Research objectives

The principal objective is to develop techniques to give greater certainty to estimates of carbon stored in woody vegetation, for both project scale and national scale carbon accounting. This will be achieved through:

• Improving techniques for quantifying carbon pools and fluxes in woody biomass occurring below and aboveground in a range of Australian ecosystems.
• Accounting for spatial variation in the carbon stored in the root systems of woody vegetation by developing "rules" to account for factors (age, environment, species, management) which alter the root:shoot ratio.
• Providing input into, and develop partnerships with, soil carbon, modelling and remote sensing groups to continually improve spatial and temporal estimates of terrestrial carbon stocks and fluxes.

Relevance

• the impact of changes in land usage, management or climate on terrestrial carbon pools and fluxes can be assessed.
• Cost effective estimates of carbon sequestration rates in reforestation/revegetation can be made to underpin potential trading of carbon credits.

Up to half the carbon sequestered in woody biomass can be stored belowground in roots. Measuring belowground biomass is, however both time consuming and laborious. The absence of suitable sampling methods for roots of woody vegetation has hampered our understanding of the factors that determine belowground allocation. This limits the ability to estimate carbon stored in woody biomass.

Outputs

• Improved estimates of tree root biomass through improved sampling methodologies and strategies.
• Improved estimates of above-ground biomass through improved sampling methodologies and strategies.
• Better spatial estimates of below-ground biomass through an enhanced understanding of factors controlling root:shoot ratios.
• Reliable estimates of decay rates of harvest residues (roots and aboveground debris).
• An initial assessment of the potential of a number of remote sensing platforms to estimate above-ground biomass.
• Provide a series of ground data for major woody ecosystems for model validation and ground-truthing of remote sensing.

Outcomes

The principal outcome will be greater certainty in estimates of carbon stored in woody vegetation for both project scale and national scale carbon accounting.

A2.1

Techniques & sampling strategies for estimating root biomass

The objectives of this sub-project are to:

• Compare alternative root sampling strategies and determine the optimum techniques and sampling design.
• Investigate new techniques for measuring the biomass of root system (Ground Probing Radar).

Detailed root sampling, to characterise horizontal and vertical root distributions, is being undertaken to develop optimum sampling strategy(s) which can be applied in future root sampling in WA, NSW and Qld studies. Data from these intensive studies will allow simulation and comparison of alternative sampling strategies.Ground Probing Radar (GPR) has the potential to provide a new tool for the non-destructive sampling of coarse root biomass. However, there is considerable development work required before GPR can be used for estimating root biomass. Controlled studies are required to examine issues such as resolution, hardware configuration and data processing.

A2.2:

Tree biomass partitioning: environmental, species & management variation

The objectives of this sub-project are to:

• Develop "rules" to account for factors (age, environment, species, management) which alter the carbon stored in the root systems of woody vegetation.
• Continue improvement of techniques for estimating above-ground biomass.

A series of studies are proposed in woodlands, native forests and plantations. Initial work will focus on experimental sites where resources have been manipulated (e.g. nutrition, water, spacing, species). Understanding from such studies would then be incorporated into spatial stand models. The experimental phase will then change to testing the predictive power of such models across landscapes.

A2.3

Decay of harvest residues remaining on site

Knowledge of decay rates of tree parts left after harvest is essential for carbon accounting in forests subject to harvest.

This study aims to characterise the decay rates of slash (remaining above-ground biomass) and roots following harvesting of common afforestation species in WA (Pinus pinaster and P. radiata). Both sites subject to partial harvest (thinning) and complete harvest (clearfelling) will be studied.

A2.4

Remote Sensing of Forest and Woodland Biomass

The objective of this sub-project is to:

• Develop and evaluate the potential of remote sensing technologies for providing spatial estimates of above-ground carbon at project and regional scales.

Two main study areas have been established for this project. These areas are now used to calibrate and validate other more coarse optical and active systems (eg. Radar, Landsat TM) using ultra-high resolution airborne camera and Lidar systems to sample the forests intensively.

Where are the field sites?

Two main study areas have been established. Woodland and forest areas have been sampled in a 220,000ha study site near Injune, within the southern Brigalow Belt of central Queensland. At this site, sampling and mapping approaches at a range of scales have been developed using a wide range of datasets, for assessment and monitoring of extensive woodland areas.

In the Hunter region in New South Wales, a high resolution, operational scale mapping project in commercial forests was undertaken in two NSW State Forest areas, (Olney and Ourimbah) which total approx 400ha. Here radar, lidar and hyperspectral data were gathered to assess the feasiblily of using these types of data on wetter and denser coastal eucalypt forests.

Read more detailed information on
estimating forest and woodland biomass
using REMOTE SENSING