VARIATION IN PULP WOOD TRAITS BETWEEN EUCALYPT CLONES ACROSS SITES AND IMPLICATIONS FOR DEPLOYMENT STRATEGIES

A total of 20 hybrid eucalypt clones at age 5½ years across four sites in coastal south-west China were assessed for volume and a subset of these for wood basic density and wood mass production. Six of these clones were also assessed for kraft pulp yield. Across the four sites the average tree volume, wood basic density, tree wood mass and pulp yield were 0.119 m3 tree-1, 474 kg m-3, 0.063 tonne tree-1 and 49.0% respectively. There were significant differences between both sites and clones for all the key traits studied. The best site for wood mass productivity had average plot wood mass of 0.239 tonne while the poorest site, only 0.128 tonne. Significant clone × site interactions were found for survival, volume tree-1, plot volume and plot wood mass. Clone and/or clone × site effects accounted for the major portion of variation for almost all the traits. However, site effects accounted for more variation on plot wood mass, indicating the importance of site selection. On account of the clone × site interactions, adopting a site-specific selection and deployment strategy was estimated to provide 15% greater wood mass yield across the region compared with a generalised selection and deployment strategy. Sebanyak 20 hibrid Eucalyptus berusia 5½ tahun di empat tapak di pantai barat daya China dinilai untuk isi padu. Sebahagian daripadanya turut dinilai untuk ketumpatan kayu dan penghasilan jisim kayu. Enam daripada klon ini dinilai juga untuk hasil pulpa kraft. Di tapak yang dikaji, purata isi padu pokok, ketumpatan asas kayu, jisim kayu pokok serta hasil pulpa ialah masing-masing 0.119 m3 pokok-1, 474 kg m-3, 0.063 tan metrik pokok-1 dan 49.0%. Terdapat perbezaan signifikan antara tapak dan klon untuk semua ciri penting yang dikaji. Tapak yang paling baik untuk penghasilan jisim kayu mempunyai jisim kayu plot sebanyak 0.239 tan metrik berbanding tapak yang paling buruk prestasinya iaitu 0.128 tan metrik sahaja. Hubungan klon × tapak yang signifikan didapati untuk kemandirian, isi padu pokok-1, isi padu plot dan jisim kayu plot. Klon dan/atau klon × tapak merangkumi sebahagian besar daripada variasi untuk hampir semua ciri. Bagaimanapun kesan tapak menyebabkan lebih banyak variasi bagi jisim kayu plot. Ini menunjukkan betapa pentingnya pemilihan tapak untuk menambah hasil ladang. Dari segi interaksi klon × tapak, amalan pemilihan serta strategi aplikasi yang berdasarkan tapak dianggarkan dapat memberi peningkatan hasil jisim kayu sebanyak 15% di daerah ini ber