National forest inventories are supposed to provide data for estimating forest resources over large areas (≥ counties). Such inventory systems typically rely on field plots systematically distributed over the whole nation, producing unbiased mean numbers for timber volume and biomass. However, because of the low sapling intensity yielded by such a system (

A cost effective way to improve the national forest inventory is to utilize airborne laser technology. Previously, airborne laser scanners have only been used to collect wall-to-wall data for areas up to 900 km2, but this technology can also be applied in sampling that allows for larger areas to be covered per flying hour. The sampling is carried out by collecting laser data along strips with certain inter distances according to desired sampling rate.

The laser profiling technology has already been applied for large area assessment of timber volume and above ground biomass by strip sampling. Ross Nelson of NASA developed the low-cost Portable Airborne Laser System (PALS) and used it for getting volume and biomass estimates for the entire state of Delaware. Opposed to the laser systems used in wall-to-wall inventories which are scanning lasers, the PALS is a profiling system emitting its laser pulses in a narrow strip along the flight path. The PALS collects significantly less data compared to a scanning system that have swath widths of, say, 500 meters.

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Forest surveying in the field, Engerdal, Hedmark county, Norway. Photo: Ole Martin Bollandsås

Main goal

In this project, the goal is to develop and test a cost-efficient method for measurement, inventory and monitoring of timber resources and biomass/carbon stocks at regional and national levels using airborne laser data.


  1. To develop a method for inventory and monitoring of timber resources and biomass/carbon stocks based on commercially available airborne laser scanner data.
  2. To test and compare the accuracy and costs of the laser scanner-based method (sub-goal 1) with:
  • A method developed by NASA for regional inventories using a low-cost profiling laser.
  • The present system of the National Forest Inventory using field data only.

Project title

Developing and testing a national system for inventory of timber resources and biomass/carbon stocks combining airborne laser and field data (2005-2009).

Funded by

The project is founde by:

  • the Research Council of Norway
  • The Norwegian University of Life Sciences (UMB)
  • NASA
  • Blom Geomatics AS

Related posts/publications

Lomnessjøen and Storsjøen, Hedmark county, Norway. Photo: Ole Martin Bollandsås