potential benefits that sentinel-2 data could bring to...

Potential benefits that Sentinel-2 data could bring to characterise and monitor forestry,

simulated through SPOT 4 Take5 data

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Colette Meyer1, Stephen Clandillon1, Henri Giraud1, Mathilde Caspard1, Jérôme Maxant1, Hervé Yesou1, Paul de Fraipont1, Arnaud Selle2

1SERTIT, France; 2CNES, France

Sentinel 2 For Science Workshop ESRIN, Frascati, Italy 20-22 May 2014

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Applications Land management and urban planning

Natural resource monitoring Environmental studies

Natural disaster and risk management

National and international research projects

Specification of future space systems Image processing methods

Validation and qualification tools Geoinformation based expert systems

Resources A multi-disciplinary team Remote sensing and GIS specialised equipment A research/university environment within Strasbourg university

Sentinel 2 For Science Workshop – ESRIN, Frascati, Italy – 20-22 May 2014

SERTIT, a remote sensing and GIS technological transfer service

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SERTIT’s experience in forest monitoring

1990 SPOT 2

1999 SPOT 4

2002 SPOT 5

2009 SPOT5

20 years monitoring

Mapping the changes between each image pair...

Forestry under pressure on the Alsace plain

- encroaching urbanization - other landuses such as vineyards


Long-term inventory and monitoring on a regular basis of forest clear cuts using Sentinel-2 type data (SPOT)

Forest clear cuts between Mapping on the Alsace plain

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SERTIT’s experience in forest monitoring Natural disaster impact mapping Lothar Storm windfall damage, Alsace

SPOT 4 September 1999 image, acquired just before the storm

SPOT 5 September 2002 image, acquired after storm at the request of foresters

December 1999 The devastating Lothar

and Martin storms struck Western Europe

Windfall damage

Early mapping studies Before and after Coherence Radar Products (CAR) used to detect storm damage (ESA study , 2001)


Windfall damage mapping on the Alsace region

5 Sentinel 2 For Science Workshop – ESRIN, Frascati, Italy – 20-22 May 2014

Coniferous

Deciduous

Aims: • Up-to-date inventory & 3D forestry terrain analysis • Integrated into the official storm preparedness dossier

Forest inventory distinguishing between coniferous and deciduous stands in 2009

…forestry terrain 3D analyses

SERTIT’s experience in forest monitoring

Part of a multi-disciplinary effort to preparing for the next storm to hit Alsace Region

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SPOT4 Take 5 programme by CESBIO

o Simulation of Sentinel 2 data

o Images acquired between February and June 2013

o High data acquisition frequency (an image every 5 days)

o 20m visible, near infrared and mid-infrared bands Study objectives

• Tree species differentiation over the Alsace plain‘s deciduous forests with SPOT4 Take 5 data

• Use of field data originating from public (ONF, Office National des Forêts) and private (CRPF) sector foresters (tree species, stand structure and typology)

In other words:

Tree phenology evolution can be followed every 5 days with the dataset

Does the high frequency monitoring help to better differentiate between tree species?

Forestry - Tree species differentiation Using SPOT4 Take 5 programme dataset

Funded by a R&T CNES Programme

SPOT4 Take 5 covering area

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23/04 08/05 18/05 02/06 07/06 17/06

o SPOT 4 data acquisition during the vegetation development phase between February and June 2013

o An unlucky acquisition programme, Spring 2013 was one of the most cloudy on record

o Not possible to use the cloudy February, March and early April images, only the 4th of March data cloudless

o Partial use of the images acquired after the 23rd of April, only one is almost cloudless (the17th of June)

Acceptable image data

Forestry - Tree species differentiation Sentinel 2 simulation SPOT4 Take 5 dataset

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Analysis of the multi-temporal data’s spectral characteristics per deciduous species during the vegetation development period:

• with the SPOT4 Take 5 dataset

• using field samples of representative, pure, mono-species forestry parcels,

• supplemented by field campaigns nearly synchronous with satellite image acquisitions in order to register the phenological development phase.

