Relative density of United States forests has shifted to higher levels over last two decades with important implications for future dynamics.

ABSTRACT: Tree size-density dynamics can inform key trends in forest productivity along with opportunities to increase ecosystem resiliency. Here, we employ a novel approach to estimate the relative density (RD, range 0-1) of any given forest based on its current size-density relationship compared to a hypothetical maximum using the coterminous US national forest inventory between 1999 and 2020. The analysis suggests a static forest land area in the US with less tree abundance but greatly increased timber volume and tree biomass. Coupled with these resource trends, an increase in RD was identified with 90% of US forest land now reaching a biologically-relevant threshold of canopy closure and/or self-thinning induced mortality (RD > 0.3), particularly in areas prone to future drought conditions (e.g.

SUBMITTER: Woodall CW 

PROVIDER: S-EPMC8458300 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature