Determination of a common forest life cycle assessment method for biodiversity evaluation

Forest biodiversity is highly linked with the occurrence of certain forest development phases (fdp) within the forest life cycle. Generally, the disintegration phase provides the highest biodiversity. The objective of the study was to test different existing forest life cycle assessment approaches aiming at developing a common reliable fdp assessment method. We tested and compared three approaches to record fdp in beech, mixed beech and spruce forests, in managed and unmanaged forests, and in four different plot sizes ranging from 125 to 2000 m2. The main results of the fdp comparison are as follows:(1)In approximately two thirds of the cases the three considered methods did not yield a corresponding fdp record.(2)Generally, the larger the plot sizes, the larger the average fdp deviation in forest reserves.(3)The fdp deviation is stronger in beech or spruce dominated forest reserves than in mixed beech forest reserves.(4)Plots of 500 m2 show most distinct numbers of microhabitats corresponding to the fdp sequence within the forest life cycle.(5)Furthermore, the managed forests mostly show lower fdp deviation than the forest reserves.One approach resulted in the most differentiated portrayal of the studied forest structures compared to the other two as shown by the facts that, (a) the studied forests are seen to be divided up into more fdp than when applying the other two methods, and that (b) the dominant fdp changed depending on the forest community and plot size reflecting different growth conditions and probabilities to meet large dimensioned trees during records, respectively, and (c) considering the distribution of microhabitats which are crucial for xylobiontic (saproxylic) organisms, this approach resulted in the assumed biodiversity patterns with increasing microhabitat numbers up to the disintegration phase thus it was used as a basis for the creation of an optimized fdp assessment method as a tool for common and standardized use in forest ecology and biodiversity research.

► We compare three forest development phase (fdp) assessment methods to describe the forest life cycle.
► In two thirds of the cases the three considered methods did not yield a corresponding fdp assessment.
► Generally, the larger the plot sizes, the larger the average fdp assessment divergence in forest reserves.
► The fdp deviation is stronger in beech and spruce forest reserves than in mixed beech forests.
► We provide an improved forest development phase assessment method.