Estimation of seasonal changes in leaf area index based on optical methods in spruce-fir valley forest. Canopy structural parameters and understory light regimes of 3 artificial forest stands in South China METHODS FOR DETERMINING CANOPY LEAF AREA INDEX OF PICEA CRASSIFOLIA FOREST IN QILIAN MOUNTAINS, CHINA Measuring seasonal dynamics of leaf area index in a mixed conifer-broadleaved forest with direct and indirect methods Improving the accuracy of indirect methods in estimating leaf area index using three correc-tion schemes in a Larix gmelinii plantation Estimation of leaf area index of secondary Betula platyphylla forest in Xiaoxing‘an Mountains Estimating the canopy coverage of Picea crassifolia forest using digital hemispherical photography in Qilian Mountains Extracting the canopy structure parameters using hemispherical photography method