Resi Forest Industry Assessment Tool

Australian forest industry embraces the IML PD-Series Resi.

The IML ( PD-series power drill instrument, commonly called “Resi”, has undergone significant evaluation over the past five years for operational use. The tool can rapidly and quantitatively measure basic density and stiffness in plantation-grown softwoods and hardwoods at low-cost.

Multiple mill trials have favourably compared Resi measurements taken from trees prior to harvest with the quality of actual sawn board product exiting the sawmill.

Non-destructive assessment of wood quality in standing trees has been a research focus of commercial forestry for the past three decades. Resistance drilling has been part of this, with steady technological improvements over time enhancing the accuracy and operational robustness of the technology. The advantage of Resi to commercial forestry lies in low cost, rapid analysis with acceptable accuracy and precision. A single operator can sample in the order of 500+ trees per day, generating a large amount of quantitative data very quickly (Fig. 1).

Each tree is represented by a radial trace of resistance (torque) measurements at a 0.1mm sampling interval, taking less than 30 secs to collect. Resistance correlates strongly with wood basic density (Fig. 2). The difference in the anatomy of the trees indicates that the relationship can differ slightly between species and resistance values need to be calibrated by species. Better understanding the physical interactions between wood properties and Resi sampling conditions is a subject of current study.

Generating so much data so quickly raises the need for customised analysis software to extract the various metrics of commercial interest.

Tasmanian-based Forest Quality Pty Ltd, supported by industry partners and Forest and Wood Products Australia (www., has developed web-based analysis software (Fig. 3) to process the large numbers of Resi traces quickly and efficiently. Batches of traces (up to 1500 at a time) can be uploaded, processed and summarised. Various degrees of user interaction are possible to correct or modify individual trace processing as required.

Resi is rapidly gaining traction as a routine forest industry assessment tool allowing for growers and processors to better understand the quality of the forest and how they can be better managed to enhance their value.

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