Generalized Height-Diameter Models for Three Main Coniferous Trees Species in Changbai Mountain Height-Diameter Model for Major Tree Species in China Using the Classified Height Method Research on Nonlinear Height-diameter Models Simulation of Height-diameter Relationships for Larix gmelinii Based on Mixed Effects Ecoregion based Height-diameter Models for Larix gmelinii Rupr. in Daxing’an Mountains