2020–21 SLATS Report
Key findings
Statewide overview
- At the start of the 2020–21 SLATS monitoring period, Queensland had 95,677,148 hectares (ha) of woody vegetation with more than 10% crown cover.
- Approximately 7.6 million ha of this woody vegetation is existing regrowth. The remainder is remnant or high-value regrowth woody vegetation.
- In 2020–21, 349,399ha of woody vegetation was affected by clearing activity. This is a 17% decrease in clearing activity from 2019–20 (418,656ha) and a 49% decrease from 2018-19 (680,688ha).
- Of the total clearing activity, 322,515ha (92% of all clearing activity) resulted in full removal of the woody vegetation (i.e. ‘full clearing’). This is a 5% decrease in full clearing from 2019–20. The remaining 26,884ha of clearing activity in 2020–21 was partial clearing.
- In 2020–21, 59,654ha of new regrowth was mapped. It is important to note that most of the state’s existing regrowth is already included in the SLATS woody extent baseline. New regrowth is only mapped if it can be reliably detected using SLATS methods.
- At the end of the 2020–21 SLATS monitoring period, Queensland had 95,414,287ha of woody vegetation. From a starting balance of 95,677,148ha, 322,515ha was subtracted for full clearing and 59,654ha was added for new regrowth. This represents a net reduction of 262,861ha in the extent of the state’s woody vegetation from 2019–20.
Statewide breakdown—clearing activity
- About 15% (54,136ha) of the statewide clearing activity was in Category B (remnant) areas—a 39% decrease from 2019–20 (88,327ha). Just over two-thirds of this Category B clearing activity (70% or 37,888ha) resulted in full removal of the woody vegetation.
- About 1% (4,701ha) of the statewide clearing activity was in Category C (high-value regrowth vegetation), and less than 1% (2,321ha) was in Category R (regrowth watercourse area).
- Clearing activity in Category X areas (i.e. those areas not generally regulated by the Vegetation Management Act 1999) accounted for 82% (288,165ha) of the total clearing activity in Queensland. Most of this resulted in full removal of the woody vegetation (278,884ha or 97% of all Category X clearing activity).
- Less than 1% (2,714ha) of the statewide clearing activity was in areas that have endangered regional ecosystems present and about 3% (10,546ha) was in areas that have of concern regional ecosystems. About 14% (49,850ha) of the clearing activity was in areas that have least concern regional ecosystems present.
- Of the state’s 13 bioregions, the Brigalow Belt (52% or 180,283ha) and Mulga Lands (21% or 72,238ha) accounted for nearly three-quarters (72%) of the state’s woody vegetation clearing activity. In each of these bioregions, over 90% of the clearing activity was mapped as full clearing.
- Clearing activity in the Great Barrier Reef catchment areas accounted for 47% (164,766ha) of the state’s total clearing. This was a 10% decrease in clearing activity from 2019–20 (182,904ha). About 90% (148,507ha) of the clearing in reef catchments resulted in the full removal of the woody vegetation.
- About 89% (310,339ha) of the statewide clearing activity was attributed to the pasture landcover replacement class. Of this, about 96% was full clearing. A further 4% (12,905ha) of the clearing activity was attributed to forestry. The crop (5,156ha) and mine (4,736ha) landcover replacement classes each contributed about 1% of the total clearing activity.
- About 91% (317,866ha) of the total clearing activity occurred in sparse or very sparse woody vegetation (i.e. vegetation with less than 50% crown cover). A further 9% (29,851ha) of the clearing activity occurred in mid-dense vegetation (i.e. 50-80% crown cover).
- Based on estimates of woody vegetation ‘age since disturbance’, about 52% (182,913ha) of the total clearing activity occurred in vegetation estimated to be greater than 15 years old (refer to note). About 36% (125,765ha) of the total clearing occurred in vegetation that was estimated to be less than 15 years old. The remainder (12% or 40,721ha) occurred in woody vegetation where a valid ‘age since disturbance’ estimate could not be determined.
Statewide breakdown—regrowth
- Of the state’s 13 bioregions, the Brigalow Belt bioregion had the greatest area of new regrowth mapped, contributing 39% (23,454ha) to the state’s total. The Southeast Queensland bioregion had the next greatest area of new regrowth mapped, contributing about 20% (12,229ha) to the state’s total.
- About 67% (39,837ha) of the new regrowth mapped was attributed to the pasture landcover class, and about 24% (14,531) attributed to forestry. A further 7% (4,041ha) was mapped as crop, largely due to new tree-crop orchards in parts of Southeast Queensland (Burnett-Mary) and Wet Tropics (around Atherton) bioregions.
- Of the new regrowth mapped, about 80% (47,933ha) was categorised as either sparse or very sparse woody vegetation, and 20% (11,686ha) as mid-dense woody vegetation.
- Of the new regrowth mapped, 70% (41,484ha) was estimated to be less than 15 years old.
Note: Since the release of 2018–19 SLATS report, the methods for estimating the age since disturbance of woody vegetation have been refined and data updated. The estimates are based on time-since-cleared data derived from SLATS clearing histories, and time-series analysis of more than 30 years of Landsat satellite imagery aimed at detecting woody vegetation disturbance and regrowth. The age since disturbance estimates use the time-series information where sufficient evidence is available to assign a valid estimate of how long the woody vegetation has been regrowing following a disturbance event. These updates have resulted in the following for SLATS reporting and published data:
- the 2018–19 SLATS reporting has not been revised and remains as reported
- the updated age since disturbance estimates have been used in the 2019–20 SLATS reporting and this 2020–21 SLATS report
- the age since disturbance spatial data available in QSpatial includes the updated estimates
- the updated age estimates for all monitoring periods have been used in all relevant data files that can be accessed from this 2020–21 SLATS report.
For more information on how the age since disturbance estimates are derived, refer to the SLATS methodology. It is important to note that woody vegetation that is greater than 15 years is not always considered to be remnant or high-value regrowth, as additional criteria such as species composition and vegetation height are used to determine remnant or high-value regrowth status. This is determined by the Queensland Herbarium as part of the regional ecosystem mapping framework.
In this guide: