uni'wissen 01(3)-2011_ENG

use the data to analyze aspects of genetic diver- sity, such as the presence of several types of trees, but the researchers are working on it: “To identify tree species we need more than just the geometric data. It’s also necessary to analyze physical information such as the intensity and the amplitude of the radiation, and the method for doing this is not yet ready to be put into prac- tice.” At present, it is only possible to differenti- ate reliably between deciduous and evergreen trees. This limitation notwithstanding, remote sens- ing offers an abundance of possibilities even at the current state of technology. It can be used to identify differences in elevation of less than a decimeter in meadows, fields, and paths. It can automatically capture and model individual trees, tree heights, and the degree of canopy cover in wooded areas. It even allows researchers to cal- culate the stock of available wood and biomass in a forest stand on the basis of the height and density of the trees. “All of this data can be used to develop plans for the sustainable and nature- friendly management of forests. These plans regulate the amount of wood that can be taken from a mature stand and the measures that need to be taken to ensure the stability and natural di- versity of the forests,” explains Koch. “We can then check at regular intervals whether the regu- lations are being adhered to.” Cities Want Laser Data Too One significant factor is the ability of plants to bind carbon dioxide (CO2) from the air. Once one knows the biomass of a forest, one can use it to calculate the amount of gas it can bind. This is the key quantity for the efforts of nations to im- prove their carbon footprint. “Before politicians deliberate about pumping carbon dioxide under- ground, they should determine how much CO2 can be bound by increasing the amount of for- ested areas,” says Koch. According to the Co- penhagen Accord on climate change, countries that increase the size of their forests will receive financial compensation for their efforts. “We could provide evidence of this with the help of remote sensing. Then the rich countries could pay the poor countries for preserving and ex- panding their forests.” Meanwhile, cities, energy corporations, and nature conservation organizations have been call- ing up the department to ask whether they can use its information and algorithms. Three-dimen- sional city models made on the basis of laser data can form the foundation for further environmental models to determine the development of warmth in a city, the houses that would be struck first by a flood, or the optimal location for a solar collector. “Remote sensing with lasers is currently experi- encing a real boom,” says Koch. “Rightly so be- cause it can deliver a lot of information.” “On an aerial photograph I can always locate forests, streets, and paths intuitively. With a laser image I don’t see much at first glance” Red dots become trees and houses: The researchers create three-dimensional models from the laser data step by step.18 uni'wissen 03