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Forest spatial structure has always been an important topic of ecological research. Large trees directly affect the spatial patterns in forest stands. In this study, we used the data from seven sample plots in natural mixed forests of Korean pine (Pinus koraiensis Siebold & Zucc.) and broad-leaved trees in Heilongjiang Province, China, to examine the effect of large trees on the spatial distribution of adjacent trees and to explore whether this effect is related to the gap dynamics theory. We classified trees with wide diameter (diameter at breast height (DBH) ≥ 50 cm) as central trees and then surveyed the distribution of adjacent trees around each central tree. The results revealed a ring structure of small trees (size class 2 (5.0 ≤ DBH < 10.0 cm) and size class 3 (10.0 ≤ DBH < 30.0 cm)) surrounding large trees. In the two northern sample plots, the trees formed the ring structures with radii of 4–7 m from the large-diameter trees. In the two central sample plots, the ring structures had the radii of 5–9 m and 5–8 m. Analogously, in the three southern sample plots, the ring structures had the radii of 7–11 m and 6–10 m. The formation of a ring structure is closely related to the competition among individuals, and there is an internal relationship between the formation of this structure and the dynamic theory. [ABSTRACT FROM AUTHOR]

The Integrated Biosphere Simulator (IBIS) has mainly been applied to simulate carbon and water cycles at large spatio-temporal scales, but has not been localized, validated, and applied in Chinese forests. In this study, we first localized the IBIS to forest regions in Northeastern China, simulated net primary production (NPP) and soil respiration (RS) at stand scales, and validated the simulations with measurements from seven and six representative forest types in this region, respectively. Secondly, we explored spatial patterns of the NPP and RS with the localized model and forest inventory data from 881 sample points and meteorological data from 194 weather stations across the study area. We found that the model simulations of NPP and RS agreed well with the measurements, and the relative error introduced varied with vegetation types and years. The relative difference between simulated and measured values varied from 3.8% to 18.0% for NPP, and from -13% to 16% for RS. The spatial patterns of both NPP and RS showed a significant dependency of the vegetation type, temperature, and precipitation. The study demonstrates that the validated localized IBIS can be applied to simulate spatial and temporal dynamics of NPP and RS in temperate forests at both stand- and regional scales. [ABSTRACT FROM AUTHOR]

Methods for the ecological-geographical analysis of the Manchurian Natural Area are discussed to perform estimation of the contemporary state, monitoring, and conservation of the biodiversity of Korean pine broad-leaved forests. The models used for conservation of the mountain Korean pine broad-leaved forests in the transboundary areas of Russia, China, the Democratic People's Republic of Korea (DPRK), and the Republic of Korea should be based on the coordinated management of national resources. Estimating the ecological potential of Korean pine broad-leaved forests and the state and role played by forest ecosystems in the contemporary structure of the vegetation cover of the Manchurian Natural Area is significant for a more successful management of forests and scientifically grounded distribution of the nature reserves to conserve biodiversity. The united ecological-geographical system taking into account the regional peculiarities of forests can serve as a key in the development of the conservation of the biome. [ABSTRACT FROM AUTHOR]