Satellite classification of tree species
The reason why this is complicated is that a single tree is less than 30 mand there can be 2-4 trees species in a single pixel. Furthermore, in a satellite image, many tree species look very similar during the peak of summer. However, phenology varies greatly among tree species. Some trees have their leaves earlier, some ater. In the fall, some trees are losing leaves in September while others keep them till the first frost.
By analyzing satellite images for the entire growing season, one can analyzes so-called phenology curves. Over the course of a year, this curve looks different for different species because of phenological differences. This idea sounds quite promising but there is another challenge: Landsat, the source of 30 m imagery, provides only 1-2 images per months. In Poland, where leaves can fully come out in two weeks, this is not frequent enough to build a good phenological curve. This is why Konrad will combine Landsat data with imagery from other satellite sensors, including MODIS and Sentinel 2a.
Ultimately, the maps that Konrad is creating will be beneficial for several purposes. Describing and counting trees in the field takes a lot of time and money. Mapping maps of tree species from satellite images instead will save money and provide more timely information. With such maps, foresters can then estimate current situation on various species, amount of timber and its economic value, and eventually provide better management.