Fear drive
As fear drives (also called replacement, stress or Nottrieb) in the jargon Proventivtriebe referred that occur in trees with increased stress. They arise from sleeping buds . Most of them are vertical shoots that a tree forms on the top of the main branches. This happens particularly often at the boundaries of the annual shoot, the end of the sections of the branches that have newly grown in a growth period. In some trees, such as the yew , fear instincts also develop directly on the trunk.
There are different approaches to explanation:
- Fear instincts presumably serve to replace the lack of photosynthesis and transpiration performance of the other instincts, which have been damaged or died, for example, by air pollutants and the resulting dehydration.
- Fear drives are "structure-driven". Once neighboring plants the free space above the too strong treetop harass, growth limited to a few branches, win the (different from the normal branching pattern) altitude quickly and can occupy so free, necessary for photosynthesis space.
See also
literature
- Erlbeck, Haseder , Stinglwagner : Das Kosmos Wald- und Forstlexikon , Kosmos-Verlag, 1998, ISBN 3-440-07511-7
Web links
Commons : fear instincts - album with pictures, videos and audio files
Commons : fear instincts - collection of images, videos and audio files