Predicting Carbon Accumulation in Temperate Forests of Ontario, Canada Using a LiDAR-Initialized Growth-and-Yield Model

• Published in: Remote sensing (Basel, Switzerland) Switzerland), 2020-01, Vol.12 (1), p.201
• Main Authors: Marczak, Paulina T., Van Ewijk, Karin Y., Treitz, Paul M., Scott, Neal A., Robinson, Donald C.E.
• Format: Article
• Language: English
• Subjects: Abundance; Accumulation; Accuracy; Biomass; Carbon; carbon accumulation; carbon stock; Climate change; Diameters; Equivalence; Estimates; Forestry research; Forests; fvsontario; Geographical distribution; Global warming; growth-and-yield; Lasers; Lidar; Mixed forests; Model testing; Predictions; Remote sensing; Remote sensing systems; Species; Statistical analysis; Statistics; Stems; Temperate forests; Trees; Variables
• ISSN: 2072-4292; 2072-4292
• DOI: 10.3390/rs12010201

Climate warming has led to an urgent need for improved estimates of carbon accumulation in uneven-aged, mixed temperate forests, where high uncertainty remains. We investigated the feasibility of using LiDAR-derived forest attributes to initialize a growth and yield (G&Y) model in complex stands at the Petawawa Research Forest (PRF) in eastern Ontario, Canada; i.e., can G&Y models based on LiDAR provide accurate predictions of aboveground carbon accumulation in complex forests compared to traditional inventory-based estimates? Applying a local G&Y model, we forecasted aboveground carbon stock (tons/ha) and accumulation (tons/ha/yr) using recurring plot measurements from 2012–2016, FVS1. We applied statistical predictors derived from LiDAR to predict stem density (SD), stem diameter distribution (SDD), and basal area distribution (BA_dist). These data, along with measured species abundance, were used to initialize a second model (FVS2). A third model was tested using LiDAR-initialized tree lists and photo-interpreted estimates of species abundance (i.e., FVS3). The carbon stock projections for 2016 from the inventory-based G&Y model) were equivalent to validation carbon stocks measured in 2016 at all size-class levels (p < 0.05), while LiDAR-based G&Y models were not. None of the models were equivalent to validation data for accumulation (p > 0.05). At the plot level, LiDAR-based predictions of carbon accumulation over a nine-year period did not differ when using either inventory or photo-interpreted species (p < 0.05). Using a constant mortality rate, we also found statistical equivalency of inventory and photo-interpreted accumulation models for all size classes ≥17 cm. These results suggest that more precise information is needed on tree characteristics than we could derive from LiDAR, but that plot-level species information is not as critical for predictions of carbon accumulation in mixed-species forests. Further work is needed on the use of LiDAR to quantify stand properties before this technique can be used to replace recurring plot measurements to quantify carbon accumulation.