Fig. 6: Maximum size-density relationship for an example stand-type.
From: Over half of western United States' most abundant tree species in decline
Individual points represent observed stand-level indices of tree density (N) and average tree size (\(\overline{S}\)). Maximum tree density (\({N}_{\max }\)) is modeled as a power function of average tree size within a stand. Here, we use quantile regression to estimate \({N}_{\max }\) as the 99th percentile of N conditional on \(\overline{S}\). The resulting maximum size-density curve can then be used to compute the relative density of observed stands (RD), where relative density is defined as ratio of observed tree density (N) to maximum theoretical density (\({N}_{\max }\)), given \(\overline{S}\). Source data are provided as a Source Data file.
