Table 1.
Characteristics of the three grades of compression woods (CW) and opposite wood (OW)
| Characters | ||||
|---|---|---|---|---|
| Wood types | Lignification of compound middle lamella at cell corners | Lignification of S2L at cell corners | Lignification of S2L around cells | Intercellular spaces |
| Opposite wood (OW) | +++ | - | - | - |
| Mild compression wood 1 (MCW1) | ++ | + | - | - |
| Mild compression wood 2 (MCW2) | + | ++ | ++ | ++ |
| Severe compression wood (SCW) | - | +++ | +++ | +++ |
-, no lignin autofluorescence/intercellular spaces absent; +, weak lignin autofluorescence; ++, moderate lignin autofluorescence/moderately frequent intercellular spaces; +++, strong lignin autofluorescence/numerous intercellular spaces