雷州桉树人工林下土壤磷肥活化效果及机理研究

应用不同活化剂处理不同性质的磷肥，对其在玄武岩母质的桉树人工林土壤中的生物效应及其作用机理进行了研究。结果显示：（1）在玄武岩桉树人工林土壤上，施活化剂处理磷肥均能显著地提高桉树生长量，其中经有机2号活化剂处理后的磷矿粉增加生长量最大，有机活化剂的最适使用农度为5％，（2）玄武岩桉树人工林土壤中的Fe,Mn,与P素有效性关系密切，且在还原条件下的土壤Mn对磷的固定作用更大，Si有利于土壤中P的释放；适量的Ca也有利提高P的活性；（3）供试活化剂不仅可促进难溶P的释放，还可控释水溶性P，使土壤供磷性能平衡；（4）在玄武岩砖红壤－桉树体系中，活化剂对P的促释和控释机理在于通过对土壤Fe,Mn,Al含量的调节而实现对P的活化。     

科学经营桉树人工林 促进广东林业可持续发展

根据广东林业产业的现状,从实现林业可持续发展的角度上论述了林业实施分类经营改革,实行分类指导是实现新世纪广东林业持续稳定健康发展的必要措施;阐明科学经营、适度发展桉树人工林符合我省林业产业建设及经济发展的需要。重申生态与经济并重是建设现代林业的必由之路。     

我国桉树青枯病研究进展

桉树青枯病害是危害桉树生产的主要病害,近年来桉树青枯病的流行和发生对我国南方桉树产业造成很大经济损失.本文对当今主要桉树青枯病病害特点,青枯病的发生和流行因素,青枯假单胞杆菌对寄主桉树的致病机制及对抗病的差异和抗病机理等研究成果和现状作一概述,并就存在的问题提出相应的建议.     

Relationships of anatomical characteristics versus shrinkage and collapse properties in plantation-grown eucalypt wood from China

To explore the influence of the basic density on collapse-type shrinkage properties and to quantify the relationships of the main anatomical features with shrinkage and collapse properties, all above-mentioned parameters were determined and analyzed for three species of collapse-susceptible eucalypts, Eucalyptus urophylla, Eucalyptus grandis, and E. urophylla × E. grandis, planted in South China. The correlation coefficients were also determined and the corresponding regression equations were established with the anatomical parameters measured by using multiple linear regression. The results indicated that: (1) basic density was strongly positively linearly related to both unit tangential shrinkage (r = 0.970) and unit radial shrinkage (r = 0.959), weakly positively related to total shrinkage (r = 0.656 and 0.640 for tangential and radial, respectively), and weakly negatively related to residual collapse (r = 0.632 and 0.616 for tangential and radial, respectively). (2) The main factors affecting unit shrinkage were cell wall proportion (WP), microfibril angle (MFA), and double fiber cell wall thickness (DWT); factors playing an important role in total shrinkage were WP, ray parenchyma proportion (RP), and MFA, while RP had the highest effect on residual collapse (r = 0.949 and 0.860 for tangential and radial, respectively). (3) All corresponding regression models obtained were very suitable for the evaluation of relationships between the anatomical parameters and unit shrinkage, total shrinkage, and residual collapse, as measured using a moisture content of 28% as the fiber saturation point for all specimens.     

Intercropping eucalypts with maize in Minas Gerais,Brazil

This project was established in the Doce River Valley in the state of Minas Gerais, Brazil. The objective was to study the effect of intercropping one, two, three and four rows of maize between eucalypt seedlings planted in a 3.0×2.0 m spacing. Eucalypt data were collected at the age of six months when the maize was harvested. One row of maize intercropped between the rows of eucalypt did not lower the initial growth and survival of the trees, but did reduce the costs of the eucalypt plantations by 60%. Other treatments involving additional rows of maize reduced plantation costs, but also reduced the initial growth and survival of the trees.     

