Stand Density Index Estimates Leaf Area Index in Uneven-Aged Ponderosa Pine Stands

Uneven-aged silviculture is increasingly favored where diverse management objectives require complex stand structures. Traditional uneven-aged silvicultural methods have been criticized as inflexible and lacking ecological basis. Stocking indices such as Reineke's stand density index (SDI) are flexible and easy to apply, but are not necessarily ecologically meaningful. We used data from Black Hills ponderosa pine stands to test whether SDI is a suitable proxy for leaf area index (LAI) in uneven-aged stands. LAI has clear ecological meaning, and is interpretable in terms of resource use efficiency and site quality. We found SDI explained almost 90% of the variation in LAI in 21 uneven-aged stands, and was unbiased by tree size. Our results show SDI is a useful tool for regulation of complex stand structures.