柽柳新品种耐盐能力试验研究

东柽1号和东柽2号是东营市林业科技人员选育的柽柳新品种,具有干性强、枝繁叶茂、生长期长、花量少、绿化美化效果好等特点。本文以中国柽柳为对照,对东柽1号和东柽2号在6个土壤含盐梯度4g.kg-1、8g.kg-1、12g.kg-1、16g.kg-1、20g.kg-1、25g.kg-1下进行了耐盐栽植试验,调查栽植成活率和生长量。结果表明东柽1号、2号耐盐力优于中国柽柳,在土壤含盐量8g.kg-1以下,生长正常。土壤含盐量达20g.kg-1时,东柽1号、东柽2号的造林成活率达50%和46.6%,苗高生长量为80cm和92cm,地径生长量为1.3cm和0.9cm。     

太行山区核桃楸优良无性系选育研究

以55个核桃楸无性系为试验材料,进行苗高、地径等性状的方差分析,并估算出其遗传相关和遗传力及指数选择等遗传参数。结果表明:5年生核桃楸优树的优良无性系分别为1-6号、河南1号、河南2号。这3个核桃楸优良无性系苗高和地径的遗传力分别为0.72和0.76,苗高和地径遗传增益分别为23.90%和36.04%。核桃楸优良无性系的苗高和地径受到亲本优树选择影响非常有效,优良无性系的选育非常成功。     

紫椴优良无性系的初步评价

通过对扦插生根率高的 7个紫椴无性系和对照无性系生根力、苗木生长等指标的比较与评价以及主要性状遗传参数的估算得知 :不同无性系的遗传基础存在差异。这 7个无性系的苗高、地径均比对照高出很多 ,无性系间的高、径变幅较大 ,树高和地径的遗传力分别为 83.6 %和 86 .8% ,生根率遗传力为 90 .2 % ,这充分说明了遗传的稳定性。其中以编号为 0 0 86、0 0 0 6、0 0 12、0 2 16这四个无性系各指标表现较为突出 ,初步认为是较优良的无性系。     

晋东南杨树品种苗期选育研究初报

选择了30个杨树无性系品种进行苗期试验,调查了其1 a的胸径、树高生长量,初步评价了30个杨树无性系的适应性。结果表明：杨树各无性系胸径、树高生长量均达到极显著水平;按分层聚类法将杨树品种分为4类,优良种和良种占到66%,其平均树高、胸径分别高出群体平均值9.18%,20.48%;群体无性系胸径遗传力为0.90,单株遗传力为0.76;树高遗传力为0.94,单株遗传力为0.84;胸径、树高无性系遗传增益分别为2.6%,6.3%.     

樟子松半同胞子代苗期测定

通过对白城市林木良种繁育场的樟子松15个半同胞家系子代3 a生苗高和地径生长量进行测定及分析,结果表明:不同半同胞家系子代的苗高和地径生长量差异均达到极显著水平(p0.01),15个家系中苗高大于对照的占73.3%,地径大于对照的占86.7%,苗高遗传力为59.1%,地径遗传力为66.7%。按子代苗苗高、地径生长量大于对照10%的标准筛选6个优良半同胞家系,其中,63号家系的苗高和地径生长最快,分别为12.02 cm和0.63 cm,6个家系的平均苗高、地径分别为10.75 cm、0.57 cm,与CK相比较,其遗传增益分别为22.32%、21.03%。     

弥渡云南松无性系种子园子代生长量遗传分析

对云南松无性系种子园93个无性系子代林9年生的测定表明:云南松无性系子代林生长量明显高于对照,无性系子代林的树高、地径、单株材积、冠幅和枝下高平均值分别超过对照9.79%、15.94%、49.17%、17.35%和7.64%,大于对照的分别有81个、87个、84个、85个和84个无性系子代。子代林树高、地径、单株材积和冠幅的广义遗传力较高,在6.80%～9.42%之间,而枝下高的较低(3.02%)。子代林的树高、地径、单株材积、冠幅和枝下高等诸性状间存在紧密的正相关,这些性状在各无性系间存在着极显著的差异,采用系统聚类法可将无性系分为优良、良好、一般、较差和劣质共5类。筛选出优良无性系有84、58、56、52、41、70、47、39、55、34、75、71、79、45、69、35、65、91、64、57、37、88和32共23个,其树高、地径、单株材积的平均实际增益分别为20.95%、27.51%和87.70%,遗传增益分别为1.58%、2.59%和6.64%;良好无性系有49、42、90、89、53、51、78、44、66、38、85、82、40、67、36、63、28、60、62、46、43、61、29、54、48、72、50、83、9、30、20、16、33和6号共34个,其树高、地径、单株材积的平均实际增益分别为14.12%、19.01%和57.89%,遗传增益分别为1.06%、1.79%和4.38%。     

半年生思茅松半同胞家系生长量调查研究

为了选择思茅松优良家系,对半年生9个家系和1个对照的造林苗木进行树高、地径观测。结果表明,所有家系的树高生长量和地径生长量均大于对照。方差分析结果表明,家系间树高生长量和地径生长量均存在极显著差异。树高生长量与对照相比,有7个家系差异达到极显著水平;地径生长量与对照相比,有8个家系差异达到极显著水平。     

南方型杨树新无性系生长对比试验研究

以5年生54个南方型杨树无性系为材料,对其胸径、树高和材积生长量进行对比分析。结果表明:不同杨树无性系胸径、树高均存在极显著性差异,且受遗传控制较强,广义遗传力分别为0.846 5和0.605 0,遗传变异系数分别为13.95%、3.25%。不同杨树无性系胸径、树高连年生长量呈先增长后降低的趋势,造林后第3年平均年生长量最大,5年生时林木材积累积量均处于快速增长阶段。杨树无性系LA09-N56、LA06-N30、LA09-N23、TN01-49具有树皮光滑、干形通直,落叶晚等特征,与目前湖区普遍应用的良种XL-80、XL-90、XL-75生长量相当,均表现优良,且适宜长江及洞庭湖区滩地生长。     

一年生卷荚相思无性系测定试验初报

在福建省漳浦中西国有林场对1年生的共21个卷荚相思性系和3个黑木相思无性系分别测定其树高和地径,对卷荚相思进行了差异显著性分析并得出树高和地径的遗传力。结果表明:选取其中3个卷荚相思优良无性系1年生时的树高、地径平均值分别达67.2222mm、12.6028mm,与所有参试的卷荚相思无性系相比,其遗传增益分别达到7.881%、10.25%,生长性状表现十分突出,具有广阔的推广应用前景。     

水曲柳种子园半同胞子代遗传测定及优良家系选择

水曲柳种子园10年生半同胞子代家系树高、胸径和材积之间差异极显著;在参试的15个家系中树高有13个超过对照,生长量最大的是对照的1.15倍。胸径均超过对照,生长量最大的家系是对照的1.41倍。材积均超过对照,生长量最大的家系是对照的2.40倍;树高、胸径、材积家系遗传力分别是0.11、0.40、0.20,以材积显著大于对照为主要依据,参考树高、胸径两性状的表现,综合评选出7、4、9号3个优良家系,分别比对照,树高提高12.4%~14.8%,胸径提高32.7%~41.1%,材积提高120%~140%。7号家系各项指标均排在第一位,为最优家系;从15个家系中选出1个、2个、3个优良家系,其实生后代10年生时,树高能获得0.7%~0.9%的遗传增益,胸径能获得5%~7%的遗传增益,材积能获得6%~8%的遗传增益。     

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.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.