Estimation of seasonal changes in leaf area index based on optical methods in spruce-fir valley forest. Estimation of leaf area index of secondary Betula platyphylla forest in Xiaoxing‘an Mountains Measuring seasonal dynamics of leaf area index in a mixed conifer-broadleaved forest with direct and indirect methods Leaf Area Index Estimated with Plant Canopy Analyzer in Apple Orchards and Analysis of Its Reliability Leaf Area Index Estimated with Plant Canopy Analyzer in Apple Orchards and Analysis of Its Reliability Comparison of near-ground ozone concentrations between urban and rural forests Modelling the three dimensional distribution of direct solar radiation in maize canopy