ACOUSTIC TOOLS IN FORESTRY: A CASE STUDY IN ITALY

Acoustic tools are a non-destructive method of predicting the physical and mechanical properties of timber and wood-based materials. They work by measuring the propagation of stress waves through wood. Acoustic technologies have been well established as material evaluation tools in the past several decades, and their use has become widely accepted in the forest products industry for online quality control and products grading. Recent research developments on acoustic sensing technology offer further opportunities to evaluate standing trees and logs for general wood quality and intrinsic wood properties. In Italy, the demands for sustainably produced wood as a raw material for a variety of end uses is placing increased pressure on the forest resource. Knowledge of the timber properties of trees and logs is important to ensure that harvested wood is directed to its most appropriate end use. Current harvesting practice in the Italy means that trees are often felled, processed and dried before the timber is strength graded by machines at the sawmill. This process can be inefficient if timber destined for structural uses is later found to be unsuitable; downgrading may incur significant financial and environmental costs. The use of acoustic technology to predict the mechanical properties of timber is a well-established practice overseas. Recent advances in technology and the development of portable instruments mean that wood can now be assessed in standing trees before they are felled. This paper presents in the first part the fundamentals of acoustic wave propagation in trees and logs and in the second part the first results of trials conducted to measurements of acoustic velocity in standing trees and logs. The results demonstrate the possibility of obtaining further opportunities for wood manufacturers and forest owners to evaluate raw wood materials (standing trees, stems, and logs) for general wood quality and intrinsic wood properties. This provides strategic information that can help make economic and environmental management decisions on treatments for individual trees and forest stands, improve thinning and harvesting operations, and efficiently allocate timber resources for optimal utilization. For example, the information could be used to sort and grade trees and logs according to their suitability for structural applications and for a range of fiber properties of interest to paper makers. Another example is to determine the relationships between environmental conditions, silvicultural treatments and wood fiber properties so that the most effective treatment can be selected for future plantations for desired fiber quality.