Deciduous tree-species: pedunculate oak and beech (the main species), red oak, poplar and black locust

Forest samples where selected in areas with no cloud cover in the selected SPOT 4 Take 5 data

Location of the field samples

Forestry - Tree species differentiation Methodology

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Field observation

SPOT 4 acquisition Beech Beech

Pedunculate oak

17/04 26/04

Pedunculate oak

Field campaigns realized from late April to early May:

• survey with photos describing the phenological development phase in the field with GPS positioning

• not always useable because of cloudy acquisitions

• most of the vegetation’s development took place rapidly within a few mild and sunny days (17 - 26 Avril) after a cool and cloudy period

Forestry - Tree species differentiation Field trips

23/04 08/05 18/05 02/06 07/06 17/06

06/05

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Second Date Third Date

First Date

Beech Red oak

All parcels alike More vegetation on beech parcels

Leaves of beech and red oak parcels are not developed

Use of mono-species forestry parcels extracted from private sector forester databases

Forestry - Tree species differentiation Multi-temporal spectral analysis

Case study 1: Haguenau 23/04 08/05 18/05 02/06 07/06 17/06

SPOT 4 acquisition

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Red oak / Beech are separable in early May

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Case study 1: Haguenau

Beech

Red oak

SPOT 4 acquisition

23/04 08/05 18/05 02/06 07/06 17/06

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Very white black locust sectors clearly visible

Brighter-coloured black locust areas Presence of only oak leaves

Pedunculate oak

Black locust Red oak


Case study 2: Epfig 23/04 08/05 18/05 02/06 07/06 17/06

Second Date Third Date

First Date

Use of centres from square mono-species forestry grid samples (ONF, public forestry sector)

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06/05

Black locust

Red oak http://apistory.fr/PAGES/robinier.html

Field observation SPOT 4 acquisition


Case study 2: Epfig

23/04 08/05 18/05 02/06 07/06 17/06

Pedunculate oak

Black locust

Red oak

The flowering black locust

Black locust is highly separable early June

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European Regional Development Fund European Territorial Cooperation

2007-2013

Forestry - Tree species differentiation The Chestnut in the Upper Rhine Valley

o A multi-partner Franco-German study within an Interreg IV Upper Rhine project

o The study aims to conserve and valorise the Chestnut tree, a species that overlooks the vineyards of the area

o Presently, this tree is sometimes victim to die-offs caused by a canker

o In this project, SERTIT mapped chestnut tree plantations using Sentinel 2 type data (SPOT 5) from a multi-date imagery database

Field Validation campaign by foresters (CRPF) • 52 control points in chestnut tree

stands • Field surveys for each point of the

proportion of chestnut tree cover

Presence of chestnut trees at 96 % of control points

81%

9% 6% 4%

>= 75%

50 - 75%

25 - 50%

0%

Chestnut tree proportion survey

Chestnut tree mapping on the Alsace Region


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Chestnut late budding in spring Profuse flowering in July

April July

Oak

Beech

Chestnut

Red channel spectral responses

Development of a methodology for chestnut tree mapping with multi temporal SPOT 5 data and using deciduous tree field samples


September

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• Tree species differentiation is illustrated using the SPOT 4 Take5 time series despite the thick cloud cover during the acquisition period

• Promising results have led to interesting ideas for future studies in the field of tree species mapping, especially with Sentinel 2 data

• Sentinel 2 will offer: o a year-round monitoring , covering the whole forestry species vegetation cycle,

o a multi-annual acquisition time-span, so bad weather conditions can be accommodated,

o a worldwide coverage,

o an increased potential with the wider range of spectral bands (Red edge, SWIR), o a guaranteed long term coverage (with S2A, B, C…). …which together should open the Horizon to new and interesting forestry applications

Forestry - Tree species differentiation Conclusion

Parc d'Innovation, Bd. Sébastien Brant, BP 10413 67412 ILLKIRCH CEDEX- France

Tel: +33 (0)3 90 24 46 47

Thank you for your attention [email protected] http://sertit.u-strasbg.fr/

Sentinel 2 For Science Workshop ESRIN, Frascati, Italy 20-22 May 2014

http://sertit.u-strasbg.fr/








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