluxes in the soil are dominated by NO3. At Lehstenbach, the N output with seepage at 90 cm soil depth was similar to the N flux with throughfall. At Steinkreuz more than 50 % of the N deposited was retained in the upper soil horizons. In both catchments, the NO3 fluxes with runoff were lower than those with seepage. The average annual NO3 concentrations in runoff in both catchments were between 0.7 to 1.4 mg NO3-N L-1 and no temporal trend was observed. The N budgets at the catchment scale indicated similar amounts of N retention (Lehstenbach: 19 kg N ha-1yr-1 ; Steinkreuz: 17 kg N ha-1yr-1). The parameter settings of the INCA model were simplified to reduce the model complexity. In both catchments, the NO3 concentrations and fluxes in runoff were matched well by the model. The seasonal patterns with lower NO3 runoff concentrations in summer at the Lehstenbach catchment were replicated. INCA underestimated the increased N3 concentrations during short periods of rewetting in late autumn at the Steinkreuz catchment. The model will be a helpful tool for the calculation of "critical loads" for the N deposition in Central European forests including different hydrological regimes. Keywords: forest ecosystem, modelling, N budgets, N saturation, NO3 leaching, water quality, INCA

Equations for predicting sapwood area at crown base in southwestern Oregon Douglas-fir

1987 ◽  
Vol 17 (3) ◽  
pp. 236-241 ◽  
Author(s):  
Douglas A. Maguire ◽  
David W. Hann
Keyword(s):  
Cross Sections ◽  
Douglas Fir ◽  
Sapwood Area ◽  
Diameter At Breast Height ◽  
Total Height ◽  
Breast Height ◽  
Taper Models

Two basic taper models were analyzed for their ability to predict sapwood area at crown base. Sapwood areas were estimated on stem cross sections by measuring sapwood radii on the longest and perpendicular to longest axes and by assuming conformity to an ellipse. These data were collected on 2 to 14 points along the stems of 72 Douglas-fir trees in southwestern Oregon. Across the range in diameter at breast height, total height, and height to crown base, quadratic–quadratic segmented polynomials (T. A. Max and H. E. Burkhart. 1976. For. Sci. 25: 283–289) provided more consistent monotonie taper from breast height to crown base than F. A. Bennett and B. F. Swindel models (1972. USDA For. Serv. Res. Note SE-179). A model for predicting breast height sapwood area from only diameter at breast height, total height, and height to crown base is also presented.

scholarly journals Relationship between stem sapwood area and foliage area within the crown in Cryptomeria japonica.

1995 ◽  
Vol 24 (0) ◽  
pp. 47-50
Author(s):  
Hiroyuki WATANABE ◽  
Hiroyuki TAKIGUCHI ◽  
Kazukiyo YAMAMOTO ◽  
Shogo KOBAYASHI
Keyword(s):  
Cryptomeria Japonica ◽  
Sapwood Area

scholarly journals Psychotria hoffmansegiana (Willd ex Roem. & Schult.) Mull. Arg. and Palicourea marcagravii st. Hil. (Rubiaceae): potential for forming soil seed banks in a brazilian Cerrado

2007 ◽  
Vol 67 (3) ◽  
pp. 421-427 ◽  
Author(s):  
CG. Araújo ◽  
VJM. Cardoso
Keyword(s):  
Seed Bank ◽  
Soil Depth ◽  
Soil Seed Bank ◽  
Time Lapse ◽  
Brazilian Cerrado ◽  
Soil Seed Banks ◽  
Paulo State ◽  
Soil Storage ◽  
Different Depths ◽  
Persistent Soil Seed Bank

The germinability of artificially buried Psychotria hoffmansegiana and Palicourea marcagravii seeds in Cerrado soil was tested, with the aim of evaluating whether dispersed seeds may be able to form a soil seed bank. The assays were carried out at a Cerrado Reserve in São Paulo State, Brazil. Seed samples were placed in nylon bags and buried at two different depths and in two different sites. Samples were periodically exhumed and germination tests were performed with both exhumed and dry stored seeds. In general, soil storage favoured seed survival and germination when compared to dry stored seeds. The seed germination was little affected by soil depth and by burial environment. Seeds of both species remained viable for at least 13 months, considering the time lapse between the collection and the end of the germination tests. It was suggested that both species can potentially form a persistent soil seed bank in Cerrado.

scholarly journals Recent clonal reproduction of Cryptomeria japonica in a snowy region revealed by a survey of small-sized ramets

2020 ◽  
Vol 69 (1) ◽  
pp. 152-157
Author(s):  
Megumi K. Kimura ◽  
Takashi Nagashima ◽  
Tomohiko Kamitani ◽  
Hitoshi Sakio ◽  
Yoshihiko Tsumura
Keyword(s):  
Cryptomeria Japonica ◽  
Seedling Recruitment ◽  
Size Structure ◽  
Clonal Reproduction ◽  
The Other ◽  
Breast Height ◽  
Canopy Tree ◽  
Nuclear Microsatellite ◽  
Heavy Snow ◽  
Population Maintenance

Abstract Clonal reproduction may contribute to population maintenance in areas where disturbance caused by snow limits tree recruitment. To understand the importance of clonal reproduction in the population dynamics of canopy tree species, it is necessary to determine the frequency of clonal reproduction in the early stages of seedling establishment. We found 106 ramets, including “small-sized” ramets of less than 5 cm in diameter at breast height, aggregated within 4 patches in a 70 × 50 m plot and also identified 20 genets among these ramets with the use of nuclear microsatellite markers. The size structure of the ramets revealed an inverse J-shaped distribution, suggesting that continuous recruitment of new ramets occurs. However, the number of intermediate-sized ramets (around 10 cm DBH) at the present study site was small, suggesting that most new ramets die while they are still small by pressure from heavy snow. Of the 20 genets, 12 included one or more small-sized ramets, which indicated recent recruitment. Of the 12 genets, 3 included only a single small-sized ramet, which suggested seedling recruitment, whereas the other 9 included multiple ramets (39 small-sized ramets in total), which indicated clonal recruitment. The frequency (9/12) and number (39/9) of recent clonal recruits suggest that clonal reproduction effectively maintains the population of Cryptomeria japonica in snowy regions.

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