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Method development and LiDAR

The method development for the carbon accounting system within LUCAS focuses principally on:

Diagram showing sequence of data collected from the field (top row) and the modelling steps and analysis to determine allocation of carbon to the four biomass pools.

Diagram showing sequence of data collected from the field (top row) and the modelling
steps and analysis to determine allocation of carbon to the four biomass pools.
The 300 index is a measure of forest productivity.

A first priority was to develop sound techniques for collecting land use data, and then to work out how to calculate the carbon values for each of the five carbon pools. The methodology needs to meet the Good practice guidance by the IPPC.

The results of investigations and method development for each component will be published in independent peer-reviewed journals: this provides transparency and ensures that New Zealand approaches are widely understood.

 

LiDAR

The term LiDAR is short for Light Detection And Ranging; the technique is also known as Laser Scanning. This determines distance to an object or surface using concentrated light pulses. It is an 'airborne mounted technology', that is, it tends to be used from aircraft.

LiDAR uses light waves rather than radio waves, but otherwise it is very similar to radar ('radio detection and ranging'). The range to an object is determined by measuring the time delay between transmission of a pulse and detection of the reflected signal.

 

LiDAR use in New Zealand

The LUCAS team has evaluated the possibility of using LiDAR instead of field plot measurements. This avoids the problem of access to forestry land where owners are uncooperative, or where access is limited or restricted.

Measured tree/forest characteristics using LiDAR can be correlated with concurrent field measurements. The relationships between data can then be applied to plots where only LiDAR measurements are available; LUCAS uses this to determine carbon stock in the above-ground biomass carbon pool.

Actual measurements are well underway and, in combination with field measurements, are contributing to estimates of the total amount of carbon in forestry plots across New Zealand.

Part of a LiDAR image of a Pinus radiata forest near Rotorua.

Part of a LiDAR image of a Pinus
radiata forest near Rotorua. This extract
is 10 m wide and clearly shows the profile of nine
trees. The ground surface shows in blue, and
the tree foliage in light blue through green
and yellow to red. Yellow and red denote the
highest points above the ground surface.
The absence of any lower branches indicates the
forest has been pruned.

Last updated: 3 August 2009