Lesson 2 spacer Introduction to Site Index
Lesson 1
Lesson 2

Lesson Objectives

What is Site Index

Where is SI Used?

Site Index in Forest Cover Labels

Problems with Incorrect Site Index Determinations

When/Where is SI Recorded?

FPC and SI

SI Source Codes

Biased Site Index and Stands Growing Below Potential

Site Index and Yield

Tree Growth Response to Improved Site Quality

Lesson 3
Lesson 4
Lesson 5
Lesson 6
Lesson 7
Lesson 8
Lesson 9
Lesson 10
Lesson 11
Lesson 12
Appendix 1
Appendix 2
Appendix 3
Appendix 4
Appendix 5
Appendix 6
Appendix 7
Appendix 8
Appendix 9
Course Homepage

Problems with Incorrect Site Index Determinations

It is important to correctly estimate SI. Incorrect SI estimates can lead to a variety of problems, including:

  • inappropriate silviculture prescriptions
  • inability to accurately schedule and plan for future treatments (as required under SMPs)
  • inability to prioritize treatment dollars to the best sites
  • incorrect estimates of the growth potential of regenerated stands
  • incorrect information in the silviculture and inventory databases
  • inaccuracies in the timber supply analysis.

When/Where is SI Recorded?

Site index should be recorded on silviculture prescriptions (SP) and stand management prescriptions (SMP).

SI must be recorded on all legally required silviculture surveys (e.g.,stocking and free growing surveys). All small business, FRBC and government funded silviculture surveys (including I/O and M/O) should provide SI.

SI is required on all MLSIS form C submissions (Figure 2.8). It is required for all ISIS forest cover screen updates (Figure 2.9). SI is required on the FS 810A (Inventory Forest Cover Attribute Form).

FPC and SI

SI is a requirement under the Forest Practices Code. SI is required in both the inventory and silviculture labels in regeneration and free growing survey reports (Silviculture Practices Regulation 25(b) viii and 28(1)(c)). If these labels have different leading species, two unique SI values are required for the stratum. SI is required (Silviculture Practices Regulation 26(1)(b)(4)) in the survey report that must follow intermediate harvest (e.g., commercial thinning).


Figure 2.8. MLSIS form C (click on above image to see a full screen version of the form).

ISIS forest cover report

Figure 2.9. ISIS forest cover report (click on above image to see a full screen version of the form).


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