Abstract: To determine the effects of shade on survival rate, relative growth rate (RGR), biomass allocation and photosynthesis characteristics, potted seedlings of shadetolerant Juniperus sabina and shadeintolerant Pinus sylvestris var. mongolica in lownutrient substrate were grown without shade or under a 35%, 65% or 95% reduction of full sunlight over two growing seasons. The results showed that, with decreased light availability, J. sabina growth and survival did not change significantly. Total biomass and RGR increased and then decreased; RGR indicators were positive; and the shoot/root ratio increased significantly. In contrast, the survival rate and growth of P. sylvestris var. mongolica decreased significantly. Total biomass and RGR decreased; the RGR was negative under 95% shade; and the shoot/root ratio decreased significantly. The maximum photochemical efficiency (F_v/F_m) of J. sabina was more sensitive to shade and increased significantly under 35% shade, while the F_v/F_m of P. sylvestris var. mongolica increased significantly until 65% shade. A JIPtest showed that the standardized fluorescence values (V_t) of J. sabina under shade were lower than those under the nonshading treatment (CK) from initial O phase to final P phase. Furthermore, the proportion of electron energy across the Q_A reaction center to the whole energy captured (ψ_o), quantum yield of electron transfer (ψ_Eo), size of plastoquinone pool (S_m), plastoquinone pool reduction rate (S_m/T_fm), number of reduced primary quinone acceptors (N), and energy for electron transfer per excited crosssection (ET_o/CS_o) all increased. The density of reaction centers (RC/CS_o) increased, while dissipation per excited crosssection (DI_o/CS_o) and per reaction center (DI_o/RC) decreased, leading to significantly higher performance indexes (PI_ABS, PI_CSo, PI_CSm) under shade than under CK. The V_t of P. sylvestris var. mongolica under shade was higher than under CK from O phase to P phase; however, the above fluorescence parameters were lower or were not significantly different under shade except for the heat dissipation indexes. DI_o/RC remained unchanged in P. sylvestris var. mongolica under shade, and the performance indexes (PI_ABS, PI_CSo and PI_CSm) also remained unchanged. The above results indicated that J. sabina was able to maintain high growth and survival under low light intensity by maintaining a positive carbon balance and increasing the proportion of aboveground biomass and electron transfer energy levels during the lightreaction stage. In contrast, P. sylvestris var. mongolica had a low survival rate due to a carbon budget imbalance, and the decreases in proportion of aboveground biomass and electron transfer energy level under shading conditions.