Abstract: The growth conditions of oak trees in Yilan State Forest Farm were surveyed by using the sample plot method. The growth conditions of oak trees in mixed broadleaf-coniferous forest,mixed deciduous broadleaved forest and pure forest were made clear through analysis of variance and multiple comparison. The results indicated that oak tree's DBH annual growth, annual tree height growth and annual volume growth in mixed broadleaf-coniferous forest are higher than mixed deciduous broadleaved forests and pure forest at 18 to 42.Consequently, cultivation of mixed forests with different ages will be important to sustainable management and use of forest resources.

Key words: Quercus mongolica, mixed broadleaf-coniferous forest, mixed deciduous broadleaved forest, pure forest