Height Growth of Korean Pine Seedlings Planted under Strip-Cut Larch Plantations in Northeast China

To develop two-storied forest management of larch plantations in Northeast China, this study examined the height growth of Korean pine (Pinus koraiensis Sieb. et Zucc.) seedlings planted under strip-cut larch canopies. We measured the height growth of the underplanted seedlings 4 years after planting. The larch canopies were of varying stand age (12, 17, and 37 years) and stripcut width (4.5, 6.0, and 7.5 m). We measured the seedling height growth in an open site (i.e., a site with no canopy). Underplanted seedlings had a smaller height growth (12.1-20.1 cm year −1 ) than the seedlings planted in the open site (23.7 cm year −1 ). The seedlings underplanted in the wider strip-cuts tended to have greater height growth than the seedlings underplanted in the narrowest stripcuts. A generalized linear mixed model analysis predicted the greatest seedling height growth in the open site. A 36-47% reduction in annual height growth was predicted for the narrowest strip-cuts (4.5 m) versus the open site, while a 13-36% reduction in annual height growth was predicted for the wider strip-cuts (6.0-7.5 m) versus the open site. To maintain adequate height growth, forest managers are recommended to create wider strip-cuts (i.e., ≥6.0 m) for the purpose of underplanting Korean pine seedlings in larch plantations