Forest Practices Code, Province of B.C.

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This Forest Practices Code Guidebook is presented for information only

It is not cited in regulation. The Forest and Range Practices Act and its regulations took effect on Jan. 31, 2004. This replaced the Forest Practices Code of British Columbia Act and regulations. For further information please see the Forest and Range Practices Act.

Defoliator Management Guidebook

October 1995


Authority

Forest Practices Code of British Columbia Act
Operational Planning Regulation
Silviculture Practices Regulation

Table of Contents

Introduction

Biology and identification

Distribution of major defoliators

Management principles for defoliators

Landscape and stand level hazard and risk assessment
Tree and stand impact

Detection and predictive sampling

Detection
Aerial surveys
Walkthroughs
Predictive and population sampling
Predictive sampling
Population sampling

Management strategies and treatment options

Douglas-fir tussock moth
Population dynamics
Predictive sampling techniques and population monitoring
Long-term strategies
Short-term strategies
Virus (NPV) application
Western spruce budworm
Population dynamics
Predictive sampling techniques and population monitoring
Long-term strategies
Short-term strategies: biological and chemical control
Western hemlock looper
Population dynamics and detection
Predictive sampling techniques
Long-term strategies
Short-term strategies
Eastern spruce budworm
Population dynamics
Population monitoring and predictive sampling techniques
Long-term strategies
Western blackheaded budworm
Population dynamics and impact
Detection, population monitoring, and predictive sampling
Long-term strategies
Short-term strategies

Glossary

References

General
Douglas-fir tussock moth
Western spruce budworm
Western hemlock looper
Eastern spruce budworm
Western blackheaded budworm

Tables

  1. Common forest insect defoliators and their hosts in B.C.
  2. Occurrence of life stages of insect defoliators
  3. Description and illustration of life stages of five defoliating insects
  4. Detection criteria and symptoms for the major defoliators at stand and tree level
  5. Defoliation intensity ratings for aerial survey mapping
  6. Recommended and possible time frames for predictive and population sampling of the five defoliators
  7. Comparison between foliage protection and population reduction strategies for direct control of forest defoliators
  8. Pre-harvest and post-harvest prescription strategies and treatments
  9. Parameters influencing hazard for Douglas-fir tussock moth
  10. Preferred treatment options for the Douglas-fir tussock moth at different stages in its outbreak cycle.
  11. The schedule of events to detect, monitor, and manage Douglas-fir tussock moth
  12. Product information on registered virus formulations available for use on the Douglas-fir tussock moth
  13. Parameters influencing hazard for western spruce budworm
  14. Average percent loss in the first decade of a 20-year projection in total volume (volume of all trees, between stump and 10 cm top diameter) and harvest volume (volume of logs from trees with a dbh of 30 cm or greater) in interior B.C. after a simulated 7-year western spruce budworm infestation
  15. Description of larval instars of the western spruce budworm
  16. Application specifications and timing for B.t.k application
  17. Recommended number of sample trees needed to determine spray efficacy in a range of block sizes
  18. The schedule of events to detect, monitor, and manage western spruce budworm
  19. Parameters influencing hazard for western hemlock looper
  20. Parameters influencing hazard for eastern spruce budworm
  21. Interpretation of eastern spruce budworm current defoliation
  22. Old defoliation/damage rating for the eastern spruce budworm
  23. Tree vigor rating based on occular assessment for eastern spruce budworm
  24. Interpretation of eastern spruce budworm egg mass densities
  25. Calculation of total rating factor for eastern spruce budworm
  26. Parameters influencing hazard for western blackheaded budworm
  27. Predicted defoliation levels for the western blackheaded budworm based on the numbers of eggs per branch

Figures

  1. Douglas-fir tussock moth defoliation history for B.C. 19161994
  2. Western spruce budworm risk analysis for B.C. 19091992
  3. Western hemlock looper frequency analysis for B.C. 19111994
  4. Eastern spruce budworm history for B.C. 19561994
  5. Blackheaded budworm defoliation history for B.C. 19161994
  6. Defoliator management process
  7. Whole tree defoliation classes by percent crown totally defoliated, with inset showing close-up of branch tip
  8. Fettes scale of defoliation for current year foliage
  9. Illustration of the relative abundance of insects during the four phases of a defoliator cycle
  10. Douglas-fir tussock moth egg mass survey tally card with an example of a sequential survey and calculations
  11. Western spruce budworm egg mass sampling field form
  12. Western spruce budworm larval sampling field form
  13. Application of the population reduction and foliage protection strategies given the prediction of high budworm population levels in the coming year
  14. Decision-making process in multi-layered stands for doing predictive sampling surveys
  15. Decision-making process for treatments in a multi-layered stand with only current year defoliation
  16. Decision-making process for treatments in a multi-layered stand with 2 years defoliation
  17. Decision-making process for treatments in a multi-layered stand with >2 years defoliation
  18. Criteria for treatment of eastern spruce budworm

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