Forest Resources - Snapshot of Key Findings

Satellite remote sensing of canopy change

Hislop S, Stone C, Gibson RK, Roff A, Choat B, Nolan R, Nguyen TH and Carnegie AJ. (2023) Using dense Sentinel-2 time series to explore combined fire and drought impacts in eucalypt forests, Front. For. Glob. Change, 6: 1018936.

Time series analysis using satellite data to map the extent and severity - and recovery from - the 2019 severe drought and 2019-2020 Black Summer wildfires.
In New South Wales, 5.8 million ha were affected by fire and 5.0 million ha by drought. Following substantial rain, much of this area showed substantial recovery, except those areas that had a combined impact of drought (2019) and fire (2019-2020).
These methods are easily transferrable and demonstrate an approach for monitoring forest disturbance at higher temporal and spatial scales than those typically used.

Gibson, RK, White LA, Hislop S, Nolan RH and Dorrough J. (2022) The post-fire severity index; a new approach to monitoring post-fire recovery by satellite imagery, Remote Sensing of Environment 280: 113151.

The post-fire stability index measures forest recovery by examining the rate of change in the years after fire.
The method is based on the concept that a disturbed system state will be reflected by increasing or decreasing rates of system change, while undisturbed or recovered system states are characterised by near-zero rates of change.
The index was found to be a more reliable indicator of post-fire recovery compared with methods based on pre-fire baselines.
Maps of forest recovery based on the post-fire stability index complement fire severity maps, which are now routinely produced.

Hislop S, Haywood A, Alaibakhsh M, Nguyen TH, Soto-Berelov M, Jones S and Stone C. (2021) A reference data framework for the application of satellite time series to monitor forest disturbance, Int. J. Appl. Earth Obs. Geoinf., 105: 102636.

Three decades of Landsat satellite imagery was examined to explore large impact disturbances, such as fire and drought, in eastern NSW forests.
The reference data provides robust estimates of forest disturbances over time, including information on type, frequency, magnitude and associated recovery rates.
Forest disturbances, particularly in relation to fire and drought, were found to be a common occurrence in NSW forests, with 70% of forests having had at least one major disturbance in the last 33 years and 35% having had two or more disturbances.

Stone C and Hislop S (Editors). (2022) Characterising native forest structure from co-incident terrestrial and airborne LiDAR, FWPA Final Report PNC546-2021, 56pp.

A key mechanism for demonstrating sustainable management of native forests is the monitoring of changes in forest structure.
Airborne lidar scanning (ALS) and mobile laser scanning (MLS) 3D point cloud data were acquired in six native eucalypt forests.
For several tree- and plot-level attributes, both the ALS and MLS point cloud provided higher accuracies than manual measurement, even in the presence of understorey vegetation.
The MLS tree- and plot-level metrics have potential to be used as reference data for larger scale spatial modelling.