Methods

With the CFS's assistance, the MOF has produced a standardized Aerial Overview survey method and digital mapping protocol that was approved by the provincial Resources Inventory Committee (RIC - now the Resource Inventory Standards Committee, RISC) in 1997 and revised and approved in September, 2000. These standards assume that digitizing would be done using an Intergraph Microstation workstation (MOF standard). Attribute information must be saved in an Access 97 database to aid in the roll-up of the provincial data. A blank database is available on the MOF FTP server at:

http://www.for.gov.bc.ca/ftp/hfp/external/!publish/aerial_overview/data_stds/database_template/

Since these standards were written, it became more obvious that most of the digitizing is done using ESRI ArcInfo and the data translated to ArcView format. The digitizing must now use the ArcView Digitizing Standards.

The official species code list is available from the MOFR Integrated Data Dictionary at:

http://www.for.gov.bc.ca/pScripts/isb/idd/ValidationCode.asp?Codename=PEST_SPECIES_CODE

The list has been recently downloaded to an Excel file: Pest Species Code list

The 2006 survey will also include a field to record tree species attacked, particularly for pests that attack multiple species like the mountain pine beetle. The official tree species code list is posted at:

http://www.for.gov.bc.ca/pScripts/isb/idd/ValidationCode.asp?Codename=VEGCAP_SPECIES_CD

RECENT DATA STANDARD REVISION

Since 2004, due to the wide-spread mountain pine beetle outbreak, the aerial overview severity codes were expanded to include two new classes Trace (T) (<1% attack) and Very Severe (V) (>50% attack) with Severe (S) being modified to include 31-50% attack.

Mortality Severity Codes

Severity	Code	Percent of Trees in Polygon With Red Attack
Trace	T	<1% attack
Light	L	1-10% attack
Moderate	M	11-30% attack
Severe	S	31-50% attack
Very Severe	V	>50% attack

No changes were made for the defoliation codes.

Detailed aerial surveys performed mainly for detection of bark beetles should also follow these core digital mapping standards which will simplify summaries within regions and districts. Detailed aerial survey standards are described on the FIA Land-based Investment program site at: http://www.for.gov.bc.ca/hcp/fia/landbase/aerial_detection.htm

Digital data standards for detailed aerial surveys are posted at: http://www.for.gov.bc.ca/hfp/health/fhdata/detailed_digital_stds.htm

Aerial overview surveys are usually performed from fixed-wing aircraft flown at altitudes ranging 500 to 1000m (1500 to 3000 ft.) at speeds of 80 to 90 knots. The survey is designed to cover as much area as possible while retaining the ability to identify and map infested stands at map scales of 1:100,000 to 1:250,000. Overview data only provides sufficient detail to describe gross area damaged, general location of the damage, and, when compared to previous year's data, the trend in damage (increasing, decreasing, or static). The survey is not normally accurate enough to direct operational activities but it is used to identify general areas of interest for directing more detailed detection. On a much smaller area, more accurate aerial data collection is done by forest districts and licensees with rotary or fixed-wing aircraft, often aided with Global Positioning System (GPS) navigation equipment. Some of the regions' bark beetle damage data published in the overview summary table for 1999 and in some years summarized by FIDS were collected using only an operational survey since it was the only source of aerial survey data for that year.

Damaging agents are usually identified through their unique damage characteristics, a prior knowledge of pest activity, and ground survey verification.

MORE INFORMATION ON AERIAL OVERVIEW SURVEY METHODS (data assumptions, accuracy, limits)

Last updated on April 27, 2006
The contact for this web page is: tim.ebata@gov.bc.ca


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