Decreasing the forest ecosystem leaf-area index error (LAIe) helps accurately estimate the growth and light energy utilization of aboveground foliage. Analyzing light transmission in forest ecosystems can effectively determine LAIe. The LAI-2200 plant canopy analyzer (PCA) is used extensively for rapid field-effective LAI (LAIe) measure-ments and primarily to measure forest canopy LAIe values. However, sometimes this parameter must also be measured in forests with small clearings. In this study, we used the LAI-2200 PCA to obtain one A-value and four B-values each for the canopy, herbaceous layer, and forest ecosys-tem LAIe. Field measurements showed that the three LAIe types were obviously different. In certain quadrats, the average herbaceous layer (Dicranopteris dichotoma Bh.) LAIe apparently exceeded that of the Pinus mas-soniana forest ecosystem. The sources of this error were measuring and recording A-value readings for small canopies and underestimating the ecosystem LAIe. We obtained similar coefficients of determination for both the pre-recomputation and post-recomputation of the canopy and forest ecosystem LAIe (R2 ≥ 0.96 and R2 ≥ 0.99, respectively); thus, the error was decreased. Measuring field LAIe with the LAI-2200 PCA and recomputation should compensate for LAIe underestimation in complex forest ecosystems.