龙竹,甜龙竹植苗造林技术的研究

在云南省西盟县对龙竹、甜龙竹植苗进行了不同整地方式、造林密度、施肥种类和数量、封顶等内容的造林技术试验研究。结果表明：在同等立地条件下，龙竹的生长发育状况优于甜龙竹；全面整地和带状整地消除了杂草、灌木与竹子争水争肥争光的矛盾，较好地改善了土壤理的理化性质，有利于竹子的生长发育；每ｈｍ＾２配合追施尿素９９ｋｇ、普钙１６５ｋｇ、Ｋ２ＳＯ４３３ｋｇ有利于竹子的直径生长和多发笋；适宜的封顶可去除竹子的顶端     

龙竹,甜龙竹植苗造林技术研究

在云南省西盟县岳宋竹要基地，进行了龙竹、甜龙竹植苗林技术的研究，选择６个造林技术分３个水平进行正交试验。结果为：竹种、整地方式、造林密度、施Ｎ肥、Ｐ肥、Ｋ肥、土高度等７个因素对竹子的直径生长均有极显著影响；竹种、整地方式、施Ｎ肥、封顶高度对发笋量有极显著影响；施Ｐ肥、Ｋ肥对发笋量有显著影响。     

龙竹、甜龙竹植苗造林技术研究

在云南省西盟县岳宋竹林基地,进行了龙竹、甜龙竹植苗造林技术的研究,选择6个造林技术分3个水平进行正交试验。结果为:竹种、整地方式、造林密度、施N肥、P肥、K肥、封顶高度等7个因素对竹子的直径生长均有极显著影响;竹种、整地方式、施N肥、封顶高度对发笋量有极显著影响;施P肥、K肥对发笋量有显著影响。     

龙竹高产栽培技术

龙竹为大型丛生竹,具有重要的经济价值和生态价值。文章试验研究了育苗方式、坡向、肥料种类以及造林整地方式对龙竹生长的影响。结果表明：与其他育苗方式相比,龙竹组培苗造林竹株生长好,竹材产量高;龙竹适宜栽植于阴坡,采用全面整地法,在造林后的前4年每年施用适量的氮磷钾复合肥,可培育出高产的龙竹林。     

巨尾桉纸浆材丰产栽培技术研究

本研究选择整地、施肥、密度三个主要栽培措施作试验因素，进行正交试验。结果分析表明：整地、施肥、密度对巨尾桉生长的影响程度依次为密度＞整地＞施肥。密度是巨尾桉纸浆材丰产的关键措施；在较好的立地上，巨尾桉纸浆材丰产林的栽培可采用块状整地方式，规格为５０×５０×５０ｃｍ；每穴施基肥：滤泥２．５ｋｇ＋复合肥０．６６５ｋｇ；造林密度为１６６５株／ｈｍ２。     

巨尾桉纸浆材丰产栽培技术研究

本研究选择整地，施肥，密度三个主要栽培措施作试验因素，进行正交试验。结果分析表明；整地，施肥，地巨尾桉生长的影响程度依次为密度〉整地〉施肥。密度是巨尾桉纸浆材丰产的关键措施；在较好的立地上，巨尾桉纸浆材丰产林的栽培可采用块状整地方式，规格为５０×５０×５０ｃｍ，每穴施基肥：泥２；５ｋｇ＋复合肥０．６６５ｋｇ；造林密度为１６６５株／ｈｍ＾２。     

版纳甜龙竹产笋量的调查研究

对版纳甜龙竹在不同地区、坡向、坡位、坡形、海拔等立地因子以及立竹密度、季节的鲜笋产量进行实地调查。结果表明,各项因子对版纳甜龙竹鲜笋产量均有一定的影响。阳坡(光照多)、下坡(水分养分充足)、立竹密度适中有利于版纳甜龙竹的发笋,生长在海拔1 100~1 500 m的鲜笋产量较高。版纳甜龙竹鲜笋具有较高的经济价值和营养价值,通过调查较好地掌握了版纳甜龙竹发笋规律,对经营版纳甜龙竹竹林和鲜笋起到良好的指导作用[1]。     

丛生竹枝条扦插造林、埋节造林技术研究

根据气候和土壤条件的不同,分别在双江县坝糯竹林林场和勐库忙那林场,西盟县岳宋乡,新平县平甸乡等四个试验点,对黄金间碧玉、油簕竹、绵竹、勃氏甜龙竹、大叶慈竹、龙竹、版纳甜龙竹、野龙竹、慈竹、云南龙竹等10个竹种,进行枝条扦插造林、埋节造林试验,从立地条件、竹种、种源、母竹运输贮存、造林整地、造林密度、造林时间、促进生根剂、抚育管理等方面进行试验研究,得出了七点结论。     

丛生竹枝条扦插造林,埋节造林技术研究

根据气候和土壤条件的不同，分别在双江县坝糯竹林林场和勐库忙那林场，西盟县岳宋乡，新平县平甸乡等四个试验点，对黄金间碧玉、油勒竹、绵竹、勃氏矩龙竹、大叶慈竹、龙竹、版纳甜龙竹、野龙竹、慈竹、云南龙竹等１０个竹种，进行枝条件扦造林，埋节造林试验，从立地条件、竹种、种源、平竹运输贮存、造林整地、造林密度造林时间、促进生根剂、抚育管理等方面进行试验研究，得出了七点     

火炬松建筑材林栽培模式研究阶段报告

１９９２～１９９４年的试验结果表明，在低丘中层红壤上栽植火炬松，施过磷酸钙０．５ｋｇ／株效果显著；但块状整地（１．２ｍ见方）与全面整地、４０ｃｍ×４０ｃｍ×３０ｃｍ穴与７０ｃｍ×７０ｃｍ×６０ｃｍ穴以及每年５月幼林抚育１次与每年２次的其生长差异均不显著。根据上述试验结果以及对浙江与皖东丘陵现有火炬林分生长分析，初步认为火炬松建筑材林合理栽培模式为：造林密度１６６５株／ｈｍ２，１ｍ见方块状整地，挖４０ｃｍ×４０ｃｍ×３０ｃｍ植树穴，施基肥过磷酸钙０．５ｋｇ／株，造林当年抚育２次，第２～３年每年１次。上述栽培模式经经济分析表明：造林成本不到旧栽培模式（全垦大穴、大量施肥、每年抚育２次以上，造林密度１０５０株／ｈｍ２）的１／２，而收入增加２／３，旧的栽培模式造林无盈利可言，而新的栽培模式主伐时可盈利１２７５０～２３２５０元／ｈｍ２。     

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.