Title

Bell Miner Associated Dieback (BMAD) Mapping for the Gondwana Rainforests of Australia Border Region 2013

Data Quality Statement

Name: Data Quality Statement

Protocol: WWW:DOWNLOAD-1.0-http--download

Description:

Data quality statement for Bell Miner Associated Dieback (BMAD) Mapping for the Gondwana Rainforests of Australia Border Region 2013

Function: download

Download Package

Name: Download Package

Protocol: WWW:DOWNLOAD-1.0-http--download

Description:

Shapefile Data

Function: download

Code

599abc9f-c6da-4dd6-9587-4d50d112d950

Name

ISO 19115

Edition

2016

Type

vector

Geometric Object Type

complex

Geometric Object Count

1285

Code identifying the spatial reference system

4283

Topic category

Title

ANZLIC Search Words

Reference date

2008-05-16

NSW Place Name

South East Queensland and North East NSW

Coordinate reference system

Authority code

urn:ogc:def:cs:EPSG::

Code identifying the coordinate reference system

5711

End position

N/A

Contact info

Contact position

Data Broker

Organisation name

NSW Department of Climate Change, Energy, the Environment and Water

Telephone number

131555

Email address

data.broker@environment.nsw.gov.au

Web address

https://www.nsw.gov.au/departments-and-agencies/dcceew

Responsible party role

pointOfContact

Lineage

Forest condition classification Prior work by Queensland and NSW NPWS established a framework methodology for forest condition assessment involving of a three point score for each of the lower stratum (0-2 m); mid-stratum (2-6 m) and the canopy, nominally providing 27 possible structural condition combinations, with further sub-classification of canopy condition by the degree and severity of dieback to provide additional combinations. Based on iterative testing and application, it was agreed in conjunction with the project team to modify the assessment framework by removing the sub-classifications, and to note the presence of dead trees as possible indicators of BMAD. Mapping and assessment procedure A structured approach to air photo interpretation (API) was developed and applied to mapping forest structural condition over an area of slightly greater than 100,000 ha. All available photoigray was captured in 2009. Hard copy imagery (approx. 1:30,000) proved unsuitable for useful interpretation. For consistency of format across the region, API was carried out using digital ortho-photography based on multiple cues. First, visible areas of possible BMAD were identified, then reasonably homogenous polygons delineated. Aerial transects sampling 98% of mapped polygons were flown as a means of validating API and to inform amendments to the initial mapping. Aerial transects provided a highly efficient and accurate means of truthing mapped API polygons. A total transect length of 3,218,974 m (3,219 km), corresponding to an effective area of 32,190 ha or around 32% of the project area, was coved in 10 days. Transects were flown at a height above ground level of approximately 120 m. Permanent plots were established by a combination of ground-based assessment and aerial assessment by hovering over the plot location. This allowed otherwise inaccessible areas to be sampled, and more extensive sampling to be carried out than could have been reasonably achieved by ground-based sampling alone. The permanent plots provide benchmark data that can be revisited to monitor changes in vegetation condition over time and/or in response to management interventions. Estimation of polygon score from aerial survey sampling API mapping is the result of averaging condition over a large area. Conversely, aerial survey transects represent a series of short, contiguous, linear plot samples. These approaches represent forest condition at significantly different scales. Notwithstanding, aerial survey transects were used to validate API mapping by calculating the weighted average condition score of transect plots within a polygon. When a weighted average condition score is calculated, it may be definitive (e.g., 90% condition score 3), or marginal (e.g. 33% condition score 1, 33% condition score 2 and 34% condition score 3). To address this issue, and to use weighted average condition score from aerial transect mapping to provide an outcome that is useful from a management perspective, it was agreed with the project team to use aerial transect scores to classify polygons on the following basis:  Use aerial transect data to get an “aerial transect” score for each polygon on the basis that for each layer as follows:  if >30% “3”, then score as 3;  If 30% “2”, then score as 2;  If 30% “1”, then score as 1. The resulting calculated condition score for any polygon was subsequently used to compare with the original the API condition score. Accuracy and mapping correction Accuracy of API mapping relative to the condition score of polygons based on aerial assessment surveys, calculated on a stratum-by-stratum basis and allowing for a tolerance +/1 condition score class, was between 75.9% and 77%. Five error types were identified as reasons for possible discrepancies between API (based on 2009 photography) and aerial transects (carried out in 2013). These were as follows. Only type 4 and 5 errors represent mistakes: 1. The aerial transect is not representative of the mapped polygon (e.g., the aerial survey transect may follow a gully line that is not representative of the overall polygon); 2. The aerial transect does not adequately sample the mapped polygon (e.g., the aerial survey transect may cross the corner of a polygon, providing an inadequate sample to accurate represented the true polygon average canopy conditions; 3. There is a real change in the average canopy condition from the time of aerial photograph capture (2009) and the time of aerial survey (2013); 4. The original API is incorrect; or 5. The aerial survey is incorrect. Following comparison of API and aerial transect results, any polygons differing by greater than one condition score class were marked for review.

Supplemental Information - BMAD Transect Points, BMAD Transect Lines, BMAD Vegetation API Original Polygons, BMAD Vegetation API Bell Miner Damage Polygons, BMAD Permanent Plot Points.

Limitations on public access

Contact position

Data Broker

Organisation name

NSW Department of Climate Change, Energy, the Environment and Water

Telephone number

131555

Email address

data.broker@environment.nsw.gov.au

Web address

https://www.nsw.gov.au/departments-and-agencies/dcceew

Responsible party role

pointOfContact

Contact position

Data Broker

Organisation name

NSW Department of Climate Change, Energy, the Environment and Water

Telephone number

131555

Email address

data.broker@environment.nsw.gov.au

Web address

https://www.nsw.gov.au/departments-and-agencies/dcceew

Responsible party role

pointOfContact