This study was conducted to clarify the richness patterns of woody plants along a temperate altitudinal gradient on the Baekdudaegan ridge, South Korea. The effects of the spatial and climatic factors on the observed altitudinal richness patterns were evaluated. We also tested Rapoport’s altitudinal effect, which relates the distribution of a species’ altitudinal ranges to the patterns in species richness. Woody plant data were collected from 1100 plots on the Baekdudaegan ridge. A total of 248 woody plant species from 47 families and 99 genera were found. The altitudinal pattern of the woody plant species richness on the Baekdudaegan ridge exhibited a clear hump-shaped pattern with a peak around 800 m. Spatial factors(mid-domain effect and area) were the primary drivers in the simple linear models, whereas the climatic factors(mean annual precipitation and temperature) had lower explanatory power. Multiple linear regression analysis revealed that the combined interaction between spatial and climatic factors affected the altitudinal richness patterns of the overall woody plants. Furthermore, the spatial and climatic factors were more important for large- and small-ranged woody plants, respectively. The results of Stevens’ method and the midpoint method do not support Rapoport’s altitudinal effect. The results suggest that a combined interaction between spatial and climatic factors influences the richness pattern of the total woody plant species. Furthermore, the relative importance of these factors depends on the range size of the woody plants species along an altitudinal gradient on the ridge of the Baekdudaegan ridge.

ABSTRACT
 Introduction
 Materials and methods
  1 Study area
  2 Woody plant data
  3 Explanatory factors
  4 Rapoport’s altitudinal effect
 Results
  1 Altitudinal richness pattern of woody plants
  2 Regression of spatial and climatic factors
  3 Rapoport’s altitudinal effect
 Discussion
 Acknowledgment
 References

• Chang-Bae Lee(Global Resources Team, Korea Forestry Promotion Institute)
• Hyungho Kim(Division of Environmental Forest Sciences(Institute of Agriculture & Life Science), Gyeongsang National University) Corresponding author