红豆树等6种珍贵用材树种的生长特性和材性分析

Studies on Growth and Wood Property of Six Precious Timber Species

利用浙江龙泉和庆元两地在较好立地上营造的21 36年生红豆树、江南油杉、伯乐树、闽楠、刨花楠和乐东拟单性木兰6种珍贵用材树种的片林,以研究其生长、干形和木材基本密度的变化规律。研究结果表明,红豆树是一个树高和胸径生长量大、径生长速生持续期长、木材基本密度中等及其径向均匀性较高的珍贵用材树种,平均年轮宽度达到0.8 1.2 cm,36年生时按宽度和面积计算心材比例分别为60.57%和37.47%。因红豆树分叉干特性明显,在栽植的第2年就应及时修枝抹芽和施肥,以培育树干通直、心材比例高的优质干材。江南油杉和闽楠等其它5种珍贵用材树种皆较少分叉干,其树干通直。闽楠以材质优良而闻名,木材密度中等,虽然其生长速度较慢,但生长势很强,年生长量稳定,加之树冠窄小,适宜长周期大径材的培育;伯乐树生长速度中等,木材密度略低,但其径向均匀性较高,宜作为优质的工艺材来培育;树冠窄小的乐东拟单性木兰生长速度中等,但其木材密度大、径向均匀性高,是优良的珍贵用材树种;江南油杉是个早期生长快而后期生长慢,木材密度中等的针叶树种,可通过加强经营管理延长速生期和提高木材密度的径向均匀性;刨花楠虽然生长速度中等,但其木材密度却较低,浸水有粘液,不宜作为珍贵用材树种培育。

The 21-to 36-year-old plantations of six precious timber species including Ormosia hosiei,Keteleeria cyclolepis,Bretschneidera sinensis,Phoebe bournei,Machilus pauhoi,and Paramecia lotungensis,which locate in Longquan and Qingyuan of Zhejiang province were selected to study the variation in growth,stem form and wood basic density.Of the six tested species,O.hosiei exhibits larger height and DBH increment,longer fast-growing period in diameter,medium wood basic density and smaller radial variation,and its annual ring width varies from 0.8~1.2 cm,whereas the heartwood proportion by ring width and area being 60.57% and 37.47% respectively.Considering the stem forking characteristic of O.hosiei,timely pruning and wiping away the buds,and appropriate fertilizing at two years after planting are necessary to produce high grade trunk wood with better stem straightness and higher heartwood proportion.The other five species exhibited less stem forking and more straight stem.Ph.bournei is famous for its excellent wood quality with medium wood density,strong growth potential,stable annual increment and narrower crown,indicating that it is more suitable for cultivating as long-period and big-diameter timber,although its growth rate is relatively slow.B.sinensis is more suitable for cultivating as good technological wood,as it exhibits medium growth rate,lower density but smaller radial variation;P.lotungensis is also an excellent precious timber specie with higher wood density and radial uniformity,though its growth rate is medium.K.cyclolepis is a coniferous tree,with fast growth rate in early period and slow rate in late,and its wood density is medium.It is proposed that the fast growing period could be prolonged and radial uniformity of wood density be improved through the enhanced cultivation management.M.pauhoi exhibits medium growth rate,lower density and wood mucous,indicating that it is unsuitable for cultivating as precious timber trees.