滇南高海拔地区桉树优良无性系的选择及其制浆造纸性能研究

通过对所引种培育的10个桉树无性系的测定和选择,杂交桉树(尾巨桉)在造林中表现优异,4年生时有三个品系年均蓄积增长量在30m3.hm-2以上,在对比试验林中生长较好的无性系,在大面积示范种植中也显示其生长优势,推广种植的两年生桉树年平均生长量均为33m3.hm-2以上,第一年至第二年的净生长量为48m3.hm-2以上。通过对生长表现较好的四个桉树优良无性系制浆造纸应用进行评价研究,它们的化学成分抽出物含量偏低,纤维素及综纤维素含量偏高,对纸浆得率的提高有利,纤维形态属于桉木中的中等水平,LH110和LH107的硫酸盐浆得率能达到52%-53%;硫酸盐浆的粘度都在1430ml.g-1以上,LH110的则在1500ml.g-1以上,从四个无性系漂白硫酸盐浆所表现出来的强度指标来看,可划为阔叶硫酸盐浆中的高强度纸浆;白度指标值高达94.8%-97.6%,完全可以进入超高白度纸浆的应用市场,表现出更高的附加值。     

我国桉树研究现状与发展态势

我国引种桉树将近120年,随着经济的发展,她与其它许多相关学科的发展不断成长和壮大,因而在理论、研究方法和技术上取得了长足发展。本文回顾了我国桉树研究的发展历史,从研究队伍和机构、桉树科研产出、桉树研究中存在的问题三个方面综述了桉树科研的进展及其存在的不足。最后对我国桉树研究的发展趋势作了展望,这对我国桉树科研与桉树产业的可持续发展具有十分重要的借鉴意义。     

林分密度对桉树幼龄能源林的影响

对0.5年生3种不同密度配置的幼龄尾巨桉优良无性系DH32-29各器官生物量、热值以及灰分进行了调查和测定,结果表明:所选3种密度间树高差异显著,基径差异达到极显著水平,随着密度的增加,树枝、叶片、树干的生物量分别呈现减少趋势,密度与树枝和树干生物量的相关性达到了0.01极显著水平;单株生物量随密度的增大而减小,林分生物量则相反;单株热值无显著差异,仅单株平均灰分含量高密度与中密度存在显著差异。综合分析,高密度0.25 m×2 m林分生物量最大,其灰分含量比低密度的林分低,适合作为能源林培育密度。     

Age trends and correlations of growth and wood properties in clone of Eucalyptus urophylla × E. grandis in Guangdong, China

We assessed growth traits and wood properties of DH 32-29, a clone of Eucalyptus urophylla × E. grandis, at age of two to six years in Guangdong in China. Analysis of variance of studied traits showed that there were significant differences (1% level) on all studied traits among ages except for wood basic density. Analysis of age trends of growth traits and wood properties revealed that rotation length of DH32-29 should be more than six years or longer. Phenotypic correlations among traits at individual ages indicated that correlations between growth traits were strongly positive. There was significant change in relationship between growth and wood basic density with increasing age, ranging from -0.03 to -0.54 at 2 and 5 year and 0.003 to 0.3 at 3, 4 and 6 year.Correlations between Pilodyn pin penetration and basic density measuredon increment cores showed that Pilodyn could rank or group genotypesor sites into density classes, but failure to predict individual tree and individual clone.     

尾细桉等5种桉树无性系生物量和能量的比较研究

对广东廉江石岭林场尾细桉等5种7.5年生桉树无性系的生物量和能量进行了研究。结果表明:不同无性系各组分生物量的分布规律均以干的最大、叶的最小,枝、根、皮介于中间;5种桉树无性系各组分的生物量排序为:赤桉、尾细桉、巨尾桉为干根枝皮叶,雷林1号桉为干根皮枝叶,尾叶桉为干枝根皮叶。人工林生物量现存量的排列顺序为尾细桉(161.60 t.hm-2)巨尾桉(127.96 t.hm-2)尾叶桉(112.60 t.hm-2)赤桉(83.81 t.hm-2)雷林1号桉(71.36 t.hm-2)。各组分的灰分含量各不相同,以叶最高(4.08%~6.88%),干最低(0.17%~0.43%)。不同组分的干质量热值介于17.94~21.06 kJ.g-1间,去灰分热值介于18.57~22.12 kJ.g-1间,均以叶的值最高。植株体的平均干质量热值和去灰分热值分别为19.02~19.32、19.49~19.85 kJ.g-1,平均干质量热值的排序为雷林1号桉尾叶桉尾细桉赤桉巨尾桉,平均去灰分热值的排序为雷林1号桉赤桉尾叶桉尾细桉巨尾桉。5种桉树无性系林的能量现存量为1 360.73~3 067.47G J.hm-2,大小顺序为尾细桉巨尾桉尾叶桉赤桉雷林1号桉。综合生物量和能量现存量分析,尾细桉选作能源树种最为理想,巨尾桉和尾叶桉次之,赤桉与雷林1号桉最差。