Residual leaf area as a measure of shrub use

Leaf surface area present on black cottonwood (Populus trichocarpa) and Douglas hawthorn (Crataegus douglasi) was measured indirectly using a point frame, photographs, and a canopy analyzer. Each was compared to directly measured leaf surface area. Six black cottonwood and 3 Douglas hawthorn shrubs...

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Main Author: Reynolds, Mark P.
Other Authors: Johnson, Douglas E.
Language:en_US
Published: 2013
Subjects:
Online Access:http://hdl.handle.net/1957/36755
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spelling ndltd-ORGSU-oai-ir.library.oregonstate.edu-1957-367552013-02-13T15:32:25ZResidual leaf area as a measure of shrub useReynolds, Mark P.Black cottonwood -- UtilizationHawthorns -- UtilizationLeaf surface area present on black cottonwood (Populus trichocarpa) and Douglas hawthorn (Crataegus douglasi) was measured indirectly using a point frame, photographs, and a canopy analyzer. Each was compared to directly measured leaf surface area. Six black cottonwood and 3 Douglas hawthorn shrubs were selected in 1996 and 9 black cottonwood and 3 Douglas hawthorn shrubs in 1997. Shrubs were selected based on size and isolation. Each indirect method was applied prior to removing a portion of leaves from each shrub. Shrubs were defoliated in 3 to 7 increments and leaf surface area of each was measured. After shrubs were completely defoliated increments of measured leaf areas were added to subsequently removed leaf areas to determine the measured leaf area present on a shrub each time indirect methods were applied. Measured leaf areas were paired with indirect method values and regression equations were developed. Correlation coefficients for regressions were 0.76 for black cottonwood and 0.70 for Douglas hawthorn for the point frame, 0.91 for black cottonwood and 0.79 for Douglas hawthorn for the photographs, 0.62 for black cottonwood and 0.61 for Douglas hawthorn when shrub volume was included for the canopy analyzer. Photographs took 20 minutes to set up and take pictures followed by 1.5 hours for processing images in Idrisi and Picture Publisher. The point frame required 45 minutes to 1.5 hours field time and 5 to 10 minutes to process data. The canopy analyzer was the most rapid of the techniques requiring less than 5 minutes to secure a field measurement and enter this value into the regression equation. Canopy analyzer reliability was the lowest of the methods studied.Graduation date: 1999Johnson, Douglas E.Krueger, William C.2013-02-12T16:21:19Z2013-02-12T16:21:19Z1999-03-101999-03-10Thesis/Dissertationhttp://hdl.handle.net/1957/36755en_US
collection NDLTD
language en_US
sources NDLTD
topic Black cottonwood -- Utilization
Hawthorns -- Utilization
spellingShingle Black cottonwood -- Utilization
Hawthorns -- Utilization
Reynolds, Mark P.
Residual leaf area as a measure of shrub use
description Leaf surface area present on black cottonwood (Populus trichocarpa) and Douglas hawthorn (Crataegus douglasi) was measured indirectly using a point frame, photographs, and a canopy analyzer. Each was compared to directly measured leaf surface area. Six black cottonwood and 3 Douglas hawthorn shrubs were selected in 1996 and 9 black cottonwood and 3 Douglas hawthorn shrubs in 1997. Shrubs were selected based on size and isolation. Each indirect method was applied prior to removing a portion of leaves from each shrub. Shrubs were defoliated in 3 to 7 increments and leaf surface area of each was measured. After shrubs were completely defoliated increments of measured leaf areas were added to subsequently removed leaf areas to determine the measured leaf area present on a shrub each time indirect methods were applied. Measured leaf areas were paired with indirect method values and regression equations were developed. Correlation coefficients for regressions were 0.76 for black cottonwood and 0.70 for Douglas hawthorn for the point frame, 0.91 for black cottonwood and 0.79 for Douglas hawthorn for the photographs, 0.62 for black cottonwood and 0.61 for Douglas hawthorn when shrub volume was included for the canopy analyzer. Photographs took 20 minutes to set up and take pictures followed by 1.5 hours for processing images in Idrisi and Picture Publisher. The point frame required 45 minutes to 1.5 hours field time and 5 to 10 minutes to process data. The canopy analyzer was the most rapid of the techniques requiring less than 5 minutes to secure a field measurement and enter this value into the regression equation. Canopy analyzer reliability was the lowest of the methods studied. === Graduation date: 1999
author2 Johnson, Douglas E.
author_facet Johnson, Douglas E.
Reynolds, Mark P.
author Reynolds, Mark P.
author_sort Reynolds, Mark P.
title Residual leaf area as a measure of shrub use
title_short Residual leaf area as a measure of shrub use
title_full Residual leaf area as a measure of shrub use
title_fullStr Residual leaf area as a measure of shrub use
title_full_unstemmed Residual leaf area as a measure of shrub use
title_sort residual leaf area as a measure of shrub use
publishDate 2013
url http://hdl.handle.net/1957/36755
work_keys_str_mv AT reynoldsmarkp residualleafareaasameasureofshrubuse
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