武汉地区引种灯台树栽培技术与速生因素研究

通过20a3次引种珍稀灯台树,证明灯台树在武汉地区引种成功,且生长迅速。当年苗期平均高生长达89cm。大树年平均高生长达1·2m,胸径1·12cm,大大超过桢楠、紫楠、白玉兰等其他珍稀种,很有开发利用价值。     

峦大杉引种造林试验

峦大杉经 12a的引种造林试验表明 :1年生苗平均高 2 0 5cm ,平均地径 0 37cm ;造林后第 12a林分平均树高 10 4～11 1m ,胸径 13 5～ 14 1cm ;造林初期生长缓慢 ,树高在第 2a后、胸径在第 4a后年生长量与本地杉木无显著差异 ;12年生的纯林与混交林树高、胸径值差异不显著 ;育苗与造林技术均容易掌握 ,具有重要的引种价值。     

美国岩榆和南方岩榆的苗期试验

在我国北亚热带安徽滁州琅琊山林场进行美国岩榆和南方岩榆引种育苗试验,旨在验证其对当地土壤和气候条件的适应程度,为进一步引种与推广作准备.结果表明:岩榆、南方岩榆发芽率分别为76%、54%;两种榆树苗木前期生长均较慢,100 d时,岩榆苗木平均高为16.5 cm,南方岩榆13.5 cm.它们的速生期始于7月份,且峰值均出现在8月,到11月下旬生长均逐渐停止,落叶时间均普遍比作对照的白榆迟7-14 d.岩榆1 a生苗木平均高61.5 cm,最高达96 cm;南方岩榆1 a生苗木平均高53.5 cm,最高达94 cm;白榆1a生苗木平均高73 cm,最高达112 cm.南方岩榆约0.3%苗木有尺蠖危害,而岩榆、白榆及南方岩榆混生苗没有受此危害.     

优良观赏树种大叶樟引种苗期试验

2002～2004年在南京、江都、无锡等地引种大叶樟试验表明,苗期高生长呈现单峰形,5～6月开始生长,7～9月速生,7月呈现峰值,10月生长下降后趋于停滞.生长与气温、湿度和光照关系密切,显著或极显著正相关.苗期1～2 a与当地香樟一样在-7℃极端低温下有较重冻害,但冻害轻于香樟;3 a时苗木冻害显著减轻,5 a时未见明显冻害.1～2 a生苗树高年均净生长量达0.83～0.99 m,3 a达0.95 m,5 a达0.85～0.98 m,显示出速生潜力.5 a生苗平均树高达4.26～4.88 m,胸径5.8～6.5 cm,冠幅2.0～2.5 m,已达城市行道绿化和园林绿化出圃标准.苗木耐湿性较强,在地面淹水20 h,深10 cm的情况下,1 a移植苗未见受害.引种苗期1～3 a和幼龄初期5 a未见明显病虫害.由此认为,大叶樟是樟科生长适应性较强的常绿观赏阔叶树,可在南京及苏南地区城市森林建设、园林绿化中扩大应用.     

南京引种邓恩桉、冈尼桉苗期试验初报

在我国北亚热带江苏南京南郊进行邓恩桉和冈尼桉两个耐寒桉树的引种试验 ,苗期研究结果表明 ,夏雨型种邓恩桉播种后出苗较快 ,3月中旬播种 ,一般 10d开始出苗 ,2 0d时苗木基本出齐 ;冬雨型种冈尼桉播种后出苗较迟 ,一般 2 0d才开始出苗 ,4 0d时苗木基本出齐。两种桉树苗木前期生长较慢 ,10 0d时 ,邓恩桉平均苗高 16 4cm ,冈尼桉仅 5 1cm。邓恩桉于 7月开始速生 ,8月呈现峰值 ,至 11月下旬逐渐停止生长。 1a生苗平均高 1 6 3cm ,最高可达 2 5m。冈尼桉不适应南京地区夏季高温 ,在遮阳网覆盖遮荫降温条件下 ,7月陆续死亡。邓恩桉对低温有一定的适应性 ,在冬季 - 7℃自然低温下 ,仅叶片边缘及少量嫩芽出现轻度寒害 ,显示出引种潜力     

