Cover-Weight Relationships

Payne, Gene F.

doi:10.2307/3896504

Cited by 19 publications

(16 citation statements)

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“…Individual lifeform annual productions were determined by multiplying average percentage cover values by lifeform (Payne 1974;Olson and Martin 1981) for each stand, treatment, sampling period, and year combination by the total understory vegetation annual production amount. See VanderSchaaf et al (2000) for a description of percentage cover methodology and results.…”

Section: Vegetation Measurementsmentioning

confidence: 99%

Estimating understory vegetation response to multi-nutrient fertilization in Douglas-fir and ponderosa pine stands

VanderSchaaf

2008

Journal of Forest Research

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Models were developed to predict understory vegetation response to multi-nutrient fertilization at six conifer-forested stands in the inland Northwest United States. Equations are presented to estimate how fertilization as well as other factors impacting understory production in the inland Northwest change total understory vegetation production and the production of three individual lifeforms (shrubs, forbs, and grasses and grasslikes). Overstory stand density was found to have the greatest impact on understory production, and regardless of factors such as fertilization or precipitation, large stand densities will limit understory production. At lower stand densities, multi-nutrient fertilization as well as greater amounts of precipitation will increase understory production. These factors were also found to be synergistic; thus, greater amounts of precipitation increase the effects of multi-nutrient fertilization on understory production. For sites of the same stand density, Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] was shown to have a greater negative impact on understory production than ponderosa pine (Pinus ponderosa Dougl. ex Laws.). The models predict that multi-nutrient fertilization of ponderosa pine stands will produce increases in understory production across a broader range of stand densities.

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Section: Vegetation Measurementsmentioning

confidence: 99%

Estimating understory vegetation response to multi-nutrient fertilization in Douglas-fir and ponderosa pine stands

VanderSchaaf

2008

Journal of Forest Research

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“…Relative percent species composition by weight used in the range condition analysis method favors plants that produce more biomass, while the Ecodata system emphasizes canopy cover. Payne (1974) found that the average correlation of cover and weight was 0.62 for all grass species and provided evidence that correlations between weight and cover could vary from R = 0.98 to R = 0.14 depending on the individual plant species. Therefore, differences between ecological status scores and range condition scores could be due to variable correlations between plant weight and canopy cover.…”

Section: Discussionmentioning

confidence: 78%

Journal of Range Management, Volume 53, Number 2 (March 2000)

2000

REM

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POSTMASTER: Return entire journal with address change -R E T U R N P O S TA G EG U A R A N- T h e Journal of Range Management is a publication of the Society for RangeManagement. It serves as a forum for the presentation and discussion of facts, ideas, and philosophies pertaining to the study, management, and use of rangelands and their several resources. Accordingly, all material published herein is signed and reflects the individual views of the authors and is not necessarily an official position of the Society. Manuscripts from anyone-nonmembers as well as members-are welcome and will be given every consideration by the editors. Editorial comments by an individual are also welcome and, subject to acceptance by the editor, will be published as a "Viewpoint." In AbstractWe compared the herbage standing crop on 31 farms along a rainfall gradient in Namibia (southwestern Africa) in 1997 with the results attained for the same gradient by Walter (1939). We found that the slope for the regression of herbage yield on mean annual rainfall in 1997 was 5.93, i.e. 5.93 kg herbage was produced per hectare for every 1 mm increase in rainfall along the gradient. This regression slope is considerably lower than that in Walter's (1939) study (slope = 10.34). Thus, current grassland productivity per unit of rainfall in Namibia is about half that of 50 years ago. There is no evidence of a change in annual rainfall over this period, nor is there any evidence that either short-term (current) or longer-term (11 years) stocking densities affect current herbage yield. We conclude that, while desertification has taken place, grazing over the last decade has not been the cause of this reduced productivity.Key Words: Africa, rangelands, historical records, grazing, rainfall There is widespread concern over desertification (i.e. a longterm decline in productivity) of the semi-arid grasslands of the world (Schlesinger et al. 1990, 1996, Hall and Scurlock 1991, Strohbach 1992, Parton et al. 1995. However, it is often difficult to unequivocally determine whether desertification has occurred, because different types of information (e.g. on soil quality, carbon isotopes, vegetation quality and quantity) may give conflicting results (Hoffman et al. 1995, Parton et al. 1995, Parsons et al. 1997. Also, logistical problems such as variability in annual rainfall cause great natural fluctuations in herbage growth, making it difficult to differentiate pattern in declining productivity from noise caused by random or event-driven fluctuations (Hoffman and Cowling 1990, Sullivan 1996, Hoffman 1997, Ward et al. 1998, Ward et al. 1999. Long-term cycles in rainfall can further exacerbate this problem. For example, Hoffman and Cowling (1990) and Hoffman (1997) have shown that Acocks ' (1953) claim that desertification was rampant in the semi-arid Karoo region of South Africa was probably caused by the long dry period in the 1950's. When one compares photographs of the vegetation taken in 1925 by I.B. Pole Evans with photographs taken at the same ...

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“…In mountain ranges of southwestern Montana, Payne (1974) found a significant correlation greater than 0.90 between canopy cover and herbage weight for 16 species. Only six species showed a significant correlation coefficient (r) less than 0.7.…”

Section: Covermentioning

confidence: 82%

Rangeland vegetation productivity and biomass

Pieper¹

1988

Vegetation Science Applications for Rangeland Analysis and Management

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Herbage weight or biomass is an important characteristic for range vegetation since it supports directly or indirectly all consumer groups. Plant biomass is also important as a measure of dominance in plant communities. Many methods have been devised to estimate plant biomass, but all have some limitations. Estimation techniques, either by plot or plant, often involve a double sampling procedure to improve on the estimates. Direct harvesting is a destructive sampling procedure which is often used when biomass is the response measured in research studies. Precipitation has been used as an independent variable to predict end-of-season biomass. However, considerable data are necessary to develop reliable relationships. Capacitance meters, biomass meters, and p-attenuation techniques have promise for specific situations, but have not received widespread support among range researchers and ecologists. All these techniques require considerable calibration before they can be used for specific situations. Plant biomass data are useful for establishing dominance of individual species, estimating livestock stocking rates, and determining range condition. IntroductionMeasurement of plant biomass or standing crop has been of interest to range workers for some time because herbivores depend directly upon plant biomass for their food. Interest in production ecology is of more recent emphasis by plant ecologists, particularly during the International Biological Program Studies during the 1970's (Milner and Hughes 1968). These studies illustrate the importance of plant biomass as an indicator of general ecological importance of individual plants and communities.

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Cover-Weight Relationships

Cited by 19 publications

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Estimating understory vegetation response to multi-nutrient fertilization in Douglas-fir and ponderosa pine stands

Estimating understory vegetation response to multi-nutrient fertilization in Douglas-fir and ponderosa pine stands

Journal of Range Management, Volume 53, Number 2 (March 2000)

Rangeland vegetation productivity and biomass

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