Ministry of Forests and Range Remote Sensing and Geo-Spatial Applications

Ortho-Photo Mountain Pine Beetle Attack Mapping

The Ministry of Forests and Range (MOFR) has recently completed a project mapping 2005 Mountain Pine Beetle (MPB) red/grey-attack derived from ortho-rectified aerial photography over a large portion of the province. The purpose was to create a visually interpreted classification of the percentage of crown area (number of trees) attacked by MPB within each forest cover polygon. This includes both red attack and grey attack where it could be identified. This page describes the methodology and presents an overview of the results which are available through the MOFR contact person.

Methodology

Colour enhanced 1:20,000 orthorectified aerial photographs were acquired and scanned in the summer of 2005 and were used for interpretation. A vector “pine mask” extracted from the existing VRI database, was used as the base starting point for interpretation. The method involved manual photo interpretation and classification of each VRI polygon for each map sheet, covering a total of 727 mapsheets. Each polygon in the “pine mask” was interpreted into one of four severity codes based on the interpretation of the number of trees (essentially crown extent expressed as a percent) that were identified as being in the red attack phase and/or the grey attack phase of MPB infestation. The codes for red attack and grey attack were assigned based on the following table:

SEVERITY RATING	PERCENTAGE OF TREES ATTACKED	SEVERITY CODE
None to Trace *	Less than 10%	T
Moderate	11% to 30%	M
Severe	31% to 50%	S
Very Severe	Greater than 50%	V

* Light (1%-10%) and Trace (< 1%) classes from the Aerial Overview Survey were merged together into one class.

Results

The results from this project are presented in the figures below. Figure 1 shows the overall extent of orthorectified photographs acquired in 2005 in the province. Click on the link to view full resolution. The results from this project are presented in the figures below. Figure 1 shows the overall extent of orthorectified photographs acquired in 2005 in the province. Click on the link to view full resolution.

Figure 1

Figures 2a. b.c. and d. present the results at the map sheet level. while 2c shows each pine polygon from the VRI colour-coded based on red attack severity class and 2d presents the legend describing each severity class.

	Figure 2a shows the orthorectified aerial photograph in mapsheet 93f.017
	Figure 2b shows the VRI pine polygons on top of the same orthophoto.
	Figure 2c shows each pine polygon from the VRI colour-coded based on red attack severity class The legend above describes each severity class.

For more information, contact Ann Morrison