Assessing Phenological Shifts of Deciduous Forests in Turkey under Climate Change: An Assessment for <i>Fagus orientalis</i> with Daily MODIS Data for 19 Years

Understanding how natural ecosystems are and will be responding to climate change is one of the primary goals of ecological research. Plant phenology is accepted as one of the most sensitive bioindicators of climate change due to its strong interactions with climate dynamics, and a vast number of st...

Full description

Bibliographic Details
Main Authors: Tuğçe Şenel, Oğuzhan Kanmaz, Filiz Bektas Balcik, Meral Avcı, H. Nüzhet Dalfes
Format: Article
Language:English
Published: MDPI AG 2023-02-01
Series:Forests
Subjects:
Online Access:https://www.mdpi.com/1999-4907/14/2/413
_version_ 1797620991561564160
author Tuğçe Şenel
Oğuzhan Kanmaz
Filiz Bektas Balcik
Meral Avcı
H. Nüzhet Dalfes
author_facet Tuğçe Şenel
Oğuzhan Kanmaz
Filiz Bektas Balcik
Meral Avcı
H. Nüzhet Dalfes
author_sort Tuğçe Şenel
collection DOAJ
description Understanding how natural ecosystems are and will be responding to climate change is one of the primary goals of ecological research. Plant phenology is accepted as one of the most sensitive bioindicators of climate change due to its strong interactions with climate dynamics, and a vast number of studies from all around the world present evidence considering phenological shifts as a response to climatic changes. Land surface phenology (LSP) is also a valuable tool in the absence of observational phenology data for monitoring the aforementioned shift responses. Our aim was to investigate the phenological shifts of <i>Fagus orientalis</i> forests in Turkey by means of daily MODIS surface reflectance data (MOD09GA) for the period between 2002 and 2020. The normalized difference vegetation index (NDVI) was calculated for the entire Turkey extent. This extent was then masked for <i>F. orientalis</i>. These “<i>Fagus</i> pixels” were then filtered by a minimum of 80% spatial and an annual 20% temporal coverage. A combination of two methods was applied to the time series for smoothing and reconstruction and the start of season (SOS), end of season, and length of season parameters were extracted. Trends in these parameters over the 19-year period were analyzed. The results were in concert with the commonly reported earlier SOS pattern, by a Sen’s slope of −0.8 days year<sup>−1</sup>. Lastly, the relationships between SOS and mean, maximum and minimum temperature, growing degree days (GDD), and chilling hours (CH) were investigated. Results showed that the most significant correlations were found between the mean SOS trend and accumulated CH and accumulated GDD with a base temperature of 2 °C, both for the February–March interval. The immediate need for a phenological observation network in Turkey and its region is discussed.
first_indexed 2024-03-11T08:49:24Z
format Article
id doaj.art-f5ea97c399c4412f9d667fb42b8a9e4a
institution Directory Open Access Journal
issn 1999-4907
language English
last_indexed 2024-03-11T08:49:24Z
publishDate 2023-02-01
publisher MDPI AG
record_format Article
series Forests
spelling doaj.art-f5ea97c399c4412f9d667fb42b8a9e4a2023-11-16T20:35:37ZengMDPI AGForests1999-49072023-02-0114241310.3390/f14020413Assessing Phenological Shifts of Deciduous Forests in Turkey under Climate Change: An Assessment for <i>Fagus orientalis</i> with Daily MODIS Data for 19 YearsTuğçe Şenel0Oğuzhan Kanmaz1Filiz Bektas Balcik2Meral Avcı3H. Nüzhet Dalfes4Department of Climate and Marine Sciences, Eurasia Institute of Earth Sciences, Istanbul Technical University, Maslak, Istanbul 34469, TurkeyDepartment of Climate and Marine Sciences, Eurasia Institute of Earth Sciences, Istanbul Technical University, Maslak, Istanbul 34469, TurkeyDepartment of Geomatics Engineering, Faculty of Civil Engineering, Istanbul Technical University, Maslak, Istanbul 34469, TurkeyDepartment of Geography, Faculty of Letters, Istanbul University, Istanbul 34459, TurkeyDepartment of Climate and Marine Sciences, Eurasia Institute of Earth Sciences, Istanbul Technical University, Maslak, Istanbul 34469, TurkeyUnderstanding how natural ecosystems are and will be