Readings CGNF vs loss Factors Flashcards
What are the 2 types of CGNF cruising? What is the difference?
- MOFR developed system of deductions based on the VRI process.
- Traditional system where cruiser estimates decay and log grades based on experience knowledge and scaling conventions.
MOFR system is regimented while traditional system leaves final call at discretion of the cruiser.
What are some factors that effect final net volume that are out of a cruisers control?
Sampling error, # of plots, Taper factors, Hidden decay, Bucking and utilization policies.
What is the loss factor system?
A system for determining CP cruise volume and value with complicated algorithms based on decay factors with broad averages designed for large inventory sampling.
Used by the MOFR
What is the CGNF system
Call Grade Net Factor system uses cruisers visual estimations, knowledge and experience combined with scaling conventions to estimate volume and value on a log by log basis.
What are some aspects of the LF system that make it a poor choice compared to the CGNF?
- Relies heavily on broad averages
- very little continuity between cruise data and results
What are some aspects of the CGNF that make it a good choice?
- Results of a CGNF cruise can be directly compared to the cruise data and visual estimations made by the cruiser
- Produces a more realistic and accurate estimate of cruise volume/value
What is call grading?
Estimation of timber quality based on suitability for the manufacture of predetermined finished products and “Call” a predefined quality code.
What is net factoring?
A forest measurement procedure used to estimate the amount of decay and missing wood in standing timber in order to compute the NET volume.
- requires cruiser to estimate % sound wood for each log produced by the call grade procedures.
What are NVAF?
Net volume adjustment factors developed by subsampling to quantify hidden decay and log taper factors. Essential part of VRI required to provide sample data that meets MSRM standards.
What 2 events took place in the mid 20th century that had a major impact on coastal timbercruising?
- The original forest inventory of B.C. (Relied on LF system)
- The advent of cutting permit cruising
When was the CGNF system re-vamped and who did it?
Late 20th century the VRI cruise design team refined the CGNF system and documented to make it more teachable.
Where is CGNF cruising most common?
Coastal BC
Both CGNF and LF reduce gross volume to account for rot and other factors. How do those calcs differ?
CGNF on the coast applies log grades to net volume by log
LF in the interior calculates the lumber recovery factor from the cruise data using complex algorithms to estimate available lumber.