福建柏和杉木人工林细根生产力、分布及周转的比较

对福建三明福建柏和杉木人工林细根生产力、分布及周转进行了为期 3年的研究 ,结果表明 ,福建柏年均细根生物量达 389 7g·m- 2 ,是杉木林 (2 77 2g·m- 2 )的 1 4 1倍 ;活细根年均生物量达 2 16 3g·m- 2 ,是杉木林(14 8 4g·m- 2 )的 1 4 6倍 ;<0 5mm细根生物量 (2 4 2 2g·m- 2 )则是杉木林 (12 4 7g·m- 2 )的 1 94倍 ,其占总细根生物量比例 (6 1 2 % )比杉木林 (4 5 0 % )的高出 16 2 %。福建柏和杉木细根垂直分布在 0～ 10cm土层差异最大 ,该层福建柏总细根密度 (14 4 2g·m- 2 )是杉木 (70 2g·m- 2 )的 2 1倍。福建柏林活细根生物量 1年只出现 1次峰值 (3月 ) ,而杉木林活细根则出现 2次 (3月和 9月 )。福建柏不同径级细根第 1年分散速率及分解系数均低于杉木的。福建柏林细根年净生产量 (32 0 2g·m- 2 a- 1 )和细根年死亡量 (32 6 5g·m- 2 a- 1 ) ,分别是杉木林 (2 5 1 3和 2 4 9 2g·m- 2 a- 1 )的 1 2 7倍和 1 31倍。福建柏细根年均周转速率为 1 4 8a- 1 ,低于杉木林的 (1 6 9a- 1 )。福建柏和杉木细根生物量分别仅占其乔木层生物量的 1 70 %和 1 18% ,但细根净生产力却分别占其乔木层总净生产力的 19 84 %和19 2 1% ,细根年死亡量分别占地上部分凋落物量的 4 8 74 %和 5 1 0 0     

宁夏中部干旱带梭梭人工造林试验研究

在宁夏选择不同立地条件的造林试验区,进行了梭梭(H.ammodendron)人工造林试验研究,通过2年的调查研究,在地下水位较高,苗期管理规范的试验区,当年平均株高达47.98cm,平均地径0.53cm,第二年平均株高达93.21cm,平均地径0.91cm。梭梭当年造林根系生长快,第二年地上部分生长迅速,株高和地径增长率为94.3%和71.6%。沙质土壤平均成活率达79.25%,保存率达66.25%,说明我区部分地区立地条件和生态环境适宜梭梭生长,可以进行人工造林。     

沙区樟子松苗期干物质的研究

通过对樟子松 1年生留床苗、2年生留床切根苗、2年生移植 (未切根 )苗的干物质比较 ,结果表明 :含水量 ,2年生切根苗 <未切根 2年生苗 <1年生苗 ;生物量 ,2年生切根苗各部位干物质量 >2年生未切根苗各部位干物质量 >1年生苗各部位干物质量 ,1、2年生苗干物质主要由地上部分组成。研究结果为 :切根苗质量超过未切根苗 ,一级苗数量多于未切根苗 ;苗木在苗期积累了大量干物质 ,根系及径生长旺盛 ,樟子松在苗期非常适合沙区     

红松生长发育规律研究

红松在1a中高生长主要分为三个阶段，开始生长期(5月初-5月20日)，生长速生期(5月20日-6月5日)，生长末期(6月5日-6月20日)，部分红松二次高生长出现在8月5日-9月10日。各期高生长与各期积温关系密切。15a红松高生长分为缓苗期(3a生苗造林后4a内)、加快期(造林后5—8a内)、速生期(造林后9—12a)。速生期内，树高连年生长量平均达40cm，最大者达90cm。树高近5a定期生长量及15a总平均生长量均是北亚区大于南亚区，南亚区大于中亚区，但是，近3a、2a、当年生长量都是南亚区大于北亚区、北亚区大于中亚区。     

不同造林方式下闽楠幼林根系性状分析

以3种造林方式(18 a杉木林下套种闽楠、闽楠纯林、闽楠与杉木混交林)营造的闽楠试验林为对象,分析造林2 a后幼林生长情况,利用Win-RHIZO根系分析系统比较不同造林方式闽楠根系性状的差异。结果表明:杉木林下套种闽楠的平均地径、最大冠幅、苗高、枝下高、单株总根长、总表面积、根系总体积、根深和平均根幅均最大,依次为11.60 mm、61.33 cm、115.56 cm、32.42 cm、1269.13 cm、376.75 cm^2、9.32 cm^3、47.50 cm、48.42 cm;3种造林方式下闽楠单株根总长度均在根系直径0 mm4.5 mm、0.5 mm-2的林下套种方式最适合闽楠生长。     

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.