Lesson 11 spacer Contract Specifications
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Lesson 11

Lesson Objectives

Contract Specifications

Recommended Contract Topics

Lesson 12
Appendix 1
Appendix 2
Appendix 3
Appendix 4
Appendix 5
Appendix 6
Appendix 7
Appendix 8
Appendix 9
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Lesson Objectives

Consider recommended contract specifications and topics.

Contract Specifications

For surveys using the growth intercept or site index curve methods, the following are recommended contract specifications (Figure 11.1):

  • Height: record height to the nearest 10 cm with a maximum error of 5%
  • Age: record age to the exact year with
    • no error on trees <10 years
    • maximum 1 year error on trees 10-20 years
    • maximum 5% error on trees >20 years.
  • It may be difficult to meet these age standards under some field conditions, so flexibility in checking will be required.
  • Species: NO error is acceptable.

Some recommended contract specificationsSome recommended contract specifications
Some recommended contract specifications

Figure 11.1. Some recommended contract specifications.

In some contracts, it is possible (and useful) to specify the method that should be used to estimate site index. When SI is determined with the growth intercept or site index curve methods, specify the number of plots required.

Recommended Contract Topics

Contract administrators should consider the following topics when developing or implementing contracts:

  • recommend that surveyors take this course
  • review SI estimation procedures with the contractor at the viewing and again at the pre-work
  • ensure surveyors attain first few ages by drilling or cutting to calibrate their eye prior to whorl counting
  • consider flagging sample trees as a contract clause.

Provide surveyors with the necessary SI materials:

  • SIBEC guide
  • GI FS415s and manual
  • SI curves
  • Decision key
  • SI/Site class conversion tables
  • SI species conversion tables.

Contract administrators should be prepared to do a GI plot in the field with surveyors.

Tips on how to check a GI survey are provided in Appendix 7.

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