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Titolo:
DERIVATIONS OF STAND HEIGHTS FROM AIRBORNE LASER SCANNER DATA WITH CANOPY-BASED QUANTILE ESTIMATORS
Autore:
MAGNUSSEN S; BOUDEWYN P;
Indirizzi:
CANADIAN FORESTRY SERV,PACIFIC FORESTRY CTR,506 W BURNSIDE RD VICTORIA BC V8Z 1M5 CANADA
Titolo Testata:
Canadian journal of forest research (Print)
fascicolo: 7, volume: 28, anno: 1998,
pagine: 1016 - 1031
SICI:
0045-5067(1998)28:7<1016:DOSHFA>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
FOREST CANOPY; LEAF-AREA; GROWTH; VOLUME; ALTIMETER; PROFILES; SYSTEM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
58
Recensione:
Indirizzi per estratti:
Citazione:
S. Magnussen e P. Boudewyn, "DERIVATIONS OF STAND HEIGHTS FROM AIRBORNE LASER SCANNER DATA WITH CANOPY-BASED QUANTILE ESTIMATORS", Canadian journal of forest research (Print), 28(7), 1998, pp. 1016-1031

Abstract

The distribution of canopy heights obtained with an airborne laser scanner over a field trial with Douglas-fir (Pseudotsuga menziesii (Mirb. ) France) was a function of the vertical distribution of foliage area. Over a wide range of canopy structures, the proportion of laser pulses returned from or above a given reference height was proportional tothe fraction of leaf area above it. We hypothesized that the quantileof the laser canopy heights matching in probability the fraction of leaf area above a desired height would be an unbiased estimator of same. This was confirmed in 36 (20 x 20 m) plots and 6 older validation plots. Canopy-based quantiles of the laser canopy height data were within 6% (mean 3%) of the field estimates. Laser and field estimates were strongly correlated (r similar to 0.8), and statistical tests supported the null hypotheses of no difference in mean stand height (P > 0.3). A geometric model successfully predicted the mean difference between the laser canopy heights and the mean tree height. Our results explicate why estimation of stand heights from laser scanner data based on the maximum canopy height value in each cell of a fixed area grid has been successful in practice.

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Documento generato il 05/12/20 alle ore 19:27:21