Application of the Point-Count Method to Problems of Soil Morphology

Daniels, R. B.; Gamble, E. E.; Bartelli, Lindo J.; Nelson, L. A.

doi:10.1097/00010694-196808000-00012

Cited by 10 publications

(6 citation statements)

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“…For each horizon, soil thickness was recorded and 400-g samples were obtained for laboratory determination of permanent wilting point (PWP) and field capacity (FC) to estimate soil water retention capacity (Richards 1941). Percentage of stones of each soil horizon was estimated using the point-count method described by Daniels et al (1968). The soil water holding capacity was defined in Eq.…”

Section: Soil Water Holding Capacitymentioning

confidence: 99%

Leaf area and growth of Chilean radiata pine plantations after thinning across a water stress gradient

Ojeda

Rubilar

Montes

et al. 2018

N.Z. j. of For. Sci.

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Background: Pinus radiata D.Don has been established in a wide range of soils and climatic conditions, showing high variability in both leaf area and volume productivity. Previous research has shown that plantation yield is affected by water availability, but the majority of this work has been done in unthinned stands and provided little insight on the effect of water availability on the productivity of thinned plantations. In order to improve forest productivity for plantations under a climate change scenario, we must understand the effect of plantation management, including thinning on the relationships among available water, leaf area index, and productivity. The aim of this work is to evaluate the effect of site water availability on the leaf area production and consequent volume growth in thinned radiata pine plantations over a water availability gradient. Methods: The effect of site available water on leaf area production and consequent volume growth in thinned Pinus radiata plantations over a water availability gradient across five sites in central and southern-central Chile was determined. Results: Regression analysis revealed water deficit to be related to both leaf area index and volume growth accounting for 77 and 78% of the variation respectively. Eighty-one percent of the variation in volume growth was explained by the leaf area index. Results showed a growth efficiency of 5 m 3 ha −1 per unit of leaf area index. Conclusions: Strong linear positive relationships between site water availability, leaf area, and stand growth after thinning found in this research suggest that water is the key factor controlling current productivity of radiata pine plantations across sites. A simple and robust water index that is well correlated with leaf area and stand annual volume growth allows for the construction of a simple predictive model that may support management decisions for radiata pine plantations.

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Section: Soil Water Holding Capacitymentioning

confidence: 99%

Leaf area and growth of Chilean radiata pine plantations after thinning across a water stress gradient

Ojeda

Rubilar

Montes

et al. 2018

N.Z. j. of For. Sci.

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“…Alternatively, the point counting approach allows to extract information easily and to estimate the fractions of LUC from the APs as applied by e.g. Bellhouse (1981) and Daniels et al (1968). In this technique, different land covers that occur under the points of a grid superimposed on an area are being identified and counted (Bellhouse, 1981).…”

Section: Land Use/cover Analysis By the Point Counting Methodsmentioning

confidence: 99%

“…The fractions of the LUC classes, described as the density or weight of LUC, were calculated for each scene (AP and GE) as the ratio of the total number of points for each class to the total number of points of all LUC counted per AP/GE (Daniels et al, 1968). Points where the LUC is unknown or invisible on APs due to the clouds or damage of the photographs were excluded from further analyses and the corresponding points on GE omitted, too.…”

Section: Data Analysesmentioning

confidence: 99%

Changes in land use/cover mapped over 80 years in the Highlands of Northern Ethiopia

et al. 2018

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Despite many studies on land degradation in the Highlands of Northern Ethiopia, quantitative information regarding long-term changes in land use/cover (LUC) is rare. Hence, this study aims to investigate the LUC changes in the Geba catchment (5142 km 2), Northern Ethiopia, over 80 years (1935-2014). Aerial photographs (APs) of the 1930s and Google Earth (GE) images (2014) were used. The point-count technique was utilized by overlaying a grid on APs and GE images. The occurrence of cropland, forest, grassland, shrubland, bare land, built-up areas and water body was counted to compute their fractions. A multivariate adaptive regression spline was applied to identify the explanatory factors of LUC and to create fractional maps of LUC. The results indicate significant changes of most types, except for forest and cropland. In the 1930s, shrubland (48%) was dominant, followed by cropland (39%). The fraction of cropland in 2014 (42%) remained approximately the same as in the 1930s, while shrubland significantly dropped to 37%. Forests shrank further from a meagre 6.3% in the 1930s to 2.3% in 2014. High overall accuracies (93% and 83%) and strong Kappa coefficients (89% and 72%) for point counts and fractional maps respectively indicate the validity of the techniques used for LUC mapping.

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“…The foregoing discussion of sampling error suggests that a single sherd is capable of reliably representing the ceramic vessel from which it was derived in a comparative petrographic analysis so long as we allow for an error factor of ±3.5 percent. While this conclusion must be tentative, pending experimentation with a wider range of ceramic pastes, it nonetheless is supported strongly in the literature on estimating the theoretical reliability of point-count analyses (Daniels et al 1968;[Vol. 54, No.…”

Section: Sources Of Error In Point-count Analysismentioning

confidence: 94%

“…As a result of the work of Chayes (1954,1956), which demonstrated that areal measurements provide unbiased estimates of the relative volumes of rock constituents, point counting (or modal analysis) has become a standard technique in geology for estimating rock composition. In addition, applications of the technique have been used effectively by soil scientists to estimate constituents of soil horizons (Daniels et al 1968) and by biologists to estimate the volumes of structural units in tissue samples (Weibel and Elias 1967). The widespread acceptance of this technique in a number of disciplines has prompted some recent applications to archaeological ceramics as well (e.g., Braun 1982;Garrett 1986;Hantman and Plog 1982;Plog 1980;Rose and Fournier 1981;Rugge and Doyel 1980;Steponaitis 1983;Tankersley and Meinhart 1982).…”

Section: A Technique For the Quantitative Analysis Of Ceramic Thin Sementioning

confidence: 99%

A Quantitative Approach to the Petrographic Analysis of Ceramic Thin Sections

Stoltman

1989

Am. antiq.

137

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This paper introduces a new technique for the quantitative analysis of ceramic thin sections through petrography. The technique is a version of point counting that estimates with considerable precision the amounts of human additives (temper) and natural inclusions (silt and sand) in ceramic pastes. In concert with traditional qualitative identification of mineral inclusions, this technique expands the capacity of petrography to shed meaningful light on such topics in ceramic analysis as technology, production, trade, and classification. To demonstrate the utility of the technique it is used to reassess the taxonomic status of the type Spring Hollow Incised. The results conclusively show that Spring Hollow Incised is much more closely related to a newly defined Early Woodland ceramic assemblage in the Upper Mississippi Valley region than to the Middle Woodland Linn ware to which it originally was assigned.

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Application of the Point-Count Method to Problems of Soil Morphology

Cited by 10 publications

References 0 publications

Leaf area and growth of Chilean radiata pine plantations after thinning across a water stress gradient

Leaf area and growth of Chilean radiata pine plantations after thinning across a water stress gradient

Changes in land use/cover mapped over 80 years in the Highlands of Northern Ethiopia

A Quantitative Approach to the Petrographic Analysis of Ceramic Thin Sections

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