Disturbance history and natural regeneration of an old-growth Korean pine-broadleaved forest in the Sikhote-Alin mountain range, Southeastern Russia

Abstract

We used a dendroecological approach to reconstruct the disturbance history of the old-growth Korean pine (Pinus koraiensis Siebold et Zucc.)-broadleaved forest in the southern part of the Sikhote-Alin mountain range (Southeastern Russia). We also performed a point pattern analysis to study the population structures of the five dominant tree species, and our findings demonstrate that there were no intense, stand-replacing disturbances from 1800 to 2000. Low- and medium-intensity disturbance events predominated, and the most probable cause of these disturbances was windthrow due to strong winds. The age structure of the coniferous species indicates recruitment continuity, so the stand is unevenly aged, but regeneration waves associated with the disturbances can be distinguished. The population structure of the dominant species is characterized by similar features, and the aggregate distribution pattern is typical of immature plants. The virginal and generative plants of most species are uniformly distributed, but the generative individuals of some species tend to be hyperdispersed over a small spatial scale. The advanced regeneration pool is mostly composed of immature plants of both shade-tolerant coniferous and light-demanding deciduous species, which confirms that immature deciduous species are characterized by significant shade tolerance, although to a lesser extent than coniferous plants. In virginal plants, light demand is greater for both coniferous and deciduous species. The populations of the dominant species are stable, so the current disturbance regime promotes the coexistence of shade-tolerant and light-demanding species but affects the abundance of the various plant species in the stand.