文冠果育苗技术

文冠果属无患子科文冠果属木本油料植物,耐干旱、耐瘠薄、耐寒冷、适应性强,既是我国特有的优良经济林树种,也是园林庭院绿化的良好树种。目前,已被国家列为我国北方生物质能源树种,是制造生物柴油的主要树种之一,具有良好的发展前景。     

班克松引种总结

班克松原产北美洲北部 ,是美洲松中分布最广的树种 ,由于它耐寒冷、耐干旱、耐瘠薄、适应性强 ,木材又是良好的纸浆原料 ,世界上中、高纬度国家和地区都有引种。我国吉林、长春、辽宁、北京等地区也有引种 ,为了丰富胶东地区的树种资源 ,选择适生有价值的造林树种。在山东省林木种苗站的帮助下 ,于 1989年开始班克松引种试验研究工作 ,经过在垛山林场 11年的栽植试验 ,年平均高生长量 0 .31ｍ、胸径0 .5ｃｍ ,8年生前的生长量优于黑松 ,试验林的植株都已正常开花结实 ,并表现出抗旱、耐高温和耐瘠薄等特性 ,在海拔较高 ,立地比较瘠薄的山地…     

臭檀育苗试验

<正> 臭檀〔Euodia daniellii(Benn.)Hemsl.〕是芸香科吴茱萸属的落叶乔木,在我省迁西、易县、完县、内邱、武安等地均有天然散生和零星分布。臭檀不仅是优良的用材树种和庭院绿化树种,而且也是优良经济树种,其种子可榨油、含油量高达39.7％,用于油漆工业与桐油近似,它具有材质坚硬、纹理美、树形美观和耐寒、耐干旱瘠薄等特点。发展臭檀对扩大我省观赏树     

刚炬松及其对松树线虫的抗性

1.刚炬松的由来刚炬松(Pinus rigitaeda)是刚松和火炬松的杂交种。在地理上这两树种天然分布相距很远,不可能进行天然杂交。刚松分布于北美东部(从中部地区至纽约),耐干旱瘠薄,在南卡罗来纳州贫瘠的沙地上生长也很好。刚松还有很强的耐寒、抗虫性,因而     

北方主要乔木树种

红松一常绿大乔木.耐寒、耐阴、不耐水湿、干旱和盐碱.幼龄期生长较慢,中壮龄期生长快.人工母树林十年开始结实.寿命长、材质优良,为我国重要用材树种.樟子松一常绿乔木.强阳性树.耐寒、耐干旱、耐瘠薄,在轻盐碱土上可以生长成林.是我国北方荒山造林的重要树种之一.落叶松-落叶乔木.喜光、贪肥、喜湿,但不耐水淹.耐旱、耐轻盐碱.生长速度快,在一般立地条件下和在常见造林密度下,人工林第一次间伐收益时间约在林龄10～15年;在中龄林阶段,林分材积平均生长量,可以达到或者超过10m~3/年公顷.栽培容易,是北方珍贵用材树种之一.杜松-常绿小乔木.阳性、耐旱、耐寒.为北方庭院绿化、美化的重要树种.水曲柳-落叶乔木.耐寒喜水湿,稍耐阴,对光照适应幅度大,耐轻盐碱.伐根萌生能力强.萌生树前30年生长很快.木材材质优良,是北方重要用材林树种之一.胡桃揪落叶乔木.耐寒、喜水湿、在地下水位高的轻盐碱地上也能正常生长.幼年耐阴     

老龄山杨优良单株的组织培养

山杨(Populus davidiana Dode)是我国林区分布最广、面积最大、材质优良、生长迅速、耐寒、耐瘠薄并宜于山地生长的森林更新先锋树种。木材白色轻软,是造纸和火柴杆的优良原料。山杨根分     

奈曼旗南部山区樟子松造林技术

樟子松又名海拉尔松、蒙古赤松、西伯利亚松、黑河赤松,为松科大乔木,是我国＂三北＂地区主要优良造林树种之一。樟子松树高15~20米,最高可达30米,最大胸径1米左右。樟子松为生长较快的阳性树种,树冠稀疏,针叶多集中在树冠表面;寿命一般为150~200年,有的多达250年。樟子松耐干旱、瘠薄,既是干旱、瘠薄地区造林的先锋树种,也是培育防护用材兼用林和园林绿化的重要树种。     

