LAUSR

The patch mosaic–development stage model posits the unity of patches and development stages in primeval temperate forests and links patchiness to the synchronized, coarse-scale canopy senescence, and breakup processes that initiate the demographic transition to new regeneration patches that then asynchronously progress through sequential development stages. Subtle structural differences and inconsistent transitions among development stages observed in primeval forests such as Oriental beech (Fagus orientalis Lipsky) set expected coarse-scale canopy senescence against observed, predominantly fine-scale canopy-gap dynamics. Applying a multi-scale approach to quantify the extent to which stages are characterized by the interspersion of neighborhoods of variously sized trees (i.e., patch types), we investigated patchiness and structural differences in nine Oriental beech stands classified into Initial, Optimum, and Decay stages. Differences among stages in patch type richness and composition occurred primarily at the finest scales and diminished rapidly with increasing scale. Most patch types were ubiquitous and the few patch types unique to a particular stage occurred at very low abundances. Patch types composed of advance regeneration were most prevalent in the Initial stage, but were absorbed into the matrix structure at scales > 500 m2. In all three stages, the most heterogeneous patch type encompassed > 90% of all trees at scales > 100 m2. To portray fine-scale dynamics resulting in similar patch type compositions and structures across development stages, we introduce and discuss the new patch mosaic–gap reabsorption model that avoids the unity of patch and “demographic” stage to focus instead on “structural” stages.