Is Foliage Within Crowns of Cryptomeria japonica More Heterogeneous and Clumpy With Age?

Abstract

Foliage clumping structure is important for forest ecological functions but has not yet been quantitatively analyzed. We examined how foliage clustering within crowns of Cryptomeria japonica changed with age. We sampled 10 trees from four monospecific stands with different ages from 20- to 88-years-old, and measured foliage mass density in cubic cells. Three indices of foliage clumpiness—coefficient of variance, Moran's I for aggregation of foliage density, and cluster fragmentation—correlated with the proportion of foliage gaps. As trees aged, foliage distributed more heterogeneously and clusters fragmented. Clumping in old crowns improves light interception under direct light conditions.

Keywords:

• crowns of Cryptomeria japonica
• foliage clumpiness
• fragmentation of foliage clusters

Acknowledgments

The authors are grateful to the personnel of the Kagoshima University Forest for their support. This study was supported in part by Grants-in-Aid for Scientific Research (Nos. 15580129, 23405024, and 20380088) from the Ministry of Education, Culture, Sports, Science, and Technology, Japan.