responding to climate change is one of the primary goals of ecological research. Plant phenology is accepted as one of the most sensitive bioindicators of climate change due to its strong interactions with climate dynamics, and a vast number of studies from all around the world present evidence considering phenological shifts as a response to climatic changes. Land surface phenology (LSP) is also a valuable tool in the absence of observational phenology data for monitoring the aforementioned shift responses. Our aim was to investigate the phenological shifts of <i>Fagus orientalis</i> forests in Turkey by means of daily MODIS surface reflectance data (MOD09GA) for the period between 2002 and 2020. The normalized difference vegetation index (NDVI) was calculated for the entire Turkey extent. This extent was then masked for <i>F. orientalis</i>. These “<i>Fagus</i> pixels” were then filtered by a minimum of 80% spatial and an annual 20% temporal coverage. A combination of two methods was applied to the time series for smoothing and reconstruction and the start of season (SOS), end of season, and length of season parameters were extracted. Trends in these parameters over the 19-year period were analyzed. The results were in concert with the commonly reported earlier SOS pattern, by a Sen’s slope of −0.8 days year<sup>−1</sup>. Lastly, the relationships between SOS and mean, maximum and minimum temperature, growing degree days (GDD), and chilling hours (CH) were investigated. Results showed that the most significant correlations were found between the mean SOS trend and accumulated CH and accumulated GDD with a base temperature of 2 °C, both for the February–March interval. The immediate need for a phenological observation network in Turkey and its region is discussed.https://www.mdpi.com/1999-4907/14/2/413MODISland surface phenologyNDVIphenological shift<i>Fagus orientalis</i>Turkey
spellingShingle Tuğçe Şenel
Oğuzhan Kanmaz
Filiz Bektas Balcik
Meral Avcı
H. Nüzhet Dalfes
Assessing Phenological Shifts of Deciduous Forests in Turkey under Climate Change: An Assessment for <i>Fagus orientalis</i> with Daily MODIS Data for 19 Years
Forests
MODIS
land surface phenology
NDVI
phenological shift
<i>Fagus orientalis</i>
Turkey
title Assessing Phenological Shifts of Deciduous Forests in Turkey under Climate Change: An Assessment for <i>Fagus orientalis</i> with Daily MODIS Data for 19 Years
title_full Assessing Phenological Shifts of Deciduous Forests in Turkey under Climate Change: An Assessment for <i>Fagus orientalis</i> with Daily MODIS Data for 19 Years
title_fullStr Assessing Phenological Shifts of Deciduous Forests in Turkey under Climate Change: An Assessment for <i>Fagus orientalis</i> with Daily MODIS Data for 19 Years
title_full_unstemmed Assessing Phenological Shifts of Deciduous Forests in Turkey under Climate Change: An Assessment for <i>Fagus orientalis</i> with Daily MODIS Data for 19 Years
title_short Assessing Phenological Shifts of Deciduous Forests in Turkey under Climate Change: An Assessment for <i>Fagus orientalis</i> with Daily MODIS Data for 19 Years
title_sort assessing phenological shifts of deciduous forests in turkey under climate change an assessment for i fagus orientalis i with daily modis data for 19 years
topic MODIS
land surface phenology
NDVI
phenological shift
<i>Fagus orientalis</i>
Turkey
url https://www.mdpi.com/1999-4907/14/2/413
work_keys_str_mv AT tugcesenel assessingphenologicalshiftsofdeciduousforestsinturkeyunderclimatechangeanassessmentforifagusorientalisiwithdailymodisdatafor19years
AT oguzhankanmaz assessingphenologicalshiftsofdeciduousforestsinturkeyunderclimatechangeanassessmentforifagusorientalisiwithdailymodisdatafor19years
AT filizbektasbalcik assessingphenologicalshiftsofdeciduousforestsinturkeyunderclimatechangeanassessmentforifagusorientalisiwithdailymodisdatafor19years
AT meralavcı assessingphenologicalshiftsofdeciduousforestsinturkeyunderclimatechangeanassessmentforifagusorientalisiwithdailymodisdatafor19years
AT hnuzhetdalfes assessingphenologicalshiftsofdeciduousforestsinturkeyunderclimatechangeanassessmentforifagusorientalisiwithdailymodisdatafor19years