Field test of canopy cover estimation by hemispherical
photographs taken with a smartphone

J 2016

Field test of canopy cover estimation by hemispherical photographs taken with a smartphone

TICHÝ, Lubomír

Basic information

Original name

Field test of canopy cover estimation by hemispherical photographs taken with a smartphone

Authors

TICHÝ, Lubomír (203 Czech Republic, guarantor, belonging to the institution)

Edition

Journal of Vegetation Science, HOBOKEN, International Association for Vegetation Science, Wiley, 2016, 1100-9233

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10600 1.6 Biological sciences

Country of publisher

United States of America

Confidentiality degree

není předmětem státního či obchodního tajemství

Impact factor

Impact factor: 2.924

RIV identification code

RIV/00216224:14310/16:00088740

Organization unit

Faculty of Science

DOI

http://dx.doi.org/10.1111/jvs.12350

UT WoS

000370621500021

Keywords in English

Canopy closure; Canopy cover; Field research; Forest ecology; Gap light analysis; Smartphone application

Abstract

V originále

AimTo test the Canopy Cover (CaCo) index for forest vegetation research estimation of canopy cover from hemispherical photographs, and introduce a new Android smartphone application for use of this index. MethodsThe original and modified CaCo index were evaluated using a data set of 234 hemispherical photographs taken in 78 plots in coniferous, mixed and broad-leaved deciduous forests. The results of the CaCo analysis of these photographs were compared with expert field visual estimation of canopy cover of these plots. For each hemispherical photograph, several CaCo values were calculated based on the photograph being restricted to different degrees by artificial horizon masking. The CaCo index was also tested with respect to precision of canopy cover estimation and sensitivity to different photographic equipment, using a different set of 93 canopy photographs taken in mixed and coniferous forests. Calculation of the CaCo index was done with the newly developed GLAMA - Gap Light Analysis Mobile Application software. ResultsLinear regression showed a close relationship between the CaCo index and visually observed canopy cover data. A proposed calculation modification improved the stability of the CaCo index in cases in which no horizon masking was applied. The best fit, zero-intercept and a regression slope close to1 were found in cases in which an artificial horizon mask that extended higher than 45 degrees restricted the bottom part of the sky hemisphere. Low sensitivity of the CaCo index to type of photographic equipment used was shown. ConclusionsThe CaCo index is robust and can be used for precise canopy cover estimation, comparable to visual canopy cover estimation and unaffected by observer bias. Not only can it be used on already-captured photographs, but the index can also be employed on smartphones to rapidly capture hemispherical photographs and immediately calculate their index values. This application is freely available on the Internet and can serve as a powerful research and educational tool that can not only calculate CaCo values, but also standardize forest canopy visual estimates.

Links

GAP505/11/0732, research and development project

Name: Zobecněná řízená klasifikace v ekologii společenstev

Investor: Czech Science Foundation

Citovat

TICHÝ, Lubomír. Field test of canopy cover estimation by hemispherical photographs taken with a smartphone. Journal of Vegetation Science. HOBOKEN: International Association for Vegetation Science, Wiley, 2016, vol. 27, No 2, p. 427-435. ISSN 1100-9233. Available from: https://dx.doi.org/10.1111/jvs.12350.

@article{1374442,
   author = {Tichý, Lubomír},
   article_location = {HOBOKEN},
   article_number = {2},
   doi = {http://dx.doi.org/10.1111/jvs.12350},
   keywords = {Canopy closure; Canopy cover; Field research; Forest ecology; Gap light analysis; Smartphone application},
   language = {eng},
   issn = {1100-9233},
   journal = {Journal of Vegetation Science},
   title = {Field test of canopy cover estimation by hemispherical photographs taken with a smartphone},
   volume = {27},
   year = {2016}
}

TY  - JOUR
ID  - 1374442
AU  - Tichý, Lubomír
PY  - 2016
TI  - Field test of canopy cover estimation by hemispherical photographs taken with a smartphone
JF  - Journal of Vegetation Science
VL  - 27
IS  - 2
SP  - 427-435
EP  - 427-435
PB  - International Association for Vegetation Science, Wiley
SN  - 11009233
KW  - Canopy closure
KW  - Canopy cover
KW  - Field research
KW  - Forest ecology
KW  - Gap light analysis
KW  - Smartphone application
N2  - AimTo test the Canopy Cover (CaCo) index for forest vegetation research estimation of canopy cover from hemispherical photographs, and introduce a new Android smartphone application for use of this index. MethodsThe original and modified CaCo index were evaluated using a data set of 234 hemispherical photographs taken in 78 plots in coniferous, mixed and broad-leaved deciduous forests. The results of the CaCo analysis of these photographs were compared with expert field visual estimation of canopy cover of these plots. For each hemispherical photograph, several CaCo values were calculated based on the photograph being restricted to different degrees by artificial horizon masking. The CaCo index was also tested with respect to precision of canopy cover estimation and sensitivity to different photographic equipment, using a different set of 93 canopy photographs taken in mixed and coniferous forests. Calculation of the CaCo index was done with the newly developed GLAMA - Gap Light Analysis Mobile Application software. ResultsLinear regression showed a close relationship between the CaCo index and visually observed canopy cover data. A proposed calculation modification improved the stability of the CaCo index in cases in which no horizon masking was applied. The best fit, zero-intercept and a regression slope close to1 were found in cases in which an artificial horizon mask that extended higher than 45 degrees restricted the bottom part of the sky hemisphere. Low sensitivity of the CaCo index to type of photographic equipment used was shown. ConclusionsThe CaCo index is robust and can be used for precise canopy cover estimation, comparable to visual canopy cover estimation and unaffected by observer bias. Not only can it be used on already-captured photographs, but the index can also be employed on smartphones to rapidly capture hemispherical photographs and immediately calculate their index values. This application is freely available on the Internet and can serve as a powerful research and educational tool that can not only calculate CaCo values, but also standardize forest canopy visual estimates.
ER  -

TICHÝ, Lubomír. Field test of canopy cover estimation by hemispherical photographs taken with a smartphone. \textit{Journal of Vegetation Science}. HOBOKEN: International Association for Vegetation Science, Wiley, 2016, vol.~27, No~2, p.~427-435. ISSN~1100-9233. Available from: https://dx.doi.org/10.1111/jvs.12350.

Detailed Information on Publication Record