Abstract Stand density indices (SDIs) are surrogate measures of site occupancy useful for developing quantitative management tools for forest types that have not been extensively studied. For example, there has been little research of growth-density relationships for baldcypress (Taxodium distichum [L.] L.C. Rich.). We used published data, forest inventory data, and a 25-year-old thinning study to identify maximum densities and density of incipient self-thinning in baldcypress. Results suggest that a maximum Reineke's SDI is approximately 1,200 (SI units) in baldcypress, which agrees with practical experience and the theoretical limit derived from observed correlations between a species wood density and maximum SDI. Thinning a baldcypress stand to ≥58% of maximum SDI did not affect tree-level or stand-level growth, but thinning to 40% of maximum SDI increased diameter increment and net volume increment (at α = 0.07) in the first 25 years after thinning. These results are consistent with expectations based on stand density-growth relationships for other species, which supports the general utility of management tools based on stand density concepts.