GEDI Footprint-Level Structural Similarity Index (SSI) Estimates for Brazilian Tropical Forests

This dataset contains footprint-level Structural Similarity Index (SSI) estimates derived from NASA’s Global Ecosystem Dynamics Investigation (GEDI) mission for three tropical forest landscapes in Brazil. SSI is a reference-based metric of forest structural condition that quantifies how closely the three-dimensional structure of a forest stand resembles that of conserved old-growth forests within the same landscape. It integrates multiple GEDI L2A/L2B structural metrics (relative height percentiles, plant area index, foliage height diversity) using a one-class Isolation Forest model trained exclusively on conserved reference forests. The dataset includes SSI values for GEDI footprints (2019 - 2022) in: (i) the Pontal do Paranapanema region in the western Atlantic Forest, used to compare structural condition across land-use and land-cover types (conserved remnants, isolated fragments, restoration plantings, commercial planted forests, and agro‑pastoral land); (ii) the Paragominas region in the southeastern Amazon, used to quantify structural recovery trajectories of secondary forests along a chronosequence; and (iii) the Xingu region in the Amazon–Cerrado transition, used to assess structural degradation and recovery under recurrent fire. For each footprint, the files provide geographic coordinates and the corresponding SSI value (0–1), where higher values indicate greater structural similarity to reference forests. These data support the manuscript “Structural Similarity Index: A Reference-based Approach to Quantify Forest Structural Condition Using Spaceborne LiDAR” and are intended to facilitate reuse of the SSI product for forest degradation and recovery assessment, method intercomparison, and integration with other remote sensing or field-based datasets. Users are encouraged to interpret SSI values within each study landscape, as the index is calibrated to local reference conditions rather than representing a global, absolute measure of structural integrity.