IS 2455:1990 is the Indian Standard (BIS) for method of sampling of model trees and logs and their conversion for timber testing. This standard lays down the methodology for selecting, felling, and sampling model trees from forests. It details the procedures for marking, cross-cutting into logs, and their systematic conversion into standard-sized sticks to prepare small clear specimens for physical and mechanical timber testing.
Method of sampling of model trees and logs and their conversion for timber testing
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Number of Sample Trees per Species | 5 model trees per locality. | Varies with statistical needs; can be 5 to 50+ trees. | ASTM D5536 |
| Standard Bolt Length for Conversion | 2.4 metres | Typically 1.2 m to 1.8 m (4 to 6 ft). | ASTM D5536 |
| Log Conversion Sawing Pattern | Mandatory, specified 'butterfly' diagram. | Recommended principles (e.g., quartersawing), no mandatory diagram. | ISO 3129 |
| Initial Test Stick Cross-Section | 6.25 x 6.25 cm | Sized to yield 50 mm specimens (e.g., 65 x 65 mm). | ISO 3129 |
| Final Primary Specimen Cross-Section | 50 x 50 mm | 50 x 50 mm | ISO 3129 |
| Marking of Bolts from Butt Log | A, B, C, D, etc., from the butt end upwards. | Letters for bolts (A, B, C...) and numbers for cardinal directions (1, 2, 3, 4). | ASTM D5536 |
| Inclusion of Pith | Pith is generally excluded from the final test specimen. | Pith and adjacent juvenile wood are excluded from final specimens. | ISO 3129 |