Growth and heartwood characteristics of Ormosia hosiei plantations

Key words: 
• silviculture /
• Ormosia hosiei /
• plantation /
• growth /
• wood basic density （WBD） /
• heartwood

Abstract: In order to study the effects of site conditions，planting densities，and stand ages to the growth and wood characteristics of Ormosia hosiei plantations，we used twenty-three，38-year-old plantations of O.hosiei，and analyzed the growth and heartwood characteristics with statistical methods. Trees were grown in eight different locations of two provinces （Zhejiang and Fujian） and represented different site conditions，planting densities （630-500 treehm－2），and stand ages. Choosing typical site-plot （15 m 20 m） and made each trees survey （20－50 sample trees）. The survey contained the height，diameter at breast height （DBH），stem straight，stem fullness and stem forking，after that，wood cores was picked. Results showed that O.hosiei exhibited more stem forking （59.1%） and lower stem straightness than other wood plants. O. hosiei grew faster in the early stages than other wood species. The wood basic density （WBD） of O. hosiei，which was ranging from 0.50－0.59 gm－3，was similar for each site，and having an average of 0.543 2 gm－3. WBD had an increasing tendency from pitch to outside （1－5 rings：0.497 6 gm－3，6-10 rings：0.524 6 gm－3，11－15 rings：0.544 8 gm－3，16－20 rings：0.560 5 gm－3，21－25 rings：0.566 1 gm－3，26－30 rings：0.566 7 gm－3，31－35 rings：0.571 0 gm－3，and 36－40 rings：0.552 7 gm－3），and having a relatively stable state after the 35th annual ring. But radial uniformity was higher，the average of the standard deviation was 0.031. Heartwood radius （HR） was significant，linear，and positively correlated to DBH （R2 = 0.749，F1，315 = 17.91，P = 0.005），and heartwood area （HA） was correlated significantly and positively as a power function to DBH （R2 = 0.771 9，F1，315 = 20.3，P = 0.004）. Thus，recommendations were the following: timely pruning and wiping away the buds to produce high grade trunk wood，utilizing good site conditions and suitable planting densities to promote radial growth and volume，and extending the breeding-cycle and increasing the diameter growth-rate to increase the timber diameter and promote a higher heartwood ratio of high-value wood.［Ch，2 fig. 5 tab. 24 ref］