Satellite image shows woods of Estonia

Photo: Kristjan Teedema

Forest i.e. biomass may be used as fuel. Being an energy source for power plants. Also being a building material. In addition to that, forest takes up lots of space, of course – but how much, exactly?

Let’s say you by some forest land. The plot will be measured out in hectares, and by plain sight it seems you now possess plenty of forest. But how much timber did you actually get?

To know for certain how much forest plots of Estonia hold, University of Tartu scientists teamed up with Regio and birthed a satellite remote sending map, or, to put it simply, a picture of what Estonia looks like with its forest massif i.e. biomass specified.

Kaupo Voormansik, physics doctoral students in his third year, has, in his thesis, prepared a satellite picture of Estonia with volumes of forest written over it.

Forest algorithm

True, aerial photographs may reveal places with and without forests. However, they will not reveal the type of the forests, nit the amount of cubic metres at definite locations. Also: flying a plane over Estonia and shooting pictures would take at least one year.

In order to get a detailed and fast overview, University of Tartu scientists have figured out an algorithm which, taking into account the types of forests found in Estonia, is able to compose a satellite picture, helped by radar.

The radar sending forth micro wave impulses, able to penetrate tree leaves and crowns, «listening» for signals reflected from branches and trunks. In the basis of such information, it is possible to determine the amount of forest or biomass in an area.

Estonia is about 50 per cent woodland. As this category includes all land able to grow forest, clear cut areas also fall under woodlands – therefore, woodland volumes provide not the actual amount of trees.

Kaupo Voormansik therefore explains that, according to satellite images, we do have 35-40 per cent of forest land.

Good for forest owners

The images might prove profitable for Estonia’s forest owners. For instance: managing a huge forest massif is no piece of cake; should clear cutting happen somewhere, it may only be discovered after a long while. Satellite monitoring might provide them with fresh pictures, every four months.

That being the time it took to put all of Estonia’s biomass unto a map.

Thus, the entire Eurasia’s biomass might be mapped three or four times a year. Considering the smallness of Estonia, an overview could be secured quite often, bringing many a benefit.

For instance, the info can be used when building combined heat and power stations, saw gates or other timber production facilities. It being prudent to build these where the trees are near – avoiding transportation from far away.

Biomass

• 64 per cent of renewable energy produced in Estonia comes from biomass. Therefore, it is important to know where the biomass is located, and in what volumes.

• In addition to forest, algae, plants, animals etc may also counted as biomass.

• Using a remote sensing satellite, it is possible to determine by strength of signals reflected from tree trunks, how many trees definite areas hold. The stronger the reflected signal, the more timber.

• An algorithm was developed for satellite remote sensing images by scientists of University of Tartu. The map was compiled by AS Regio, using satellites of European and Japanese space agencies.