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Investigating the spatial distributions and associations of tree populations provides better insights into the dynamics and processes that shape the forest community. Korean pine (Pinus koraiensis) is one of the most important tree species in broad-leaved Korean pine mixed forests (BKMFs), and little is known about the spatial point patterns of and associations between Korean pine and community-level woody species groups such as coniferous and deciduous trees in different developmental stages. This study investigated the spatial patterns of Korean pine (KP) trees and then analyzed how the spatial associations between KP trees and other tree species at the community level vary in different BKMFs. Extensive data collected from five relatively large sample plots, covering a substantial area within the natural distribution range of KP in northeastern China, were utilized. Uni- and bivariate pair correlation functions and mark correlation functions were applied to analyze spatial distribution patterns and spatial associations. The DBH (diameter at breast height) histogram of KP trees in northeastern China revealed that the regeneration process was very poor in the Changbai Mountain (CBS) plot, while the other four plots exhibited moderate or expanding population structures. KP trees were significantly aggregated at scales up to 10 m under the HPP null model, and the aggregation scales decreased with the increase in size classes. Positive or negative spatial associations were observed among different life stages of KP trees in different plots. The life history stages of the coniferous tree group showed positive spatial associations with KP saplings and juvenile trees at small scales, and spatial independence or negative correlations with larger KP trees at greater scales. All broad-leaved tree groups (canopy, middle, and understory layers) exhibited only slightly positive associations with KP trees at small scales, and dominant negative associations were observed at most scales. Our results demonstrate that mature KP trees have strong importance in the spatial patterns of KP populations, and site heterogeneity, limited seed dispersal, and interspecific competition characterize the spatial patterns of KP trees and community-level spatial associations with respect to KP trees, which can serve as a theoretical basis for the management and restoration of BKMFs in northeastern China. [ABSTRACT FROM AUTHOR]

Recent studies suggest that the mycorrhizal type associated with tree species is an important trait influencing ecological processes such as response to environmental conditions and conspecific negative density dependence (CNDD). However, we lack a general understanding of how tree mycorrhizal type influences CNDD strength and the resulting patterns of species abundance and richness at larger spatial scales. We assessed 305 species across 15 large, stem‐mapped, temperate forest dynamics plots in Northeastern China and North America to explore the relationships between tree mycorrhizal type and CNDD, species abundance, and species richness at a regional scale. Tree species associated with arbuscular mycorrhizal (AM) fungi showed a stronger CNDD and a more positive relationship with species abundance than did tree species associated with ectomycorrhizal (ECM) fungi. For each plot, both basal area and stem abundance of AM tree species was lower than that of ECM tree species, suggesting that AM tree species were rarer than ECM tree species. Finally, ECM tree dominance showed a negative effect on plant richness across plots. These results provide evidence that tree mycorrhizal type plays an important role in influencing CNDD and species richness, highlighting this trait as an important factor in structuring plant communities in temperate forests. [ABSTRACT FROM AUTHOR]

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]

• Large trees dominate temperate forest spatial patterns. • Large trees correlate to diversity and species coexist. • A ring of small conspecific trees is found around the large tree. • Conspecific negative density dependence explains the pattern formed by large trees. • The ring-like structure promotes the succession and regeneration of the temperate forest. Large trees have been found to directly affect spatial patterns in forests and understanding forest spatial structure is important for developing effective forest management practices. We examined two primary broad-leaved Korean pine forests in Heilongjiang Province, China, to investigate the effects of large-diameter trees on the distribution of adjacent conspecific trees and to assess whether the effect is related to the conspecific negative density dependence hypothesis in temperate forest. We classified the tree with the widest diameter (diameter at breast height ≥ 50 cm) as the central tree and then surveyed the distribution of adjacent trees around each central tree. The degree of mingling between the central tree and adjacent trees was the lowest at 5–7 m. As the diameter of the adjacent trees increased the degree of mingling declined. This revealed that around the central tree, there was a ring of small trees conspecific to the central tree. The ring-like structure around large-diameter trees is consistent with the conspecific negative density dependence hypothesis. Thus, we propose that a ring-like structure promotes the succession and regeneration of the temperate forest. [ABSTRACT FROM AUTHOR]

With natural Pinus koraiensis population as test object, and by the methods of growth equation regression analysis and partition fitting determination, this paper studied the neighborhood interference radius of P. koraiensis at various slope locations. The results showed that there was a significant negative correlation between the neighborhood interference index and the growth of P. koraiensis, and the correlation level varied with neighborhood interference zone and slope. The interference zone corresponding to the maximal regression coefficient R2 was considered as the neighborhood interference radius. Based on the linear subsection regression between neighborhood interference index and interference zone, the neighborhood interference index increased fast and then slowly as the zone expanded, and the interference zone corresponding to the transition point was considered as the neighborhood interference radius. The neighborhood interference index was positively correlated with neighborhood interference zone, and the range of R2 was 0.41 - 0.55. The neighborhood interference radius of P. koraiensis varied with slope locations in the order of lower slope = upper slope > middle slope.

Fenglin National Class Nature Reserve is the largest well-saved virginal Korean pine (Pinus koraiensis) forest area and a precious species gene bank in China. In this study, the indexes diversity, naturalness, representativity, rarity, area suitability, stability, and anthropogenic interference were selected to establish a ranking ecological evaluation system to estimate the ecological condition of the Reserve. The value of each index was determined by the evaluation system, and the weight percentage was decided by Analytical Hierarchy Process (AHP). In the Reserve, there were 568 higher plant species belonging to 113 families and 220 higher animal species, with score 3 of species diversity. The zonal "climax" vegetation type broad-leaved Korean pine forest and the intrazonal community type spruce-fir forest constituted the principal part of the Reserve forest, which was the epitome of the virgin broad-leaved Korean pine forest in Lesser Xing'an Mountains, with representativity score 3. During the past 20-30 years, the natural habitat in the Reserve was quite good, and secondary succession was obtained effective control with few natural or anthropogenic disturbance, with score 4 of naturalness and anthropogenic interference. There were a lot of ancient species of the tertiary period, such as Pinus koraiensis, Fraxinus mandsurica, Juglans mandshurica, Pellodendron amurense, Tilia amurensis and Acer mono, and Pinus koraiensis was listed as one of severe danger species by the FAO of UN, with rarity score 4. The Reserve covered an area of 18165 hm2, with an enough size to maintain the structure and function of the ecosystem. Accordingly, its area suitability score was 4. Broad-leaved Korean pine forest was the most typical and stable vegetation type in the Reserve, and thus, its stability score was 4. Finally, the composite evaluation index (CEI) was figured out as 0.87, showing that the ecological quality of the Reserve was very good, and the protection value was quite high. In conclusion, the present area, structure, and management of the Reserve could satisfy the requirement of sustainable development.