Longitudinal Growth Patterns and Climate Responses of Larix olgensis Trees Differing in Size and Survival Status

Growth decline before tree death has attracted increasing attention under climate change and plantation ageing. However, most previous studies have relied on diameter at breast height (DBH) or tree-ring measurements at breast height and have given limited consideration to longitudinal variation along the stem. Using multi-height tree-ring-width data from a Larix olgensis A. Henry plantation in the Wanda Mountains, we compared radial growth, annual volume increment (AVI), and seasonal climate responses among small living trees (SL), large living trees (LL), and dead trees (DT). LL maintained greater TRW than SL across all sampling positions and greater BAI than both SL and DT across relative stem heights, whereas no significant BAI difference was detected between SL and DT. Recent TRW trends declined at several relative heights in SL and DT, whereas the decline was weaker in LL. AVI trajectories peaked earliest in DT and latest in LL; mean net AVI change differed among groups (η2 = 0.428), remaining positive in LL but negative in SL and DT. LL exhibited a coherent negative temperature response across stem positions, whereas the DT association was concentrated at 75% stem height. Together, multi-height TRW, BAI, and AVI identified sustained whole-stem growth as the defining feature separating LL from SL and DT. These findings identify longitudinal stem variation as a key dimension of growth histories and climate sensitivity among trees differing in size and survival status.