Estimation of foliage denseness and foliage angle by inclined point quadrats

Wilson, J. Warren

doi:10.1071/bt9630095

Cited by 245 publications

(70 citation statements)

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“…Wilson 1960;Dufrêne and Bréda 1995), but offer only a low resolution as the number of contacts within the total number of shots to the canopy is a spatial average (Levy and Madden 1933;Goodall 1952) and is useful on the canopy level only, even though heights at which contacts occur can also be protocolled (Wilson 1963).…”

Section: Accuracy and Resolutionmentioning

confidence: 99%

Review of ground-based methods to measure the distribution of biomass in forest canopies

Seidel

Fleck

Leuschner

et al. 2011

Annals of Forest Science

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& Context Ecological research and an effective forest management need accurate information on the structure of the forest canopy to understand the biochemical, physiological and biogeochemical processes within a forest. & Research question This paper reviews the currently available instruments for measuring the distribution of biomass within forest canopies. We compare the most well-established approaches and present the different measurable parameters. A special focus lies on the resolution of the obtained data. & Results It was found that only 3D laser scanners offer data with the resolution required by ecologists, private landholders, the forest industry and the public to detect trends in tree growth patterns and canopy interactions in all three spatial dimensions. But data validation, data analysis and parameter extraction are still under development, and the price of the instrument is quite high. & Conclusion Research should focus on the parameter extraction from terrestrial laser scanner data as this could allow the calculation of functional attributes for different sections of a canopy on a high spatial resolution. It could also help ecologists characterize the structure of forest stands in a quick and precise way.

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Section: Accuracy and Resolutionmentioning

confidence: 99%

Review of ground-based methods to measure the distribution of biomass in forest canopies

Seidel

Fleck

Leuschner

et al. 2011

Annals of Forest Science

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“…In the first method, the vertical distribution of material within the canopy was measured by means of a foliage height profile (MacArthur and Horn 1969) using the camera point-quadrat method developed by Aber (1979a). This point-quadrat sampling method was first described by Warren Wilson (1960Wilson ( , 1963 who utilized a series of vertical transects from the top to the bottom of the canopy. Along each vertical transect the height of each intersecting leaf is recorded.…”

Section: Field Based Measures Of Canopy Structurementioning

confidence: 99%

“…Less commonly used field-based methods to determine the distribution of both vertical and horizontal canopy elements include: the point-quadrat method (Warren-Wilson 1960, 1963, Aber, 1979a, which measures the interception of canopy elements in a series of vertical transects throughout the stand, and inventory-based foliar profiles estimated from measurements of crown dimensions and assuming a uniform foliage density within crown volumes (Walter and Hopkins 1990).…”

Section: Introductionmentioning

confidence: 99%

Estimating canopy structure of Douglas-fir forest stands from discrete-return LiDAR

Coops

Hilker

Wulder

et al. 2007

Trees

312

223

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“…The vertical distribution of plant tissue within the sward canopy was measured monthly using an inclined point quadrat (Warren Wilson 1963) set at 32.5° to the horizontal. At least 100 contacts were recorded in each plot every month.…”

Section: Sward Measurementsmentioning

confidence: 99%

Herbage intake, ingestive behaviour and diet selection, and effects of condensed tannins upon body and wool growth in lambs grazingLolium perenneandHolcus lanatusswards in summer

Montossi

Hodgson

1997

New Zealand Journal of Agricultural Research

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A comparative study was undertaken in New Zealand to investigate the effects of low concentrations of condensed tannins (CT) on diet selection, herbage intake, and performance in lambs grazing on four 0.2 ha paddocks each of perennial ryegrass (Lolium perenne) or Yorkshire fog (Holcus lanatus) with less than 10% white clover (Trifolium repens), continuously grazed at a constant height of approximately 6 cm from December 1992 to March 1993. The effects of CT on rumen metabolism and animal production were assessed by twice daily oral administration of polyethylene glycol (PEG; MW 4000) to half of the lambs on each sward.Bite weight was greater for Yorkshire fog swards than for ryegrass swards during January (111 vs 85 ± 5 mg OM/bite, P < 0.01), but not in December. In both December and January, grazing, A96080Received 14 November 1996; accepted 11 August 1997 ruminating, and idling times were similar between swards, while in January, the rate of biting in ryegrass swards was higher than in Yorkshire fog swards (64 vs 61 ± 1 bites/min, P < 0.05). The organic matter digestibility (OMD) of the herbage selected was higher in ryegrass swards in December (81 vs 78 ± 0.04 %, P < 0.01), but not in January (80 vs 79 ± 0.05 %). The herbage intake achieved by lambs grazing ryegrass swards was 23% higher than that achieved on Yorkshire fog swards in December (990 vs 800 ± 36 g OM/lamb/day, P < 0.05) whereas, in January, herbage intakes did not differ significantly. Lambs grazing on ryegrass swards had higher clean wool growth (1147 vs 1085 ± 15 ng/cm 2 per day, P < 0.10) and carcass weight (17.5 vs 16.3 ± 0.22 kg, P < 0.05) than lambs grazing on Yorkshire fog swards. The stocking rate maintained on ryegrass plots was 25% greater than on Yorkshire fog plots.Low concentrations of CT were recorded in the diets of sheep on ryegrass and Yorkshire fog swards (< 0.2% on a DM basis). The low levels of CT had no significant effects on diet selection, herbage intake, grazing behaviour patterns, or lamb performance. However, the lambs grazing on Yorkshire fog swards showed small and nonpersistent responses to CT in terms of wool growth and liveweight gain. The results of this study indicate that: (i) under high fertility conditions and intensive management, perennial ryegrass/white clover swards appear to have higher feeding value than Yorkshire fog/white clover swards for lamb production and (ii) the low CT concentrations (< 0.2% in the DM) observed in both swards did not influence lamb performance significantly.

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Estimation of foliage denseness and foliage angle by inclined point quadrats

Cited by 245 publications

References 0 publications

Review of ground-based methods to measure the distribution of biomass in forest canopies

Review of ground-based methods to measure the distribution of biomass in forest canopies

Estimating canopy structure of Douglas-fir forest stands from discrete-return LiDAR

Herbage intake, ingestive behaviour and diet selection, and effects of condensed tannins upon body and wool growth in lambs grazingLolium perenneandHolcus lanatusswards in summer

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