Forest Health Network Archives
Pest Data for British Columbia

[ Introduction Mapsheets Region All of BC or Pests Questions ]

Introduction

This web site contains the Forest Health Network aerial detection survey coverages for British Columbia. These "pest" coverages are stored as an ArcInfo coverage format and are converted to an ArcInfo export file (.e00) format for FTP purposes. The coverages can be selected in three different ways: by mapsheet, by region, or for the whole of BC.

How to retrieve data from this site:

Select a method for retrieval: There a four different ways of finding the desired pest type and year. The methods are by Mapsheet, Region, All of BC, and by pest.

Selecting by mapsheet: A map of BC is displayed showing all of the 1:250,000 mapsheets of BC. Next to the map is a listing of all the mapsheets. You can select by clicking on the mapsheet represented on the BC map or by the mapsheet number located beside the map. If you are looking for a 1:100,000 scale mapsheet, click on the corresponding 1:250,000 scale mapsheet as the larger scale mapsheets can also be found there if they exist.
Selecting by region: A small map of BC displays the Ministry of Forest Regions. The desired region can be selected by clicking on the corresponding region name located to the right of the region map.
Selecting by all of BC: You can select a pest coverage for the whole of BC by selecting the desired pest.
Selecting by pest: Selecting by pest is the same as selecting by all of BC. Each of the other selection methods also allow for pest selection once the initial mapsheet or region has been selected.

Data Description:

Aerial detection surveys are conducted to detect and monitor annual, visible vegetation damage primarily caused by insects. Aerial detection surveys are intended to detect new activity, to monitor the trend of ongoing activity, to provide general location information, and to subjectively rate levels of defoliation. Manually mapping such activity has quantitative and locator accuracy limitations and does not maintain the accuracy standards as most data found in GIS databases.
Briefly, aerial detection pest surveys are generally carried out from fixed wing aircraft where observers manually sketch each infestation site onto 1:100000 or 1:250000 scale basemaps. The observers sketch infestation sites by drawing polygons around the outer perimeter of the infested area on the map. Ground checks and other sampling methods are carried out to evaluate the subjective ratings. Often very small polygons are represented by a single point. Then using visual observations, the observer subjectively, based on many years of past experience, records the defoliation severity or mortality of each polygon. Sketch maps are then digitized using Arc Info.

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