Model-assisted estimation of biomass in a LiDAR sample survey in Hedmark County, NorwayThis article is one of a selection of papers from Extending Forest Inventory and Monitoring over Space and Time.

Abstract
Inasmuch as LiDAR is becoming an increasingly prominent tool for forest inventory, it is timely to develop a framework to understand the statistical properties of LiDAR-based estimates. A model-assisted approach to estimation and inference when using LiDAR as a tool to inventory aboveground forest biomass is presented. An empirical example is also presented, yet the article’s focus is largely methodological. The sampling plan in the example is viewed as a two-stage design, with slightly different primary sampling units between the profiling and scanning laser surveys. A regression estimator is presented that uses biomass data from the Norwegian National Forest Inventory as the response variable and laser-derived variables as covariates. A major thrust of this article is the presentation of the variance of the estimators of total biomass and biomass per hectare as well as variance estimators.