光箨篌竹出笋成竹规律的研究

采用固定样地观测和随机样地调查相结合的方法,分析了光箨篌竹的出笋成竹规律以及不同径级竹笋和不同密度林分的出笋变化规律,进而分析了气象要素、立地条件和林分结构对出笋质量的影响,上述研究结果将为短周期工业用竹林的营建与培育提供依据。     

光箨篌竹竹笋幼竹生长规律的研究

对24株固定竹笋定时观测材料进行分析,表明了光箨篌竹竹笋幼竹的一些生长节律,阐述了出土期、生长级、林分密度和气象要素对竹笋成竹的影响,进而揭示了时进程类型与天气、气温和湿度的关系,探讨了它们在生产中的应用。     

刚竹属竹种笋期生长特性初步研究

本文对刚竹属竹种新造林笋期出笋、成竹、“竹笋～幼竹”高生长特性作了研究,并采用关联度分析法研究了“候”平均气温等气象因素对“竹笋～幼竹”高生长的影响。     

光箨篌竹笋期生长规律初步研究

本文对光箨篌竹笋期的出笋规律、成竹规律以及竹笋的生长发育规律进行了研究。初步认为,光箨篌竹林分的母竹立竹度一般应保持在2500株/亩左右、Ⅰ～Ⅱ级母竹株数保持在40％以上时,才能保证林分的优质高产与稳产;抽枝成竹历期长短受竹笋笋级大小、出土早晚或立地环境条件的影响可相应延长或推迟2～4d左右,一般历时25d,竹笋开始抽枝成竹时的高度一般为5m左右;竹笋在生长发育高峰期明显受到气候因子的影响,尤其是对气温更为敏感。     

石竹笋生长规律研究

为探讨石竹笋长成幼竹的生长规律及后期的生长特征,对福建省上杭县天然石竹林竹笋的日高生长量、成竹高度、产笋量、地径、高度和节间长度等进行连续33 d的观测。结果表明:竹笋长成幼竹的高生长模式方程为:H=100/(1+17.53556 e-0.18864 t)。最大生长速度的生长期为15.18 d。产笋前期笋地径大,高度大,单株竹重,但笋期短,数量少;产笋中期笋地径中等,冠层低,但笋期长,数量多。节间长与节数关系类似抛物线,拟合方程为:y=-0.0789 x2+2.9004 x-3.0825。分析节间生长和笋期规律,合理确定竹笋留养时期:培育速生丰产林以中期留养为好,而培育大径竹则以前期留养为好。     

王朗自然保护区引种竹笋：幼竹期异速生长规律的研究

本文以王朗1985年大熊猫主食竹类引种试验以来,筛选出的四个适应性最强的种:石棉玉山竹(Yushania lineolata)、青川箭竹(Fargesia rufa)、糙花箭竹(Fargesia scabrida)和冷箭竹(Bashania fangiana)及本地缺苞剪竹(Fargesia denudata)作材料,研究了各竹种当年生笋、一年生幼竹和二年生成竹的秆、枝、叶、箨和单株间以及与竹笋——幼竹期高径(D~2H)生长间的异速生长常数K的变化规律,建立了数学模型,并对竹笋到一年生幼竹的各器官(组分)的K值进行相关性研究,探讨在竹笋——幼竹期K值的变化规律。另外还根据笋秆K_s值与缺苞箭竹比较,确定各竹种竹笋——幼竹期的长短及进入稳定加固期的时间,评价各竹种的适应性能力。结果表明:笋期秆异速生长最显著的是糙花箭竹,顺次为石棉玉山竹、青川箭竹和冷箭竹。一年生幼竹器官异迷生长缺苞箭竹向多枝性发展,青川箭竹枝与秆之间生长近似于线性关系,秆、枝、叶和单株间成均衡性生长,而石棉玉山竹、糙花箭竹和冷箭竹则向少枝大秆型发展。单株生物量累积速度的主要因子是叶的生长,其次是秆、枝。二年生成竹的K值出现明显的变化,各竹种经竹笋——幼竹期进入稳定加固期的时间是不同的,石棉玉山竹和青川箭竹一般为1—2年,糙花箭竹和冷箭竹约为2—3年。竹笋——幼竹期K值因种和不同生长年龄而发生变化。笋期(秆、单株)生长速度与其笋成竹的秆、枝、叶和单株K值成负相关,但是笋期异速生长越快,则竹笋——幼竹期越长,进入稳定加固期较晚。对于可塑性强, 较为敏感的竹笋——幼竹来说,时间经历越长,对环境的生态适应能力将会变大。生产实践中,可用笋期秆异速生长常数K_s的大小来确定各竹种其笋进入幼竹和成年稳定后的适应能力及适应程度。表中的数字模型可用来预测生物量。     

竹笋夜蛾的防治

竹笋夜蛾,是我国竹产区笋期主要害虫之一,幼虫蛀食毛竹、淡竹、刚竹、桂竹的竹笋,被害率一般可达30%～40%,被害竹笋不能成竹,即使成竹亦常断头折梢,竹材干脆易折,失去效用.     

寿竹出笋及竹笋-幼竹高生长规律

通过对寿竹出笋和幼竹高生长阶段的调查,研究了寿竹笋期的生长发育规律。结果表明,寿竹出笋从5月初开始,出笋盛期为5月8日到5月21日,盛期出笋数量占84.7%,出笋全部持续时间约30天。寿竹的高生长持续60天左右,高生长符合Logistic模型。引起寿竹退笋的主要原因是虫害,占退笋的比例74.7%,造成退笋的主要害虫是竹笋泉蝇。该地区寿竹整个出笋期平均成竹率仅为11.7%。     

第七讲 竹类害虫及其防治

竹类在生长和利用过程中,也会受到各种害虫的危害,导致减少和降低竹材的产量和质量。常见的竹类害虫种类较多,现分为蛀笋、食叶、吸液汁、竹材等害虫,分别介绍。一、笋期害虫危害竹笋的害虫主要是竹笋夜蛾、竹笋蝇、竹象等,以幼虫蛀食笋肉,被害竹笋不能成竹,影响竹林产量。1.竹笋夜蛾:分布各竹产区。成虫灰褐色,长20毫米,前翅基部及顶部有三角形深色斑,后翅黄褐色。幼虫头部橙红色,体紫褐色,体背有淡色纵线(图1)。幼虫蛀竹笋,     

黄纹竹驯化试验

2013年将野生黄纹竹在浙江省丽水市进行驯化试验,结果表明:黄纹竹出笋规律呈偏正态分布,出笋期在3月底至6月底;成竹率高达94.02%,退笋率为5.98%,退笋高度在40 cm以下不同高度均有发生且主要集中在10~30 cm;黄纹竹笋—幼竹高生长呈缓慢—快—慢的过程,分初期、盛期和末期3个时期,笋—幼竹高生长夜间生长量是昼天生长量的1.17倍,但生长末期昼天生长量高于夜间生长量;野生黄纹竹耐干旱,造林成活率高,造林第二年平均每株发笋数3株,成林快。     

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.