白榆育苗技术

孟县白榆是我国白榆优良类型之一。它生长快,树干高大通直,枝条开张角度小,群众都称“钻天杨”。一般10年左右成材,胸径可达20～25公分,树高16～20米,枝下高10米左右。它材质坚韧,弹性强,不易劈裂,是建筑、车船、农具、家具的优良用材。白榆根系发达,易栽培,适应性强,有耐寒冷、耐干旱、耐瘠薄、耐盐碱(含盐量0.3～0.4%能正常生长)等特点,是营造农田防护林和四旁绿化林的理想树种,在我国北方享有一定声誉。     

樟子松

樟子松(Pinus sylvestris L.vat.mongolicaLitv.)材质优良,耐寒、耐旱、耐贫瘠,是我国北方的重要造林树种之一。内蒙古自治区是该树种自然分布最多的区域。樟子松与欧洲赤松(P.sylvestris L.)和长白松[P.syivestriformis(Takenouchi)T.Wang et Cheng]在亲缘和形态特征上具有密切的渊源关系,因此在学术研究上也占有重要位置。     

黄土丘陵沟壑区樟子松造林技术

樟子松属欧洲赤松的变种，又名海拉尔松、蒙古赤松等。在我国天然分布于东经118°21′～130°28′，北纬46°36′～53°29′的大兴安岭山地和呼伦贝尔沙地。因其耐寒、耐旱、耐瘠薄、抗盐碱、生长快、树形美、材质好、抗风沙等优良特性及其生态适应性而受到干旱地区的广泛重视。20世纪60—70年代在很多地区引种栽培，取得了较好效果，成为我国“三北”地区防护林建设的优良树种及北方干旱风沙地区的重要固沙造林树种和城市绿化树种。     

Armillaria ostoyae in managed coniferous forests in Kastamonu in Turkey

Although several Armillaria species have been reported in Turkey, there is little information about their ecology in Turkish forests. In this study, we investigated five forest stands, approximately 5–74 ha in size, in Kastamonu province in the Black Sea Region of Turkey for the presence of Armillaria species in stumps and logs. The stands were mixed Abies nordmanniana ssp. bornmülleriana and Pinus sylvestris forests managed using a selective cuttings system; the proportion of fir in the total number of stems and stumps ranged from 36 to 98%. Based on sequence analysis of the internal transcribed spacer and intergenic spacer regions of the rDNA, all rhizomorphs sampled from the stumps and logs were of Armillaria ostoyae. The size of the genets was estimated with random amplified microsatellites analysis of the isolates and ranged from single stumps to approximately 450 m². One to seven genets were found in each stand. These results indicate that the genets had arisen from spores and vegetative spread was limited on most sites.     

上海中央公园特大银杏树白蚁防治探讨

通过对上海松江中央公园内65株特大银杏树白蚁为害情况的调查,发现该公园银杏受害率为100%,其中存在活白蚁的银杏占总量的56.9%,采用毒土处理、粉剂疗法、建立白蚁监测点等措施,经过两次灭杀,活白蚁的灭杀率达到92.3%和93.3%,从而使存在活白蚁银杏树的比例从56.9%下降到2.7%,白蚁发生情况明显降低。       

我国食品中农药残留研究进展

随着人们安全健康意识提高,食品中农药残留问题更加受到重视,本文综述了样品预处理研究进展及农药残留快速检测技术研究进展,并简单分析介绍各种方法的优缺点。     

建平半干旱地区石质山地造林技术研究

研究了不同植物在石质山地的造林成活率、土壤化学性质随造林年限的变化和造林措施对土壤化学性质和植物胸径、树高年净生长量的影响。结果表明：不同植物在石质山地的成活率在21%～85%之间,其中白榆和沙打旺的成活率分别为81%和85%,而小叶杨、刺槐、栾树的成活率均在70%左右;植被能明显提高石质山地不同土层的有机质、全N、P2O5含量,但提高程度随土层深度、养分种类和造林年限的不同而不同;在同一土层,生物复合肥料、菌剂和保水剂均显著提高土壤有机质含量（p〈0.01）并显著降低土壤P2O5含量（p〈0.01）;只有保水剂可引起土壤全K含量的明显升高;生物复合肥料、菌剂和保水剂均显著提高白榆、小叶杨、刺槐、栾树树高和胸径的年净生长量,但保水剂的提高程度最高。     

