Temporal variation in beech masting (Fagus sylvatica L.) in a limestone beech forest (1981-2004).

摘要

Litterfall data from a Gottinger Wald limestone beech (Fagus sylvatica) forest showed increased beech masting both in terms of frequency of masting events and quantity of nuts from 1981 to 2004. This finding is in agreement with few published long-term studies on the topic in the literature. When analysed against the background of data on climate and nitrogen regime, the pattern appears to be attributable to the following chain of mechanisms: (1) the lack of masting in the previous year (unfilled nutrient reserves); (2) a sunny, warm and dry previous summer (especially during July); since 1980, such summers have occurred much more frequently than in the decades before; (3) a high nitrogen input to fill up the nutrient reserves as soon as possible. However, up until now the increased nitrogen input alone has not been strong enough to induce a more frequent and higher fructification. It is unknown whether masting of beech will become increasingly independent of climate as the nitrogen supply of beech forests increases. A further unknown is the effect of an extended growing season, especially in early spring, and the absence of late frost damage on flowering beech. In contrast to most of the published results, there was no significant relationship at the Gottinger Wald site between fructification and leaf litterfall. The increasing tendency in leaf litter production during the last 25 years is also in contrast with the results of the European forest crown condition assessment..