马尾松与枫香混交林造林技术分析

指出了百色地区有较广泛的马尾松林地,但由于长期以马尾松为树种,土壤肥力下降,马尾松产量也下降。因此以枫香与马尾松营造混交林,用以提高土壤有机质含量,增加生物多样性,提高马尾松的产量,促进马尾松优质生长。精选造林材料,探讨了马尾松与枫香混交林的造林技术,重视病虫害防治,结果证明:选择枫香与马尾松混交造林,并采用块状造林技术,具有良好优势。     

马尾松混交林土壤持水性和肥力特征

通过马尾松与格氏栲、青栲、火力楠及杉木等树种混交试验,13年生时测定不同混交林土壤的持水性、土壤结构和养分。结果表明,马尾松格氏栲和马尾松青栲混交林土壤饱和持水量大于马尾松火力楠和马尾松杉木混交林,土壤结构破坏率以马尾松格氏栲和马尾松青栲混交林较低,而马尾松格氏栲混交林土壤孔隙度最大,且马尾松格氏栲和马尾松青栲混交林土壤有机质、全量养分和速效性养分含量高于其他2种混交组合。格氏栲和青栲为马尾松伴生树种可以促进林分涵养水源,提高土壤肥力。     

马尾松毛红椿混交林生长效果和土壤肥力研究

通过马尾松毛红椿混交林和马尾松纯林生长量和土壤肥力状况的对比研究,结果表明,马尾松毛红椿混交林中马尾松胸径、树高、单株材积和总蓄积量均高于马尾松纯林。混交林中马尾松和毛红椿的生长量呈现出马尾松毛红椿混交比例4∶1>3∶1>2∶1的规律。马尾松毛红椿混交林土壤水分物理性质和化学性质均优于马尾松纯林,营造马尾松毛红椿混交林有利于提高土壤肥力。由于毛红椿生长快于马尾松,营造混交林以带状混交为佳,且毛红椿比例宜小。     

闽南山地马尾松-闽粤栲混交林与马尾松纯林生物量比较研究

对马尾松-闽粤栲混交林与马尾松纯林的生物量进行了测定,并将两种林分的乔木层、灌木层、草本层和凋落物层的生物量进行了对比,结果表明:马尾松-闽粤栲混交林与同龄的马尾松纯林相比,无论乔木层、灌木层、草本层还是凋落物层的生物量均大于马尾松纯林,马尾松-闽粤栲混交林总生物量大于马尾松纯林。说明马尾松与闽粤栲混交提高了林分生长量,促进了马尾松生长,提高了林分生物多样性和改善了土壤肥力。马尾松与闽粤栲混交是马尾松经营中一种较合适的模式。     

马尾松幼林抚育经营方法与管理技术

指出了马尾松具有生长迅速、环境适应性强的特点,在我国南方地区绿化中得到广泛的种植和培育。为了提高马尾松培育和栽植效果,十分有必要针对马尾松幼林抚育工作进行研究,并在明确其经营方法的基础上对管理技术进行优化,力求能够促进马尾松种植和培育工作高效推进。简要分析了马尾松物种的特性,对马尾松幼林抚育经营方法和管理技术进行了论证,并提出了相应的建议,希望可以促进马尾松种植工作取得更大的经济生态效益。     

浙江省马尾松速生丰产用材林经济效益分析与评估

根据浙江省马尾松有关资料，针对本省经济状况，对马尾松速生丰产用材林的不同生产阶段作了分析，再以速生丰产用材林的基准年龄进行统一核算，最后作出马尾松速生丰产用材林经济效益的评估，为合理开发利用马尾松分布区生态资源、正确选择商品材基地提供理论依据，从而提高马尾松造林的生态、经济效益。     

菌根化马尾松植株抗旱性研究

通过对干旱胁迫下菌根化马尾松松针中细胞膜透性及保护酶的活性变化进行研究,分析了细胞膜保护酶在外生菌根提高马尾松抗旱能力过程中的作用,结果表明,接种劣味乳菇的菌根化马尾松植株的抗旱能力较强,其次是接种紫金蜡蘑的菌根化马尾松植株,CK马尾松植株抗旱能力较差;劣味乳菇菌根化马尾松植株MDA含量和SOD活性的提高幅度均较小,而POD活性和细胞膜透性变化幅度较高,且与马尾松植株的抗旱能力呈正相关。表明细胞膜保护酶的调节作用在外生菌根提高马尾松植株抗旱能力过程中发挥了一定作用。     

