不同海拔高度松墨天牛生物学特性研究

采用室内饲养观察法、饵木诱集观察法、样木解剖调查法和诱捕器诱集调查法,对松墨天牛在恩施市海拔400～1 200 m处的发生期进行了调查研究。结果表明:松墨天牛成虫在恩施市发生期为4月下旬末～10月中旬;随着海拔的升高,成虫羽化高峰期逐渐推迟,海拔400～600、600～800、800～1 000 m、1 000～1 200 m天牛羽化高峰期分别在6月下旬、7月上旬、7月中旬、7月下旬。不同海拔高度该虫均为1年发生1代,都以低龄幼虫和老熟幼虫分别在韧皮部和木质部的虫道内越冬,但在不同海拔高度条件下该虫各虫态发生期不同,低海拔400m处各虫态的发生期要比高海拔1 200 m处提前30 d左右。恩施市为典型的盆地气候,松墨天牛成虫发生期差异显著,防治适期不一,该研究为该市松墨天牛的防治和预测预报提供了可靠的理论依据。     

海拔高度对‘香玲’核桃生长结果习性的影响

以引种的‘香玲’核桃为试材,对襄阳市保康县不同海拔区域的核桃生长结果习性进行调查研究,结果表明:在相同的生长年限下,引种的‘香玲’核桃平均树高、平均地径在海拔700~800 m呈现最大值,单株冠幅面积和单株结果数量在600~700 m呈现最大值,700~800 m产量最不稳定,病果率在海拔600~700 m最低;在海拔800 m以上,随着海拔的升高,树体平均高度、树体平均地径、单株冠幅面积和单株结果数量均呈现下降的趋势。因此,保康县600~800 m区域是最适宜‘香玲’核桃引种的区域。     

灵山正路花椒良种繁育技术研究

本文以凉山州冕宁县灵山正路椒为试材,研究了部分影响产穗量、发芽率以及嫁接成活率的因素。包括定干高度、修剪强度以及采穗量对灵山正路花椒产穗量的影响;种子储藏、催芽方式以及采种、播种时间的不同对种子发芽率的影响;砧木、嫁接时间、嫁接方式以及接穗木质化程度的不同对嫁接成活率的影响。经过连续四年的单因素对比试验,提出了"50 cm定干高度、中剪、采四留六"产穗圃营建技术,"牛粪或草木灰拌种法、开水烫种催芽、春季播种"实生苗繁育技术,"劈接技术,野生竹叶椒砧木,春分嫁接,接穗木质化"良种无性嫁接技术。     

不同海拔对试验地的中泰南五味子生长的影响研究

对西双版纳州普文试验林场和大渡岗乡大干坝村试验地不同海拔的中泰南五味子生长量进行调查。结果表明,2015—2018年,不同海拔试验地中,中泰南五味子的地径、藤长生长量均存在极显著差异;普文试验林场的生长量略高于大渡岗大干坝的;海拔800 m的生长量在不同时间及不同试验地均略高于海拔1 200 m的;海拔1 000 m的生长量均优于海拔800 m、海拔1 200 m的。提出在西双版纳境内,中泰南五味子应选择海拔在1 000 m左右地块种植生长最佳。     

立地条件对红花椒产量的影响

立地条件的不同(海拔、气温、土壤),决定了种植花椒的品种,规模、经营管理技术的不同。喜德县红花椒(大红袍和正路椒)为主,海拔、土层厚度的变化,对花椒的产量影响较大。随着海拔的升高,会逐渐降低。海拔2 600 m以上,虽然花椒生长极端气候的影响较大,但土层厚度越大,更有利于花椒的生长。     

