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

Základní údaje

Originální název

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

Autoři

TICHÝ, Lubomír (203 Česká republika, garant, domácí)

Vydání

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

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10600 1.6 Biological sciences

Stát vydavatele

Spojené státy

Utajení

není předmětem státního či obchodního tajemství

Impakt faktor

Impact factor: 2.924

Kód RIV

RIV/00216224:14310/16:00088740

Organizační jednotka

Přírodovědecká fakulta

DOI

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

UT WoS

000370621500021

Klíčová slova anglicky

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

Štítky

AKR, rivok

Změněno: 20. 3. 2018 13:11, Mgr. Lucie Jarošová, DiS.

Anotace

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.

Návaznosti

GAP505/11/0732, projekt VaV

Název: Zobecněná řízená klasifikace v ekologii společenstev

Investor: Grantová agentura ČR, Generalized supervised classification in community ecology

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, roč. 27, č. 2, s. 427-435. ISSN 1100-9233. Dostupné z: 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, roč.~27, č.~2, s.~427-435. ISSN~1100-9233. Dostupné z: https://dx.doi.org/10.1111/jvs.12350.

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