부산대학교 도서관

Keywords: broadleaved tree; conifer plantation; DEM; digital elevation model; mapping; old-growth index; snow depth; temperature; terrain; arbol de hojas anchas; DEM; indice de crecimiento antiguo; mapeo; modelo de elevacion digital; plantacion de coniferas; profundidad de nieve; temperatura; terreno; ea[paragraph]ae ; ea[paragraph]aeaea*; ae[degrees]a-e'c[umlaut]ae[umlaut] a (DEM); c'a3/4; eaeaeaeae[degrees]; cs.[macron]e*ae*[+ or -]a*[bar]; ae[cedilla][c]a*[bar]; a[degrees]a1/2cents Abstract Stand structure develops with stand age. Old-growth forests with well-developed stand structure support many species. However, development rates of stand structure likely vary with climate and topography. We modeled structural development of 4 key stand variables and a composite old-growth index as functions of climatic and topographic covariates. We used a hierarchical Bayesian method for analysis of extensive snap-shot National Forest Inventory (NFI) data in Japan (n = 9244) to account for differences in stand age. Development rates of structural variables and the old-growth index exhibited curvilinear responses to environmental covariates. Flat sites were characterized by high rates of structural development. Approximately 150 years were generally required to attain high values (approximately 0.8) of the old-growth index. However, the predicted age to achieve specific values varied depending on environmental conditions. Spatial predictions highlighted regional variation in potential structural development rates. For example, sometimes there were differences of >100 years among sites, even in the same catchment, in attainment of a medium index value (0.5) after timber harvesting. The NFI data suggested that natural forests, especially old natural forests (>150 years), remain generally on unproductive ridges, steep slopes, or areas with low temperature and deep snow, where many structural variables show slow development rates. We suggest that maintenance and restoration of old natural forests on flat sites should be prioritized for conservation due to the likely rapid development of stand structure, although remaining natural forests on low-productivity sites are still important and should be protected. Article Note: Article impact statement: Forest structural development rates vary depending on the environment, and in Japan plantations occupy areas where rates of development of stand structure are fast. CAPTION(S): Descriptions about NFI data (Appendix S1), treatment of structural variables and model structure (Appendix S2), graphical plots of structural variables and varied models (Appendix S3), environmental covariates (Appendix S4), graphical plots of model outputs (Appendix S5), results of cross-validation (Appendix S6), environmental covariates for spatial prediction (Appendix S7), modeling issue of Eq. 2 (Appendix S8), parameter estimates (Appendix S9), and source R codes of the analysis (Appendix S10) are available online. The authors are solely responsible for the content and functionality of these materials. Queries (other than absence of the material) should be directed to the corresponding author. Byline: Yuichi Yamaura,David Lindenmayer, Yusuke Yamada, Hao Gong, Toshiya Matsuura, Yasushi Mitsuda, Takashi Masaki