Design of Field Trials for Evaluation of Antisapstain Products
F W Frazer, N R Edmonds, B J Nairn
Field trialing is an important phase of antisapstain product development and careful planning is required to ensure trial validity for predicting performance in the industrial situation.
Experiences of trialing antisapstain products on lumber over a ten-year period are discussed in this paper.
It is not mandatory to source "fresh " wood for trialing and useful information can be generated even if the wood shows visible signs of pre-infection. Measurement of uptake of preservative working solution is recommended, as uptakes can differ considerably between preservatives. Also, continuing wood drying after sawing can cause treatment uptakes to progressively increase over the trial duration.
Strong moisture gradients develop in treated packets during storage and the moisture profile is a particularly important determinant of the development of the various fungal infections. The period and method of assessment should be appropriate to demonstrate differences between products that would be reflected in sawmill practice.