Production and mortality of fine roots (diameter ≤ 2mm) and influencing factors are important to energy flow and nutrient cycling in forest ecosystems, but remain poorly understood mainly due to the limitation of methodology. In this study, we used a minirhizotron technique to investigate the temporal dynamics in fine root length production (FRP) and mortality (FRM) of five representative forest ecosystems in Northeast China during the period between May and October of 2010. Soil temperature (Ts), soil moisture (Ms), and leaf area index(LAI)were simultaneously measured for each stand. The stands were aspen-birch forest dominated by Populus davidiana and Betula platyphylla, hardwood forest dominated by Fraxinus mandshurica and Juglans mandshurica, Mongolian oak forest dominated by Quercus mongolica, Korean pine (Pinus Koraiensis) plantation, and Dahurian larch (Larix gmelinii) plantation. The experimental design included five forest types, three 20 m×30 m replicate plots in each forest type. The results showed that the FRP and FRM were significantly (P < 0.001) affected by forest types, sampling times and their interactions. The FRP was (13.34±0.90) μm·cm^-2·d^-1 (mean±SE), (13.04±0.82) μm·cm^-2·d^-1, (8.74±1.14) μm·cm^-2·d^-1, (8.02±2.77) μm·cm^-2·d^-1, and (7.59±0.82) μm·cm^-2·d^-1 for the aspen-birch, hardwood, larch, pine, and oak stands, respectively; and the FRM was (5.02±0.36) μm·cm^-2·d^-1, (6.85±0.32) μm·cm^-2·d^-1, (5.05±0.61) μm·cm^-2·d^-1, (3.88±0.35) μm·cm^-2·d^-1, and (3.88±0.61) μm·cm^-2·d^-1, correspondingly. The FRP showed a unimodal seasonal pattern with peaks varying with forest types. The FRM increased gradually as the growing season proceeded, and reached its maximum at the end of the growing season for all the stands except for the aspen-birch and hardwood stands where it peaked in early August. Ts, Ms, and LAI all exerted significant positive effects on FRP and FRM (P < 0.05), which, together, explained more than 68% and 53% of variability in FRP and FRM, respectively. These results illustrated that the temporal dynamics of fine root production and mortality in these temperate forest ecosystems were jointly influenced by changes in soil temperature, moisture and leaf area index.