Is the spherical leaf inclination angle distribution a valid assumption for temperate and boreal broadleaf tree species?

Jan Pisek, Oliver Sonnentag, Andrew D. Richardson, Matti Mõttus

Research output: Contribution to journalArticleScientificpeer-review

63 Citations (Scopus)

Abstract

Angular distribution of leaves is an important parameter determining the transmission and reflection of radiation by vegetation canopies. When inverting canopy transmittance measurements for estimating the leaf area index or canopy clumping, incorrect assumptions on leaf angles may lead to considerable errors. To address this issue, we measured an extensive data set of leaf angle distributions for 58 deciduous broadleaf tree species commonly found in temperate and boreal ecoclimatic regions. Additionally, a small subset of species was sampled several times during the growing season. We found that reliable estimates of leaf angle distributions at the level of a whole tree can be obtained by measuring the leaf inclination angles of 75 leaves distributed across the vertical tree profile using a simple technique based on digital photography. According to our measurements, the common assumption of a spherical leaf angle distribution often used when no measurement data is available is not a valid assumption for most of the studied tree species. Our multitemporal measurements indicated no seasonality of leaf inclination angles of the selected tree species, except directly after budburst. Finally, using a gap fraction model, we illustrate the influence of different leaf angle distributions on the clumping factor and leaf area index. We advocate the use of species-specific leaf angle distributions from actual leaf inclination measurements. However, a planophile or a plagiophile leaf angle distribution appears to be a more appropriate assumption than a spherical one for modeling radiation transmission through temperate and boreal broadleaf stands when no leaf inclination angle measurements are available.

Original languageEnglish
Pages (from-to)186-194
Number of pages9
JournalAgricultural and Forest Meteorology
Volume169
DOIs
Publication statusPublished - 15 Feb 2013
MoE publication typeA1 Journal article-refereed

Fingerprint

leaf angle
canopy
leaf area index
distribution
leaves
transmittance
digital images
budburst
deciduous tree
photography
growing season
seasonality

Keywords

  • Digital photography
  • G-function
  • Gap fraction
  • Leaf inclination angle

Cite this

@article{157558f714974aada0fbbfb0b159f73b,
title = "Is the spherical leaf inclination angle distribution a valid assumption for temperate and boreal broadleaf tree species?",
abstract = "Angular distribution of leaves is an important parameter determining the transmission and reflection of radiation by vegetation canopies. When inverting canopy transmittance measurements for estimating the leaf area index or canopy clumping, incorrect assumptions on leaf angles may lead to considerable errors. To address this issue, we measured an extensive data set of leaf angle distributions for 58 deciduous broadleaf tree species commonly found in temperate and boreal ecoclimatic regions. Additionally, a small subset of species was sampled several times during the growing season. We found that reliable estimates of leaf angle distributions at the level of a whole tree can be obtained by measuring the leaf inclination angles of 75 leaves distributed across the vertical tree profile using a simple technique based on digital photography. According to our measurements, the common assumption of a spherical leaf angle distribution often used when no measurement data is available is not a valid assumption for most of the studied tree species. Our multitemporal measurements indicated no seasonality of leaf inclination angles of the selected tree species, except directly after budburst. Finally, using a gap fraction model, we illustrate the influence of different leaf angle distributions on the clumping factor and leaf area index. We advocate the use of species-specific leaf angle distributions from actual leaf inclination measurements. However, a planophile or a plagiophile leaf angle distribution appears to be a more appropriate assumption than a spherical one for modeling radiation transmission through temperate and boreal broadleaf stands when no leaf inclination angle measurements are available.",
keywords = "Digital photography, G-function, Gap fraction, Leaf inclination angle",
author = "Jan Pisek and Oliver Sonnentag and Richardson, {Andrew D.} and Matti M{\~o}ttus",
year = "2013",
month = "2",
day = "15",
doi = "10.1016/j.agrformet.2012.10.011",
language = "English",
volume = "169",
pages = "186--194",
journal = "Agricultural and Forest Meteorology",
issn = "0168-1923",
publisher = "Elsevier",

}

Is the spherical leaf inclination angle distribution a valid assumption for temperate and boreal broadleaf tree species? / Pisek, Jan; Sonnentag, Oliver; Richardson, Andrew D.; Mõttus, Matti.

