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Earth Observation Serving Europe´s Forested Regions

Operational satellite-based Earth Observation services support the forestry sector.

The challenge

The forestry sector is having to quickly adapt on a regional basis to economic, social and environmental changes. Certain areas are under increasing pressure from human activities while others are becoming settlement deserts. Renewable energy targets are also part of the picture. One big question is how forests can maintain the multi-faceted range of services they offer. Furthermore, in a changing natural environment climatic events are also taking a toll through storm related windfall damage, droughts and conversely waterlogging, and fire events. Parasite attacks can also affect already weakened forests. All of this is occurring during a period of budget cutbacks that make the management of Europe’s vast forests even more complicated. Forest fire monitoring, la Réunion using RapiEye imagery, SERTIT 2011

Through long-term R&D collaboration (Interreg and public conventions) and now contracts with SERTIT, the forest sector in NE France (Alsace-Lorraine) accepts that satellite remote sensing can offer solutions, tools to help them manage their forests. The challenge is to continually foster and expand this collaboration and to provide operational results. Moreover, the forest bodies realise that remote sensing does not replace them, but is a useful, timesaving and complementary tool to their work and can be integrated into their workflows. The results often make their work possible and open-up new horizons. As one can expect, part of the challenge as always is to fund this work; with SERTIT and its private and public partners exploring ways to source finance for both R&D and production activities.

Benefits to citizens

Forests and trees provide numerous services from building material and fuel, contributing to many industrial products. Together with grasslands and other permanent natural land surfaces, forests provide precious habitats and corridors for the movement of fauna and otherwise contribute significantly to biodiversity. Forests and trees also provide healthy leisure amenities, enrich the landscape and reduce urban heat islands. They break-up urban landscapes providing diversity and reducing stresses including noise, visual and chemical pollution. Indeed, terms such as green infrastructure are being used to describe our environmental assets of which forestry is a very important part.

Remote sensing derived geographical information can help in the sustainable management of these forests, highlighting trends in forests, an integral part of many European citizens’ landscapes, locating where they are developing or are under pressure, being conserved or exploited. It is recognised by the forest sector that this information would often be too expensive to obtain in the field. Importantly, the regional forestry sector’s viewpoint towards remote sensing is improving as useful inputs and solutions to forester issues are coming on-line.

The space-based solution

Earth observation provides a near instantaneous view of forests on a given date. When used for mapping, very precise and exhaustive reference geo-information can be obtained. When combined with archives, trends over fifty years can be mapped to analyse landscape changes from the 1960s to the present day. Forest clearings and plantations and resources monitored can also be aided by remote sensing. Trends like the higher pressure on small forests, and hence the threat to green infrastructure can be illustrated. Storm windfall or fire damage can be mapped to indicate damage extents. Valuable information can be provided on parasite attack die-offs. This work is validated in situ by foresters.

Specifically, in mountainous terrain satellite imagery helps monitor tree-felling amongst the private small-holder plots of the Vosges Mountain Range. This prized resource is diminishing with little replacement being observed by the foresters inciting the sector to establish replanting funds with calls for this and the remaining resource to be regularly monitored through remote sensing. Here SERTIT works with private forester bodies (CRPF Lorraine-Alsace and Cosylval). In another development the Fédération Interprofessionnelle Forêt-Bois Alsace (FIBOIS Alsace), has funded a multi-disciplinary storm preparedness dossier, including tree-type and 3-D information on forest plantations in-part derived from remote sensing data, to improve post-storm responsiveness. The overall aim is to facilitate the planning and preservation of forestry landscapes and resources with satellite imagery being used to objectively monitor forestry dynamics.

In areas of high human pressures on forests, SERTIT has proven the capacity of satellite imagery to efficiently pinpoint tree-felling and whether they lead to changes, with trees often being replaced by other land-uses (urban, primary resource extraction and vineyards)

This long-term 20-year service has been supported, validated and the results used by the Regional Delegation of the Agricultural and Forestry Department (DRAAF) within the application of Regional Forestry Policies (ORF). Recently, SERTIT has worked on mapping tree die-offs contributing to the Ministry of Agriculture, Agri-food and Forestry’s (MAAF) work in the aftermath of post-storm bark beetle infestations. This along with windfall mapping and fire mapping constitute part of our broadening extreme event and emergency portfolio. Forest clearing in Alsace over 20 years using SPOT imagery, SERTIT 2011

Outlook for the future

The continuity and expansion to other geographical sectors of the above-mentioned regional services is envisaged. More regular imaging at a lower cost by ESA’s Sentinel satellites should enhance the possibility of remote sensing services providing pertinent, more detailed information on the richness of our forests. The forest sector is requesting information on volume estimates and hence 3D applications will probably come on-line facilitated by, amongst others, the French Pléaides constellation and German Tandem-X resources. In other areas, emergency-mapping services will improve provision to civil security authorities and foresters alike.

It must be stated that Interreg and to a lesser extent GMES projects have helped co-fund R&D developments which have fed into better services for the forestry sector. One such Interreg project, backed by the Alsace Regional Council, concerning the Sweet Chestnut tree in the Upper Rhine Valley, has led to a rethink by foresters on the resource’s viability (Cosylval) after SERTIT highlighting chestnut tree concentrations. This could promote chestnut tree conservation as they become valued. Generally, at the request of foresters, SERTIT will look further into tree species and structure mapping.

Furthermore, SERTIT is exploring the use of sub-metric optical imagery (Pléiades) in suburban and urban tree mapping as regards land-planning, green-infrastructure and endangered biotope mapping. A considerable effort is made to automate much of the required procedures, with the Strasbourg Urban Community working with SERTIT in this domain.

Finally, and further to the monitoring of forests, SERTIT will investigate 3-D forest resource mapping, post-fire potential effects on soil plus die-offs and regrowth, and perhaps the effects of extreme events in terms of lost tree volumes. It must be said that the CNES, the French Space Agency, and the European Space Agency have given SERTIT a helping hand wherever possible and over many years notably concerning access to data and technological developments.

Cost justification and Return on Investment

As is often the case in this domain it is difficult to come up with hard and fast figures in a quantitative cost justification. The main justification comes in the form of user groups being satisfied and continuing their collaboration while suggesting more avenues to explore. In certain terms satellite remote sensing facilitates work that would otherwise be too expensive to carry out by traditional means giving extensive yet precise information on forests and their dynamics.

From SERTIT’s point of view, the long-term return on investment is evidenced by the increasing number and range of forestry related activities in which foresters include satellite remote sensing derived information.

Another positive point is that the forestry sector is becoming increasingly exigent and coming-up with requests in new domains and with new, more precise demands using more precise satellite data. They increasingly understand the limits but moreover the benefits that remote sensing derived work can bring to their working environments. They also understand that the most expensive part of geographical information related work is the initial costs of establishing and validating an application or service. The costs reduce over time leading to a certain return on investment and an increased usefulness of the accruing information. In the past this work was nearly always financed through R&D and there definitely was air of techno-push surrounding it, whereas increasingly remote sensing derived geo-information layers are seen as part and parcel of the everyday working environment.

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