Abstract:
Anatomical structure of wood fifteen coniferous speces viz Anies pindrow, Cedrus deodara, Cupressus arizonica, C. fenebris, C. sempervirens, SC. Toruosa, picea smithiana, Pinus geradiana, P. halepensis, P. roxburghii, P. wallichiana, Thuja orientallis, Taxus baccata, Juniperus polycarpos and Araucaria cookii was studied. Anatomical characteristics and general features of wood of these species were described. Total thickness of cell wall and thickness of individual cell wall layers of first twelve conifers mentioned above were also estimated.
Cell wall polysaccharide is namely holocellulose, alpha cellulose, hemicellulose, lignin and pectin were estimated from wood of trunks as well as branches of conifers and some fast-growing angiosperms (Eucalyptus and Populus species). Wood from trunks and branches of 13 conifers were analysed for holocellulose, aplhacellulose and lignin contents. hemicellulose and pectic contents of wood from trunks of 13 and branches of 10 conifers were estimated. Woods from trunks of 15 and branches of 11 fast growing angiosperms were analysed rom holocellulose, aplhacellulose and lignin content.
In coniferous wood obtained from trunks the amount of holocellulose, alpha cellulose, hemicellulose, lignin and pectic ranged from between 61.87-75.06% (Cupressus semepervirens-C. torulosa), 31.53 – 49.33% (C. ARIZONICA-Pinus roxburghii), 5.85-26.42% (C. torulosa-Taxus baccata), 23.52-41.33% (Pinus wallichiana-Cedrus deodara) and 1.73-4.39 (P. roxburghii-Cupressus arizonica) respectively. On the other hand, values for these components in branch wood ranged between 60.07-77.23% (Cupressus torulosa-Pinus geradiana), 10.67-23.22% (Thuja orientalis- C. arizonica), 31.40-40.93% (Juniperus polycarpos-P. roxburghii) and 1.53-7.19% (Cedrus deodara- Cupressus arizonica) respectively.
In angiosperms holocellulose, aplhacellulose and lignin contents of trunk wood ranged between 67. 80- 78.52% (Eucalyptus microtheca- populus nigra), 37.68-48.15% (E. globulus- P. nigra) and 22.01-32.28% (E. maculate- E. microtheca) respectively. whereas in branch wood number of theses polysaccharides varied between 67.22 -78.63% (E. tereticornis- P. deltoides), 36.25-50.53% (E. citriodora- P. ciliata) and 20.96-32.77% (P. deltoides – E. tereticornis) respectively.
Results showed that hardwoods on the average contained more holocellulose and alpha cellulose than softwoods and reverse was true for lignin content. However, amount of these polysaccharides in trunk wood and branch wood did not show much variation in the same species.