植物DNA甲基化研究进展

植物经常暴露在各种生物和非生物的胁迫之下,这些胁迫会影响植物的生长发育和繁殖并最终导致植物死亡。为了抵御不利的环境条件,植物已经进化出复杂而精细的网络来感知胁迫并激活防御系统。为此,植物激活许多信号转导通路,这些信号转导通路可以改变一些胁迫响应基因的表达,从而引起植物形态、生理和生化的改变以适应逆境。DNA胞嘧啶甲基化是高等真核生物的主要表观遗传机制之一,在维持基因组稳定性和调节基因表达方面起着关键作用。表观遗传变异比遗传变异更为灵活。一旦环境条件发生变化,为了适应新的环境植物都会发生表观遗传的改变。许多研究表明DNA甲基化参与植物的发育和应激反应。基于相关研究对DNA甲基化进行了综述,对植物逆境胁迫有重要意义。     

木材碳封存研究进展

碳封存可以分工业封存和生物封存, 工业封存包括地质封存、海洋封存、矿石碳化以及工业循环利用, 这些方法能快速回收CO₂, 但工艺流程技术复杂, 成本较高。木材碳封存是生物碳封存的一种类型, 树木光合作用吸收的碳主要存贮在木材中。运用木材密度、微密度等检测仪器, 通过确定木材密度变化, 结合其含碳率来计量木材的碳封存过程以及封存过程中碳的分配格局, 同时研究其与环境因子的相关性, 可以为研究森林的碳吸收动态提供便捷的方法和科学的依据。     

Tree regeneration in patch cutting in Norway spruce stands in northern Finland

The study focused on the success of regeneration on patch cuts in spruce-dominated stands in terms of stocking and tree height. It was based on an experiment in the Kainuu region in northern Finland. The experimental design included 8 stands with 58 clearcut patches of variable size (0.09–0.37?ha), on which either natural regeneration without site preparation or site preparation and planting of Scots pine was applied. A regeneration survey was conducted 13–15 growing seasons after treatments. Patches without site preparation had been restocked quite well from natural seed sources. The average number of trees was about 11,000?ha^?1, of which 1700?ha^?1 crop trees. With site preparation and planting, the stocking levels were also very high, 25,000 and 2100?ha^?1, respectively. One hundred percent of the planted patches and 75% of the naturally regenerated patches had an acceptable density. Restocking was equally good across the range of patch sizes. Tree growth had been somewhat slower in the smallest patches than in the largest ones in the range. Natural regeneration was capable of yielding good regeneration results in most patches, especially when site preparation was applied. Stocking levels and height development were higher yet in the planted patches.     

Changes in micropores in dry wood with elapsed time in the environment

To investigate the changes in microstructures of wood with elapsed time in the environment, CO₂ adsorption onto dry wood was measured at ice-water temperature (273 K) for samples aged from 0.1 years to over 1000 years. The micropore size distribution was obtained using the Horvath-Kawazoe method. Micropores smaller than 0.6 nm in wood decreased in number with elapsed time in the environment, and a negative correlation was found between cumulative pore volume for pores smaller than 0.6 nm and elapsed time in the environment. Cumulative pore volume in the 1000-year sample was almost half of that in the 0.1- year sample. Micropores smaller than 0.6 nm in wood with a few decades or more of elapsed time increased in number after rewetting and drying. Consequently, microstructures of wood with longer time elapsed in the environment were considered to be more stable, because of longer-term thermal motion and possibly more repeated moisture adsorption and desorption and/or temperature variation in the environment.     

Natural regeneration in patch clear-cutting in Picea abies stands in Southern Finland

Abstract

The success of natural regeneration on patch clear-cuts in Norway spruce stands in Southern Finland was examined in terms of stocking and tree height. The experiment was established in mature spruce stands in the submesic Myrtillus (MT) site type. In each of the eight study sites, three plots were treated with clear-cutting and planting, clear-cutting with partial tree retention and planting, and patch clear-cutting without site preparation, respectively. In three of the study sites, one plot with patch clear-cutting and site preparation was established. Each plot was 1 ha, out of which three patches of 40×40 m were clear-cut in the patch treatments. 10–11 years after cutting, the patches had on average 1316 crop trees ha^–1, of which 91% were spruces. Some 27% of the stands were up to the target stocking level (≥1600 ha^?1), and 36% were at least satisfactory (≥1300 ha^?1). Site preparation did not yield greater stocking levels on patches, but that result is ambiguous due to a difference in initial stocking. The average spruce tree height in the patches (0.76 m) was much smaller than in the case of clear-cutting and planting (2.42 m). In conclusion, the patches had been restocked tolerably well with spruce and birch for practical purposes during the 10- to 11-year period, but the regeneration process had been very slow compared to clear-cutting and planting.