Canopy research

The treetop research ( in English: " Canopy research" ) is a relatively recent branch of biology, whose main objective is to explore the ecological relationships in the top floors of the forests.

With the help of alpine climbing rope technique, hanging bridges, high scaffolding, mobile lifting platforms, large cranes or similar structures, but occasionally of airships of the crown space is made ​​available. Using different methods, for example, animal and plant species, fungi and micro-organisms, their frequency, number of individuals and vertical distribution are recorded. Especially in the tropics applies ride- on branches and twigs of the plant crown area, so-called epiphytes (eg orchids, bromeliads, aroids, but also mosses and lichens) special attention. In addition, physiological data of the trees are determined (eg, transpiration and photosynthesis rates). The framework for such studies form accompanying meteorological studies, such as the measurement of temperature, humidity, radiation and wind speed in the vertical sequence from the forest floor to the canopy and beyond. These studies new species have been discovered in recent years, especially in tropical forests hundreds who were the eyes of the researchers noticed before.

Research organizations

A report by the journal Science, according to now examine the world several hundred physiologists, taxonomists, ecologists and environmentalists, the tree crown regions of different woods. Umbrella organizations of the tree crown researchers are the " Global Canopy Programme " (GCP ) ( in German about: Global treetop program ) and the " International Canopy Network" ( ICAN ) (International treetop network ). The " International Canopy Crane Network" (International Canopy Crane Network ) is a loose research network of cranes or similar access techniques at 11 sites in Panama (2 cranes ), French Guiana, Australia, Malaysia, Japan and Germany (3 cranes), the Switzerland and in a wooded area on the west coast of the USA ( North Oregon). The "Global Canopy Programme " based in Oxford (UK ) plans in the coming years to nine other locations, especially in the tropics (Africa, Brazil, India) research institutions with tree crown access to build (mostly using a crane ).

Research Projects

A main interest of researchers limitation the tree crown the interaction between the "top" and "bottom". In the top floors of forests can in fact be used extensively supported by the trees the sun's energy, for example, to create worksheets that can serve the animals and microorganisms as food source after leaf fall on the ground: The canopy is in some forests, the most productive floor of the forest. In the tropics, however, the upper canopy may also have desert-like conditions, as in full sunlight, the air humidity, in contrast to the shaded forest inside, might be substantially diminished. The organisms of the forest must adapt to these sometimes very pronounced differences. This is one of the reasons why, especially in high and ancient forests in the canopy partly very different species are encountered as on the forest floor.

Through precise and long-lasting observation of individual groups of trees the width growth of the crowns can be further investigated by different species in a mixed forest. Although it is known for a long time that a forest does not have a uniformly high roof, but that different types their crowns at different heights - so staggered - develop. In contrast, a lateral growth is always at the expense of neighboring trees, and to this day is completely unknown what species of trees of a forest are particularly assertive.

The crane of Leipzig Burgaue

Researchers at the University of Leipzig have been working for 20 years, including with the exploration of a native deciduous forest. Since March 2001, Prof. Wilfried Morawetz also made ​​it possible to do this with the help of a crane, which is in near-natural floodplain forest in Leipzig in the northwest of Leipzig in the nature reserve " Burgaue ". The crane is on rails and can be more than 100 meters wide moves. Through him is an interdisciplinary research team of botanists, zoologists, meteorologists, ecologists and forest scientists opened the possibility to study the whole forest to about 35 meters in height and to gain new insights into the flora and fauna of the forest canopy. It surprises the Leipzig Canopy kept ready: With frogs in eastern treetops scientists had not expected, for example.

Was examined, inter alia, the regenerative capacity of the forest, further work on the timing of flowering periods, leaf shoots and fruit ripening, depending on tree species and position in the crown were carried out. Studies on herbivory and the " palatability " of leaves yielded new insights into the eating behavior of spiders and insects, and the results of the studies made ​​it clear that many types of long-term survival are dependent on a natural forest with a high proportion of dead wood.

The framework of the Kranzberg forest

Also since more than a decade to make frame-like platforms in the forest of Kranzberg the crowns of a book holdings in 27 meters height directly accessible. Researchers at the Technical University of Munich study here in the context of the Sonderforschungsbereich 607 of the Deutsche Forschungsgemeinschaft, whether increases in the growth of plants - a prerequisite to in competition with neighboring plants to survive - at the same time leads to a limitation of the ability to fight off parasites.

Furthermore, the researchers infected for example book branches of sun and shade crowns with the fungus Apiognomonia errabunda ( the causative agent of " Apiognomonia - leaf blight " of the book ) and put the leaves after an elevated concentration of ozone. Thus, it was analyzed how the fungus infected leaf types respond to different levels of ozone pollution.

The boom lift from Hainich

The Göttingen Geobotanikerin Annika Naughty examined in the largest contiguous deciduous forest in Germany, the north-eastern of Eisenach Hainich, split with the help of a so-called cherry-pickers, such as different types of trees the canopy among themselves. Their findings from up to 30 meters height suggest that trees can bring not only by the shading of other plants in an advantageous position, but also by robust branches: When a forest tree expands his crown by strong growth, he encounters always and rapidly in the crown area of neighboring trees in front. In a storm then the branches of the competing trees often violently beat each other, which regularly has to irreparable damage; depending robust the branches, the more advantageous will be affected in a storm.

The crane of Hofstetten

Prof. Christian Körner from Basel studied since 1999 with a 45 meter high crane forestry Hofstetten. In this project, grains fumigated a part of the forest with an increased concentration of carbon dioxide (CO2 ), as is expected in the future to explore the impact of these (local) modified atmosphere on the forest and its community of life (animals, plants, fungi).

Other projects

• Professor Nigel Stork from the James Cook University in Queensland (Australia) where he heads the Rainforest Research and scientific coordinator of the Australian tree crown research crane north of Cairns.

• Professor Margaret Lowman is director of the Marie Selby Botanical Gardens in Florida, who specializes in tropical plants. They mainly studied the ecology of the forest canopy and the relationship between plants and insects.

• Prof. Stephen Stillett from Humboldt State University explores the top regions of California giant redwoods and coast redwoods in Redwood National Park and other protected areas in California.

• Research projects at the field station SMEAR II of the University of Helsinki study in a boreal coniferous forest, among other things, the atmospheric chemistry in the top region.