Fragen zu Wachstum, Vegetationszeit und Klimawandel

2001

S. 273-275

7 Lit. Ang.

Unselbständiges Werk

200084095

Climate changes in Germany along an east-western gardient from aridity to humidity. Compared with the site tables of Wiedemann many young stands in the western region show an increased growth. This may be influenced by a longer vegetation period in the atlantic climate. Measured in days of vegetation period the stands here are older than their eastern neighbours. In higher ages their height growth in comparison with the site tables may be reduced by wind influence. The vegetation period in Scandinavia decreases along a south-north gradient. However, as day length increases in the same direction it might be more accurate to measure vegetation time in hours. On the other hand the influence of higher day length is more than equalized by lower temperature, so that northern stands show a lower yield. Besides the volume growth the shape of the trees may be influenced by a shorter beginning of the vegetation period and lateral growth is extended over the whole period, a shortened time for growth will slow down the lateral growth, leading to slender crowns. These relations are getting more complicated by global warming. A higher CO2 level will lead to an augmentation in photosythesis but not the whole gain in energy will be invested in biomass growth. It is expected that plants at a higher CO2 level need less radiation, have a better water use efficiency and a widened C : N ratio. At the same time respiration is enlarged and my take away a higher amount of BPP (brutto primary production). To improve management decisions it is important to be more cautious against forecasts and to intensify research.