沅陵县马尾松造林前景分析

文章阐述了马尾松作为工业原料林和优质建材资源的重要性,分析了马尾松造林的经济效益,指出了造林经营户在造林树种选择上忽略马尾松的原因,并简述了马尾松造林技术。以期达到沅陵县在造林树种选择上,将马尾松作为一个主要树种,促进沅陵县马尾松资源的正常更新和发展。     

马尾松多树种混交林水文效应和土壤性质研究

采用马尾松、木荷、台湾相思按2∶7∶1和4∶5∶1两种比例混交及马尾松、火力楠、杉木按1∶5∶4和5∶4∶1两种比例造林,19年生时研究其水文特征和土壤肥力状况。结果表明:马尾松、木荷、相思混交林持水能力高于马尾松、火力楠、杉木混交林,其中按2∶7∶1配比的马尾松、木荷、相思混交林其持水量最大,比按1∶5∶4配比的马尾松、火力楠、杉木混交林大19.43%,比按5∶4∶1配比的马尾松、火力楠、杉木混交林大24.43%;马尾松、木荷、相思混交林土壤肥力状况优于马尾松、火力楠、杉木混交林;马尾松、木荷、相思混交林具有更强的持水固土改土能力。     

4种珍贵阔叶树与马尾松混交试验初报

采用4种珍贵阔叶树与马尾松进行混交造林试验,结果表明:4种针阔混交林中,不同珍贵阔叶树的平均胸径、平均树高、高径比及林分蓄积量存在极显著差异,林分生长表现为枫香香樟闽楠红楠。不同珍贵阔叶树对马尾松生长有不同影响,马尾松林分蓄积量存在极显著差异,马尾松×闽楠混交林中的马尾松林分蓄积量最大,其余依次为马尾松×红楠、马尾松×香樟、马尾松×枫香。不同混交模式的林分总蓄积量从高到低依次为马尾松×闽楠马尾松×枫香马尾松×红楠马尾松×香樟,但其差异不显著。     

白榆无性系数量性状遗传相关分析

对24个白榆无性系的6个性状进行遗传相关分析表明，主干高、胸径、全高、冠幅与主干材积呈极显著正相关；竞争枝数与主干材积呈极显著负相关。通径分析表明主干高、胸径对主干材积直接作用最大，选择时是首要因素。竞争枝数对主干材积直接作用和剩余效应均为负，减少竞争枝数对增大主干材积有利。冠幅对主干材积直接作用为负，与主干高、胸径呈负相关。选择丰产窄冠白榆无性系是可能的。     

杉木不同种源优系间杂交遗传分析

对 10年生杉木不同种源优系 5× 5双因素交叉式遗传设计试验林的胸径和木材比重两性状进行了测定和遗传分析。结果表明 ,两性状在组合间均达极显著差异 ,组合内亲本的一般配合力和杂交的特殊配合力亦达显著差异水平。胸径的一般配合力方差分量为 70 32 % ,而木材比重的一般配合力方差分量则为 5 3 84 % ,胸径、木材比重广义遗传力分别为 4 2 4 9%和6 9 6 0 % ,狭义遗传力分别为 2 9 88%和 37 0 0 %。亲本川 15、闽 4、湘 6、粤 11对胸径生长有较高一般配合力正向效应值 ,同时亲本闽 4对木材比重亦有较高的一般配合力正向效应值。另有 4个杂交组合浙 13×浙 8、湘 30×川 18、闽 16×湘 6、川15×闽 4对胸径生长有较高的特殊配合力正向效应值 ,对胸径和木材比重均表现出正向效应的只有闽 16×川 18和粤 5×湘 6组合     

油桐育种程序系列研究

经对来自１０个省（区）１８４个种质资源号及２７５个地方品种、单亲家系、双亲家系和无性系系统的研究分析与选育，基本摸清油桐主要性状的遗传参数，并得出油桐为“常异花授粉树种”的结论；制定了油桐育种程序和途径，选育出３个优良家系、４个优良无性系、１个“矮早丰”优良品种和１个优良杂交组合；收集了来自全国油桐产区的种质资源４５１个；生产并推广良种１３ｘ１０４ｋｇ。应用这些良种的遗传增益（△Ｇ）在３４．０％－５９．８％。这一研究为油桐生产和遗传改良提供了理论依据，并提供了部分育种和生产资料。     

毛竹种源多性状综合选择的研究

应用主成份回归分析对16个毛竹种源的鲜笋产量、质量、新竹胸径、单株竹重、总竹重和抗性等性状进行定量的综合评价.筛选出综合性状优良的Ⅰ类种源4个,即福建武夷、福建建瓯、福建沙县和江西上饶种源.中选种源的鲜笋重大于群体平均值17.21%～16.42%,8种人体必需氨基酸含量平均增益15.01%,感病虫指数低于平均值24.93%～63.37%.     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.