Ecosystem physical structure, defined by the quantity and spatial distribution of biomass, influences a range of ecosystem functions. Remote sensing tools permit the non-destructive characterization of canopy and root features, potentially providing opportunities to link above-and belowground structure at fine spatial resolution in functionally meaningful ways. To test this possibility, we employed ground-based portable canopy LiDAR (PCL) and ground penetrating radar (GPR) along co-located transects in forested sites spanning multiple stages of ecosystem development and, consequently, of structural complexity. We examined canopy and root structural data for coherence (i.e., correlation in the frequency of spatial variation) at multiple spatial scales ≤10 m within each site using wavelet analysis. Forest sites varied substantially in vertical canopy and root structure, with leaf area index and root mass more becoming even vertically as forests aged. In all sites, above-and belowground structure, characterized as mean maximum canopy height and root mass, exhibited significant coherence at a scale of 3.5-4 m, and results suggest that the scale of coherence may increase with stand age. Our findings demonstrate that canopy and root structure are linked at characteristic spatial scales, which provides the basis to optimize scales of observation. Our study highlights the potential, and limitations, for fusing LiDAR and radar technologies to quantitatively couple above-and belowground ecosystem structure.Keywords: canopy; root; biomass; spatial wavelet coherence; radar; LiDAR
Highlights
•Canopy and root biomass are examined across a forest chronosequence.• Colocated ground-based LiDAR and ground-penetrating radar data were collected.• Spatial wavelet analysis reveals coherence in canopy height and root biomass.
•All ages exhibited coherence between canopy and root structures at a scale of 3-4 m; oldest stands demonstrated coherence at 8 m.
•We demonstrate methods to quantify fine-scale patterns of root-canopy structure.