Article Figures & Data
Figures
- Fig. 1
Some defects in trees and related symptoms
- Fig. 2
The Metriguard hammer, sensor and stress wave timer together with the screws ready for detection of decay in trees.
- Fig. 3
Only by use of screws can the punching of wooden fibers be avoided.
- Fig. 4
How to measure the extent of decay inside the tree A) in radial direction. B) in longitudinal direction.
- Fig. 5
Cracked cross sections. A) No drastic reduction in sound velocity when the stress wave is running parallel to the crack. B) Drastically reduced sound velocities when the stress wave has to be deviated around the crack.
- Fig. 6
Drastic reduction of effective sound velocity in a sweet chestnut tree due to multiple decay expanding along the tree rings leading to an ensemble of concentric cracks.
- Fig. 7
Hollow or decayed trees lead to significant reduction in velocity when the defect is large enough. A) Decay in spruce reduces the speed down to 66% of the value for sound wood. B) Hollow beech with only 27% of the normal velocity for sound wood.
- Fig. 8
Ratio t/R of sound wall thickness ! normalized by the radius R and plotted versus the radius in cm. Failure occurs for t/R < 0.32.
Tables
Hardwoods maple 1006, 1082, 1103, 1136, 1426 birch 967, 1023, 1026, 1077, 1150 sweet chestnut 1215, 1375 oak 1382, 1416, 1430, 1450, 1495, 1500,1610 ash 1162, 1210, 1210, 1214, 1218, 1227, 1379 lime 940, 1008, 1061, 1073, 1183 plane 950, 1033 poplar 967, 1090, 1144 black locust 934, 1088, 1100, 1184, 1463 red beech 1206, 1228, 1286, 1371, 1377, 1410, 1412 horsechestnut 873, 921, 1103, 1146 black poplar 869, 943, 1034, 1042, 1048, 1057 silver poplar 821, 950, 1016, 1108 willow 912, 1028, 1155, 1216, 1333 Softwoods douglas fir 950, 1013, 1030, 1091,1209, 1295, 1323 spruce 931, 972, 1040, 1048, 1056, 1085 pine 1066, 1073, 1122, 1132, 1146 larch 1023, 1159, 1238, 1338 fir 910, 938, 996, 1100, 1166
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