24 black and white and colour slides labelled "Decay Detection" showing instruments used. 1 dated '95. Some labelled D. Johnstone. 1. Shigometer. 2. Resistograph. 3. Fractometer. 4.Device (Arborsonic Tester). 5. Plug. 6. Quadrant. 7.Metriguard. 8.Fractometer. 17. Tyromyces. 22. Eucalypt. 23. Ganodderma. 24. Poplar '95 Formes.decay detection, instruments, d. johnstone, trees, arboriculture, shigometer, resistograph, arborsonic tester, quadrant, metriguard, fractometer, tyromyces, ganodderma, poplar 95 formes