笋用良种——黄甜竹在杭州落户

黄甜竹(Sinobambusa edulis Wen)是浙江省林科所开发研究的竹种资源之一。原产福建,野生。1984年3月引种310株,种子本所,面积5亩。1985年出新竹356株,1986年出新竹1214株,最粗胸径已达4.7厘米。黄甜竹笋期4月21日至6月9日,发笋率高,笋肉色白,味甜,品尝风     

黄甜竹生长发育规律初步研究

对黄甜竹生长发育规律进行了初步研究,结果表明:黄甜竹发笋期从4月中旬开始至5月上旬止,持续时间约25 d,出笋规律呈偏右正态分布。黄甜竹平均成竹率为61.36%,发笋前期和盛期成竹率相当。幼竹高生长历时45 d,高生长总量可达7～8 m。     

地形因子对黄甜竹引种栽培的影响

研究了不同坡位、不同海拔等地形因子对黄甜竹(Acidosasa edulis)引种栽培的影响。结果表明:1)坡位对黄甜竹的造林成活率、发笋数及平均胸径均有显著影响,造林第2年发笋数和竹高生长显著增加;2)生长在下坡位的黄甜竹,竹林平均胸径和平均高最高,而生长在中坡位和上坡位的竹林各项生长指标相对较低;3)坡位对黄甜竹生物量分布的影响较大,黄甜竹各构件生物量分配大小排序为秆 > 枝 > 叶;4)随着海拔高度的上升造林成活率、当年新发笋数、第2年新发笋数呈减小的趋势,平均胸径、平均竹高、单株生物量呈增加趋势。试验结果可为西南地区黄甜竹营林和推广提供理论参考。     

印度牡竹育苗试验初报

牡竹 Dendrocalamus Strictus Nees 是耐干旱贫瘠、耐盐碱、抗逆性强的优良竹种,可作纸浆、家具等用途。可在我国热带、南亚热带的干旱、半干旱地区引种栽培。1986年春播种后,经精心培育,成苗160株(丛),生长良好。180天苗平均高144厘米,底径7毫米。各因子间的关系分析如下:①出苗期天数、积温与出苗量成正相关,r=0.975,回归方程:(?)=-1225.5415-751.8117·logx_1+888.4231·logx_2。②原本和各分蘖单株的高生长天数与高生长量的r 值在0.956～0.990之间。③分蘖次数与高度:r=0.995,(?)=18.6420·e~(0.4247·x)。但是它们的高生长完成天数与高度则成负相关。r=-0.993,(?)=397.0725·e~(-0.0360·x)④分蘖次数与底径:r=0.984,(?)=0.6162·e~(0.6216·x)。⑤底径与高度;r=0.990,(?)=11.7861+17.7345·x。⑥分蘖次数与秆柄前端直径:r=0.962,(?)=-11.7714+42.3671·log x。⑦分蘖次数与根总长:r=0.957,(?)=3.4314+191.5384·log x。根的总长与秆高相近。r=0.994,(?)=24.2922·e~(0.0121·x)。文中众多的回归方程,揭示了牡竹实生幼苗的生长规律,在育苗条件相似的情况下,可用以预测预报牡竹幼苗的生长趋势,具有指导生产的实际意义。     

吊丝单笋期生长特性研究

为探明夏秋季笋用良竹吊丝单的笋期生长特性和提高竹笋单产,通过多年的定时定位测试,系统研究了该竹的林分笋期.竹丛笋期、出笋数量的时间分布,发笋与母竹基础的关系,退笋规律。成竹规律、幼竹生长的季节变化和昼夜变化节律及其与气象因子的关系。结果表明:①笋期15/6～18/10,历时126天,其中大暑至立秋为出笋盛期,发笋量占总数的40％。发笋数量的时间分布为偏正态。②丛发笋数随竹丛的增大而增加,r=0.99;株母竹发笋数随竹丛的增大而减少,r=—0.711。以丛留母13～15株的竹笋最有利于竹笋单产的提高。全林的丛发笋数和株发笋数分别为6.21和0.79株。③湿笋数与出笋数的相关系数r=0.783;全林退笋率14％,其中以盛期为低;退笋高度60cm以下,多在10～20cm之间,占54.1％。④高生长历期113天,累积生长量、日均生长量分别为894.1、7.91cm,其中昼夜分别贡献77.6％、212.4％。生长以立秋至白露期间为快,在1/3生长期内,生长量占2/3。夜间生长速率是昼间的三倍多。⑤高生长量(y)与日均温(x1),日温差(x2)、降雨(x3)间的回归方程式为y=2.729+0.268x1—0.184x2+0.032x3,其中湿度的影响达显著水平。复相关R=0.463。     

地面覆盖对黄甜竹生长影响的初步研究

采用厩肥、谷糠、稻草进行覆盖后,显著增加了出笋时间和出笋产量,其中以厩肥效果为最佳,笋期延长29 d;不同覆盖物对于黄甜竹的竹高存在显著影响,覆盖厚度对于竹高生长没有显著影响;覆盖物及覆盖厚度对黄甜竹的胸径生长没有显著影响。不同的覆盖材料对黄甜竹地上各部分生物量影响表现为:厩肥>谷糠>稻草,而且秆部生物量均大于枝叶部生物量,生物量在地上各部分的分布是不均匀的。     

黄甜竹合理经营密度研究

在立地条件和经营管理措施基本相同的黄甜竹林分中,应用随机区组试验方法建立4种不同结构的黄甜竹样地,并测定不同立竹密度发笋数、成竹数、成竹率等指标,不同密度试验结果表明:经营密度为10500株·hm~(-2)时,林分生产力高,笋产量迭16010kg,新竹率达73%,竹径达4．86cm,经济效益好。     

连江县黄甜竹笋用林不同施肥效果研究

通过对黄甜竹幼林进行不同肥料施肥试验,采用合理的施肥措施,调查出笋成竹、竹高、竹径生长效果,结果表明:施肥对竹林生长均有较大的促进作用,不同的肥料对出笋成竹、竹高、竹径生长等方面促进效果不同.并总结出一套切实可行的经营黄甜竹施肥技术措施,为本地黄甜竹的丰产培育提供科学依据.     

利用早期笋培育毛竹大径材试验初报

利用早期笋培育毛竹大径材,试验表明:①培客土、施肥料与不培土不施肥的新竹胸径增加不显著,处理之间F=1.150.05(4,12)(3.49);②笋体高径比越小的笋留养的新竹胸径越大,其线性方程如下:培土、施尿素:y=-7x+32.6;培土、施复合肥:y=-2.0949x+20.445;培土、施磷酸二氢钾:y=-0.5886x+15.984;培土施尿素加磷酸二氢钾:y=-0.2.5x+21.4;对照:y=-1.5262x+18.577;③早期笋留养新竹胸径南北走向大于东西走向,且差异显著,t=2.943>t_(9)0.05(2.262)。     

不同管理措施对黄甜竹生长的影响

黄甜竹是高产、优质的笋用竹种。试验分析了不同抚育管理措施对黄甜竹发笋数、成竹数及生长的影响。结果表明,松土除草配合施用生物有机肥对发笋数、成竹数及平均胸径、平均竹高等促进效果最好。     

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.