Modeling relative error in stem basal area estimates
作者:
T. G. Gregoire,
S. M. Zedaker,
N. S. Nicholas,
期刊:
Canadian Journal of Forest Research
(NRC Available online 1990)
卷期:
Volume 20,
issue 5
页码: 496-502
ISSN:0045-5067
年代: 1990
DOI:10.1139/x90-065
出版商: NRC Research Press
数据来源: NRC
摘要:
The computed estimate of basal area was the focus of this investigation into the accuracy of tree diameter measurements. Diameter at breast height was measured on 101 trees, the breast height disc was removed from the stem, and each disc outline was then digitized to determine its actual area. Actual areas were compared with the basal areas computed with the field measurements of diameter by expressing the deviations as a proportion of the actual areas. These relative errors averaged 3.1% when basal area was computed with a taped diameter at breast height, and they averaged −2.5% when the mean of two calipered, perpendicular diameter at breast height measurements were used. Noncircularity accounted for about 2.6% of the bias, on average, in basal areas from taped diameters. Root mean square error of relative basal area errors ranged from 7.3 to 7.9% among these methods. The difference between basal areas computed with a taped diameter at breast height and with calipered diameter at breast height was computed and expressed as a proportion of the actual basal area. On average, a difference of 5% was observed. Interval estimates for these differences are presented.
点击下载:
PDF
(156KB)
返 回