Seasonal reflectance dynamics of common understory types in a northern European boreal forest

Miina Rautiainen, Matti Mõttus, Janne Heiskanen, Anu Akujärvi, Titta Majasalmi, Pauline Stenberg

Research output: Contribution to journalArticleScientificpeer-review

52 Citations (Scopus)

Abstract

The influence of the seasonal cycle of boreal forest understory has been noticed in global remote sensing of vegetation, especially in remote sensing of biophysical properties (e.g. leaf area index) of the tree-layer in a forest. A general problem in the validation of operationally produced global biophysical vegetation products is the lack of ground reference data on the seasonal variability of different land surface types. Currently, little is known about the spectral properties of the understory layers of boreal forests, and even less is known about the seasonal dynamics of the spectra. In this paper, we report seasonal trajectories of understory reflectance spectra measured in a European boreal forest. Four study sites representing different forest fertility site types were selected from central Finland. The understory composition was recorded and its spectra measured with an ASD FieldSpec Hand-Held UV/VNIR Spectroradiometer ten times during the growing period (from May to September) in 2010. Our results show that the spectral differences between and within understory types are the largest at the peak of the growing season in early July whereas in the beginning and end of the growing season (i.e. early May and late September, respectively) the differences between the understory types are marginal. In general, the fertile sites had the brightest NIR spectra throughout the growing season whereas infertile types appeared darker in NIR. Our results also indicated that a mismatch in the seasonal development of understory and tree layers does not occur in boreal forests: the understory and tree layer vegetation develop at a similar pace in the spring (i.e. there are no or only few spring ephemerals present), and the forests with the strongest seasonal dynamics in tree canopy structure (LAI) have also the strongest dynamics in understory spectra.

Original languageEnglish
Pages (from-to)3020-3028
Number of pages9
JournalRemote Sensing of Environment
Volume115
Issue number12
DOIs
Publication statusPublished - 15 Dec 2011
MoE publication typeA1 Journal article-refereed

Fingerprint

boreal forests
boreal forest
understory
reflectance
Remote sensing
growing season
Trajectories
leaf area index
vegetation
remote sensing
Chemical analysis
spectroradiometers
seasonal development
forest canopy
forest trees
trajectories
Finland
fertility
land surface
hands

Keywords

  • Boreal
  • Reflectance
  • Spectroscopy
  • Understory

Cite this

Rautiainen, Miina ; Mõttus, Matti ; Heiskanen, Janne ; Akujärvi, Anu ; Majasalmi, Titta ; Stenberg, Pauline. / Seasonal reflectance dynamics of common understory types in a northern European boreal forest. In: Remote Sensing of Environment. 2011 ; Vol. 115, No. 12. pp. 3020-3028.
@article{55ea7c28e4fe45b797e9a72ede38de82,
title = "Seasonal reflectance dynamics of common understory types in a northern European boreal forest",
abstract = "The influence of the seasonal cycle of boreal forest understory has been noticed in global remote sensing of vegetation, especially in remote sensing of biophysical properties (e.g. leaf area index) of the tree-layer in a forest. A general problem in the validation of operationally produced global biophysical vegetation products is the lack of ground reference data on the seasonal variability of different land surface types. Currently, little is known about the spectral properties of the understory layers of boreal forests, and even less is known about the seasonal dynamics of the spectra. In this paper, we report seasonal trajectories of understory reflectance spectra measured in a European boreal forest. Four study sites representing different forest fertility site types were selected from central Finland. The understory composition was recorded and its spectra measured with an ASD FieldSpec Hand-Held UV/VNIR Spectroradiometer ten times during the growing period (from May to September) in 2010. Our results show that the spectral differences between and within understory types are the largest at the peak of the growing season in early July whereas in the beginning and end of the growing season (i.e. early May and late September, respectively) the differences between the understory types are marginal. In general, the fertile sites had the brightest NIR spectra throughout the growing season whereas infertile types appeared darker in NIR. Our results also indicated that a mismatch in the seasonal development of understory and tree layers does not occur in boreal forests: the understory and tree layer vegetation develop at a similar pace in the spring (i.e. there are no or only few spring ephemerals present), and the forests with the strongest seasonal dynamics in tree canopy structure (LAI) have also the strongest dynamics in understory spectra.",
keywords = "Boreal, Reflectance, Spectroscopy, Understory",
author = "Miina Rautiainen and Matti M{\~o}ttus and Janne Heiskanen and Anu Akuj{\"a}rvi and Titta Majasalmi and Pauline Stenberg",
year = "2011",
month = "12",
day = "15",
doi = "10.1016/j.rse.2011.06.005",
language = "English",
volume = "115",
pages = "3020--3028",
journal = "Remote Sensing of Environment",
issn = "0034-4257",
publisher = "Elsevier",
number = "12",

}

Seasonal reflectance dynamics of common understory types in a northern European boreal forest. / Rautiainen, Miina; Mõttus, Matti; Heiskanen, Janne; Akujärvi, Anu; Majasalmi, Titta; Stenberg, Pauline.

