Development and validation of a stem volume equation for Cupressus lusitanica in Gergeda Forest,Ethiopia

Stem volume equations were fitted for Cupressus lusitanica in Gergeda Forest, Ethiopia using six different established equation forms. A total of 260 trees were measured for their diameter at breast height (D), total height (H?)and stem volume using destructive sampling methods. The data set was randomly divided into equal size for equation development and equation validation. Five fit statistics comprising of the fit index, root mean square error, bias (ē?), absolute mean deviation and coefficient of variation were used to evaluate the performance of each equation. Among the different equations, the Schumacher and Hall function of the form V = b₁D^b2H^b3 (model 5), which estimates volume (V?) using diameter at breast height and total height as predicting variables, performed best and was then fitted to the combined data set for prediction of volume over-bark of C. lusitanica in Gergeda Forest. Overall, volume equations with two independent variables (D and H?) performed better than those with only one variable (D). The equations developed in this study can provide forest managers with accurate estimations of stem volumes for C. lusitanica in Gergeda Forest.     

柏类引种试验研究

对柏类４个树种墨西哥柏,绿干柏,垂柏,巨柏共１２个种源的引种表明,不同树种和种源树高,胸径增最大年份分别出现在造林后第４年和第５年;造林后１０ａ,lay status     

巨柏群落特征的研究

巨柏是西藏特有的珍稀濒危植物,天然群落稀少.选择巨柏群落分布较集中的地段设置样地,并以植物群落调查样地资料为基础,分析了群落的种类组成、区系特征、群落外貌、垂直结构和水平结构等群落学特性.对不同地段的7块样地材料分析结果表明:调查样地共有维管植物90种,分别隶属于41科77属,其中只含一种的属占84.42%.巨柏群落区系组成、群落植物生活型、叶的性质等特征,总体都反映了群落的温带性质.群落垂直结构明显,可分为乔木层、灌木层、草本层,也有部分层间植物,乔木层郁闭度为0.3～0.5,巨柏为乔木层的单一优势种,而群落植物的水平分布不均匀.与林芝云杉林比较,巨柏群落物种多样性偏低.     

巨柏种群的生态地理分布与群落学特征

对巨柏的地理分布和群落学特征进行研究.结果表明:巨柏的生态地理范围狭小,主要在雅鲁藏布江两岸呈狭带状和斑块状间断分布;目前巨柏已被分割成4个种群,种群间环境异质,水平地带上跨越了湿润、半湿润和半干旱3大生态区.巨柏群落中共调查到维管束植物43科106属130种,巨柏群落的植物区系古老,属的组成较为复杂,区系中特有成分突出,含有大量的中国(西藏)特有种和中国-喜马拉雅分布种.从属的地理分布类型来看,巨柏群落具有明显的温带性质,属于北温带分布类型.巨柏是乔木层的单优势种,灌木层和草本层以全缘草质小型单叶地面芽植物为主.群落植物组成从半湿润区到半干旱区过渡中逐渐稀疏,结构也趋于简单.     

珍贵用材树种柏木轻基质容器育苗试验研究

This paper dealt with an experiment on container seedlings culture with nonwoven and light medium for Cupressus funebris, a precious timber tree species, through orthogonal design. The effects of container height, quantities of controlled release fertilizer and the medium proportion on seedling quality of Cupressus funebri were studied. The results showed that seedling height, ground diamater, divarication number and the ratio of seedling height to ground diameter of Cupressus funebri were significantly affected by the height of container and the quantities of controlled release fertilizer, and little influenced by the medium proportion. There were significant different influences on seedling growth among different treatment combinations. The treatment combination No.9 was the best one with averaged seedling height, ground diamater, divarication number and the ratio of seedling height to ground diameter of 21.75 cm, 0.271 cm, 10.7 branches and 80.29, respectively. The treatment combination of No.6, No.3 and No. 5 were relatively good treatment. The length of seedling container of nonwoven with diameter of 5 cm for Cupressus funebris, could be selected as 10—12 cm. The quantities of controlled release fertilizer of 3 kg·m^-3 and the seedlings density of 215—220 plants·m^-2 could be the optimal for nursing seedling with high quality. The costs of medium proportion on several container seedlings base of Zhejiang Province were compared and analyzed.     

岷江柏种群结构及其特征研究

对川西北的理县、马尔康、金川、小金、丹巴5个县的岷江柏种群结构及特征进行研究,结果表明:该种群的36个样方中,幼苗所占的百分数均超过57%,岷江柏种群密度呈增长趋势,种群结构稳定,正向良性发展.对5个县的岷江柏种群数量特征进行比较发现,岷江柏天然林群落基本上为单优势种群群落.为此,提出了对岷江柏种群的几点保护建议.     

银荆、墨西哥柏施肥试验初报

在昆明立地条件较差的宜林荒山上造林，定植塘内施基肥，间接地改善了土壤肥力条件，促进了树木生长。施肥与不施肥相比。银荆树平均每年高生长增加１０２．２ｃｍ，径生长增加０．６ｃｍ；墨西哥柏平均每年高生长增加２９．３ｃｍ，径生长增加０．３２ｃｍ，定植塘内施基肥的增效以施复合肥最好。最佳施用量每塘１００ｇ，２５０．５ｋｇ／ｈｍ２。肥效排列顺序为：进口复合肥＞处理垃圾肥＞羊厩肥＞桐油枯。     

白水江干旱河谷区荒山造林试验研究

白水江干旱河谷区是长江上游生态环境最脆弱区域之一,该区域植被恢复尤为因难。在干旱河谷核心区域不同立地条件下通过多年造林试验,岷江柏、侧柏造林成效较好,刺槐造林成效相对较差。     

藏柏36个家系自由授粉子代测定与优选

对云南省内的藏柏8个种源36个家系开展自由授粉子代测定,结果表明,地径、树高和冠幅在种源和家系水平上均存在一定的变异,3个性状在种源和家系间都存在显著或极显著差异;地径、树高和冠幅种源遗传力分别为0.82、0.62和0.84,家系遗传力分别为0.76、0.76和0.77,地径、树高和冠幅在种源和家系水平上受强度遗传控制。选择出2个优良种源,地径、树高、冠幅平均遗传增益分别为11.36%、5.78%和10.1%;选择出4个优良家系,地径、树高和冠幅平均遗传增益分别为16.23%、16.22%和17.46%。     

柏木生长性状变异研究（英文）

[目的]探索重庆市柏木生长性状变异情况,以期为后期开展良种选育及改良奠定基础。[方法]对重庆市綦江、彭水和酉阳3个优良柏木林分的生长性状等进行调查。[结果]彭水林分生长表现最好,綦江林分次之,酉阳林分最差,材积生长平均值分别为0.14、0.11和0.06 m3。林分间,主要生长指标的变异系数均在11.31%以上,材积变异系数最大为39.11%,林分内,树高的变异基本相当,均在20%左右。胸径的变异以綦江最大,为42.42%,酉阳次之。材积的变异与胸径一致,结实系数以彭水林分变异最大,利用该林分建立母树林或对其所选优树建立种子园比较有利。[结论]开展柏木种源选择很有必要。