Forest aboveground biomass mapping and estimation across multiple spatial scales using model-based inference

Article history: Received 14 April 2016 Received in revised form 29 June 2016 Accepted 16 July 2016 Available online xxxx Remotely sensed data have beenwidely used in recent years for mapping and estimating biomass. However, the characterization of the uncertainty of mapped or estimated biomass in previous studies was either based on adhoc approaches (e.g., usingmodel fitting statistics such rootmean square errors derived frompurposive samples) or mostly limited to the analysis of mean biomass for the whole study area. This study proposed a novel uncertainty analysismethod that can characterize biomass uncertainty acrossmultiple spatial scales andmultiple spatial resolutions. The uncertainty analysis method built on model-based inference and can propagate errors from trees to field plots, individual pixels, and small areas or large regions that consist of multiple pixels (up to all pixels within a study area). We developed and tested this method over northern Minnesota forest areas of approximately 69,508 km via a unique combination of several datasets for biomass mapping and estimation: wall-to-wall airborne lidar data, national forest inventory (NFI) plots, and destructive measurements of tree aboveground biomass (AGB). We found that the pixel-level AGB prediction error is dominated by lidar-based AGB model residual errors when the spatial resolution is near 380 m or finer and by model parameter estimate errorswhen the spatial resolution is coarser.We also found that the relative error of AGB predicted from lidar can be reduced to approximately 11% (ormean 5.1Mg/ha;max 43.6Mg/ha) at one-hectare scale (or at 100m spatial resolution) over our study area. Because our uncertainty analysis method uses model-based inference and does not require probability samples of field plots, our methodology has potential applications worldwide, especially over tropics and developing countries where NFI systems are not well-established. © 2016 Elsevier Inc. All rights reserved.