金佛山方竹垂直分布及低海拔异地引种后笋产量和品质

文章实地调查了大娄山山脉金佛山方竹的垂直分布,并探索其在低海拔异地发展的可能性。2008年至2020年,以单竹丛为单位,对栽种在海拔2 000、1 356、1 352、1 130、1 080、720和658 m的金佛山方竹出笋情况进行逐年观测,比较其笋产量及笋营养元素含量与原生地的差异。结果表明：1）大娄山脉金佛山方竹天然资源主要分布在大娄山山脉海拔1 600~2 200 m,上线海拔2 227 m （柏芷山）,下线海拔1 400 m左右,每年自然繁衍海拔下延1~3 m,个别植株通过山体滑坡及沟谷流水瀑布等外力带至海拔1 350 m或1 150 m处,并小面积蔓延;2）在海拔1 356~658 m的原生地低海拔区及异地引种金佛山方竹,除海拔658 m处的笋产量和氨基酸含量低于原生林外,其他引种地的笋产量和笋品质指标均与原生林差异不大。研究结果表明,通过选择优良单株,可以在海拔658 m以上沟谷背阴地的疏林下发展金佛山方竹。     

2种野鸦椿的生长适应性与栽培对比研究

以落叶类野鸦椿与圆齿野鸦椿为研究对象,在人工栽培下比较物候期、生长量、果实产量等方面的差异,结果表明2种野鸦椿物候期与生长适应性差异极大。圆齿野鸦椿四季常青,挂果期超长,而落叶类野鸦椿冬季落果落叶;圆齿野鸦椿适生在海拔700 m以下,而落叶类野鸦椿适合生长在700 m以上。在海拔较高的地区,落叶类野鸦椿长势较好,圆齿野鸦椿长势较差且出现冻死现象;在低海拔地区,圆齿野鸦椿长势较好,其生长指标与果实产量均显著高于落叶类野鸦椿。     

武夷山不同海拔土壤和大气温度的时空变化特征

选取武夷山国家级自然保护区内5个海拔(1 200、1 400、1 600、1 800和2 000 m)的黄山松样地，对近地面大气(0～12 cm)和土壤(-6～0 cm)温度进行17个月的连续监测，以期揭示近地面大气和土壤温度的时空变化规律和温度梯度变化特征。结果表明：土壤温度显著高于大气温度(P<0.05),土壤和大气温度存在月份和季节变化规律。土壤和大气温度在不同海拔中存在显著差异(P<0.05),在海拔1 200 m最高，分别为12.85±5.15和12.45±7.25℃;海拔2 000 m最低，分别为10.26±4.99和9.58±6.56℃。土壤和大气年平均温度梯度变化分别为3.24和3.59℃。不同季节存在不同的温度变化特征，并且黑夜的土壤和大气温度梯度变化高于白天。土壤和大气温度存在时空变化规律，并且不同季节和昼夜变化对温度梯度变化存在影响。     

海拔梯度对多花黄精生长及多糖含量的影响

以毛竹林冠下种植的多花黄精根茎繁殖苗为研究对象,探讨不同海拔梯度(150~300、300~450、450~600、600~800、800~1000、1000~1200 m)对多花黄精生长及多糖含量的影响。结果表明:不同海拔梯度对多花黄精生长影响较为显著,多花黄精的生长量和多糖含量随海拔升高呈逐渐下降趋势,以海拔150~600 m范围内多花黄精的生长量和根茎质量较高,2年生多花黄精的保存率、地径、高度、根茎总产量、根茎多糖含量的平均值分别达91.6%、0.57 cm、62.5 cm、6109.29kg·hm-2、13.5%;选择海拔600 m以下区域范围内的毛竹林冠下种植多花黄精较适宜。研究结果对多花黄精最适栽培区域选择具有一定参考价值。     

保康县核桃林下套种模式分析

为找出适宜湖北省鄂西核桃林下套种模式,作者调研分析目前襄阳市保康县林农的种植习惯和核桃林下种植主要模式、经济效益及各种植模式对核桃树体生长的影响。结果表明:目前全县核桃林下套种模式主要有核桃+药材、核桃+蔬菜、核桃+茶叶、核桃+苗木4种套种模式,其垂直分布范围分别为900 m左右、600~1 000 m、600 m左右和400 m左右区域,各模式各有优缺点,适宜在不同海拔区域推广不同的模式。     

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.