Quality Index Developed for Northern Red Oak Logs Based Upon Green Lumber Yields

The Quality Index is a timber measure that dates to the 1940s. It is a single number that expresses the relative value of a log as determined by the value of different grades of 4/4 lumber that can be sawn from it. A great deal of research on Quality Indexes was conducted by the US Forest Service in the 1960s and 1970s as part of its Hardwood Improvement Project.

The Quality Index has many applications. One is its ability to place an objective value on a factory grade hardwood log based upon its predicted lumber grade yields (the factory grade designation means the log will be sawn into lumber). Secondly, when utilized in conjunction with Tree Value Conversion Standards, a conversion return for hardwood sawtimber can be realized. Ultimately, the Quality Index can applied as part of a financial maturity assessment of individual hardwood trees or stands.

We initiated research last winter to develop Quality Indexes for oak logs. Our recently completed Quality Index for Northern Red Oak (Quercus rubra) was created by simulating green lumber board foot yields from a range of logs, which varied by diameter, length, and scaling defect. We assumed the log was sawn entirely into 4/4 lumber. By considering green 4/4 lumber as our finished product, we were able to isolate the drying process (and any subsequent changes in product value) from our simulation. Grading criteria followed the US Forest Service’s log grading rules. The model used to predict green lumber yields was also originally developed by the US Forest Service.

You can find the Northern Red Oak Quality Index on the Publications page of our website. A presentation on its background and use accompanies the index tables. Two indexes are provided for Northern Red Oak logs. One is for the southern Appalachian region, and one is for the southern US. These regions follow lumber market areas developed by the Hardwood Review. Please feel free to contact me should you desire further information on the Quality Index, eric_mcconnell@ncsu.edu.