Abstract: Quercus mongolica, Fraxinus rhynchophulla, and Juglans mandshurica forests are the representative forest types in natural secondary forest zone of northeast China. By using digital camera with fish-eye lens, the hemispherical photographs of the three forest types were taken, and the parameters leaf area index, canopy porosity, and illumination factors were analyzed by Gap Light Analyzer. For the leaf area index of the three forest types, there was a similar variation trend, i.e., increased first and decreased then, with the maximum presented in mid-July or August for Q. mongolica and J.mandshurica forests while in mid-August or September for F. rhynchophulla forest. The canopy porosity of the three forest types also had a similar variation trend, but opposite to leaf area index, being decreased first and increased then, with the minimum presented in mid-June, July, August or September. The analysis of variation coefficients of leaf area index, transmitted direct gap light, and transmitted diffuse gap light indicated that the spatial pattern of leaf area index in July-September was the main factor affecting the spatial distribution of transmitted diffuse gap light. Leaf area index had an exponential regression relationship with canopy porosity.

Key words: Winter wheat, Small amount precision seeding, Yield, Tiller, Physiological function, Metabolism activity, Spike per plant