In: Agricultural and Forest Meteorology, Vol. 169, 15.02.2013, p. 186-194.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Is the spherical leaf inclination angle distribution a valid assumption for temperate and boreal broadleaf tree species?

AU - Pisek, Jan

AU - Sonnentag, Oliver

AU - Richardson, Andrew D.

AU - Mõttus, Matti

PY - 2013/2/15

Y1 - 2013/2/15

N2 - Angular distribution of leaves is an important parameter determining the transmission and reflection of radiation by vegetation canopies. When inverting canopy transmittance measurements for estimating the leaf area index or canopy clumping, incorrect assumptions on leaf angles may lead to considerable errors. To address this issue, we measured an extensive data set of leaf angle distributions for 58 deciduous broadleaf tree species commonly found in temperate and boreal ecoclimatic regions. Additionally, a small subset of species was sampled several times during the growing season. We found that reliable estimates of leaf angle distributions at the level of a whole tree can be obtained by measuring the leaf inclination angles of 75 leaves distributed across the vertical tree profile using a simple technique based on digital photography. According to our measurements, the common assumption of a spherical leaf angle distribution often used when no measurement data is available is not a valid assumption for most of the studied tree species. Our multitemporal measurements indicated no seasonality of leaf inclination angles of the selected tree species, except directly after budburst. Finally, using a gap fraction model, we illustrate the influence of different leaf angle distributions on the clumping factor and leaf area index. We advocate the use of species-specific leaf angle distributions from actual leaf inclination measurements. However, a planophile or a plagiophile leaf angle distribution appears to be a more appropriate assumption than a spherical one for modeling radiation transmission through temperate and boreal broadleaf stands when no leaf inclination angle measurements are available.

AB - Angular distribution of leaves is an important parameter determining the transmission and reflection of radiation by vegetation canopies. When inverting canopy transmittance measurements for estimating the leaf area index or canopy clumping, incorrect assumptions on leaf angles may lead to considerable errors. To address this issue, we measured an extensive data set of leaf angle distributions for 58 deciduous broadleaf tree species commonly found in temperate and boreal ecoclimatic regions. Additionally, a small subset of species was sampled several times during the growing season. We found that reliable estimates of leaf angle distributions at the level of a whole tree can be obtained by measuring the leaf inclination angles of 75 leaves distributed across the vertical tree profile using a simple technique based on digital photography. According to our measurements, the common assumption of a spherical leaf angle distribution often used when no measurement data is available is not a valid assumption for most of the studied tree species. Our multitemporal measurements indicated no seasonality of leaf inclination angles of the selected tree species, except directly after budburst. Finally, using a gap fraction model, we illustrate the influence of different leaf angle distributions on the clumping factor and leaf area index. We advocate the use of species-specific leaf angle distributions from actual leaf inclination measurements. However, a planophile or a plagiophile leaf angle distribution appears to be a more appropriate assumption than a spherical one for modeling radiation transmission through temperate and boreal broadleaf stands when no leaf inclination angle measurements are available.

KW - Digital photography

KW - G-function

KW - Gap fraction

KW - Leaf inclination angle

UR - http://www.scopus.com/inward/record.url?scp=84869885765&partnerID=8YFLogxK

U2 - 10.1016/j.agrformet.2012.10.011

DO - 10.1016/j.agrformet.2012.10.011

M3 - Article

AN - SCOPUS:84869885765

VL - 169

SP - 186

EP - 194

JO - Agricultural and Forest Meteorology

JF - Agricultural and Forest Meteorology

SN - 0168-1923

ER -