In: Remote Sensing of Environment, Vol. 115, No. 12, 15.12.2011, p. 3020-3028.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Seasonal reflectance dynamics of common understory types in a northern European boreal forest

AU - Rautiainen, Miina

AU - Mõttus, Matti

AU - Heiskanen, Janne

AU - Akujärvi, Anu

AU - Majasalmi, Titta

AU - Stenberg, Pauline

PY - 2011/12/15

Y1 - 2011/12/15

N2 - The influence of the seasonal cycle of boreal forest understory has been noticed in global remote sensing of vegetation, especially in remote sensing of biophysical properties (e.g. leaf area index) of the tree-layer in a forest. A general problem in the validation of operationally produced global biophysical vegetation products is the lack of ground reference data on the seasonal variability of different land surface types. Currently, little is known about the spectral properties of the understory layers of boreal forests, and even less is known about the seasonal dynamics of the spectra. In this paper, we report seasonal trajectories of understory reflectance spectra measured in a European boreal forest. Four study sites representing different forest fertility site types were selected from central Finland. The understory composition was recorded and its spectra measured with an ASD FieldSpec Hand-Held UV/VNIR Spectroradiometer ten times during the growing period (from May to September) in 2010. Our results show that the spectral differences between and within understory types are the largest at the peak of the growing season in early July whereas in the beginning and end of the growing season (i.e. early May and late September, respectively) the differences between the understory types are marginal. In general, the fertile sites had the brightest NIR spectra throughout the growing season whereas infertile types appeared darker in NIR. Our results also indicated that a mismatch in the seasonal development of understory and tree layers does not occur in boreal forests: the understory and tree layer vegetation develop at a similar pace in the spring (i.e. there are no or only few spring ephemerals present), and the forests with the strongest seasonal dynamics in tree canopy structure (LAI) have also the strongest dynamics in understory spectra.

AB - The influence of the seasonal cycle of boreal forest understory has been noticed in global remote sensing of vegetation, especially in remote sensing of biophysical properties (e.g. leaf area index) of the tree-layer in a forest. A general problem in the validation of operationally produced global biophysical vegetation products is the lack of ground reference data on the seasonal variability of different land surface types. Currently, little is known about the spectral properties of the understory layers of boreal forests, and even less is known about the seasonal dynamics of the spectra. In this paper, we report seasonal trajectories of understory reflectance spectra measured in a European boreal forest. Four study sites representing different forest fertility site types were selected from central Finland. The understory composition was recorded and its spectra measured with an ASD FieldSpec Hand-Held UV/VNIR Spectroradiometer ten times during the growing period (from May to September) in 2010. Our results show that the spectral differences between and within understory types are the largest at the peak of the growing season in early July whereas in the beginning and end of the growing season (i.e. early May and late September, respectively) the differences between the understory types are marginal. In general, the fertile sites had the brightest NIR spectra throughout the growing season whereas infertile types appeared darker in NIR. Our results also indicated that a mismatch in the seasonal development of understory and tree layers does not occur in boreal forests: the understory and tree layer vegetation develop at a similar pace in the spring (i.e. there are no or only few spring ephemerals present), and the forests with the strongest seasonal dynamics in tree canopy structure (LAI) have also the strongest dynamics in understory spectra.

KW - Boreal

KW - Reflectance

KW - Spectroscopy

KW - Understory

UR - http://www.scopus.com/inward/record.url?scp=81355147582&partnerID=8YFLogxK

U2 - 10.1016/j.rse.2011.06.005

DO - 10.1016/j.rse.2011.06.005

M3 - Article

VL - 115

SP - 3020

EP - 3028

JO - Remote Sensing of Environment

JF - Remote Sensing of Environment

SN - 0034-4257

IS - 12

ER -