江西安福不同类型毛竹林土壤入渗与贮水特征

对江西安福毛竹林类型(毛竹纯林、竹阔混交林和竹杉混交林)土壤入渗与贮水特征进行研究,以中亚热带常绿阔叶林和杉木纯林为对照。结果表明,毛竹纯林0～60 cm土壤初渗率、平均渗率、稳渗率和前60 min渗透总量分别为1.64 mm/min,1.31 mm/min,1.23 mm/min和157.10 mm,均小于毛竹混交林。不同类型毛竹林土壤渗透性能均随着土层深度的增加而降低。用Kostiakov模型进行不同类型毛竹林不同土层深度的土壤入渗过程拟合,其决定系数为0.602 1～0.949 6,均达到显著水平。不同类型毛竹林土壤贮水能力差异显著,0～60 cm土壤滞留贮水量在27.47～45.40 mm,毛竹混交林大于纯林。不同类型毛竹林土壤贮水能力均表现为随着土层深度的增加而减弱。毛竹纯林的土壤入渗和贮水性能劣于阔叶林和杉木林,而混交经营有利于改善毛竹林土壤结构,从而提高毛竹林水源涵养功能。     

蕉岭长潭省级自然保护区不同林分类型土壤水分物理性质研究

对广东省蕉岭长潭自然保护区的阔叶混交林、马尾松林、杉木林、毛竹林、针阔混交林等五种典型林分的土壤水分物理性质进行了研究,结果表明：（1）五种林分类型土壤自然含水量、毛管持水量、最小持水量的排序为毛竹林〉针阔混交林〉马尾松林〉杉木林〉阔叶混交林;非毛管孔隙度和非毛管持水量的排序为针阔混交林〉阔叶混交林〉杉木林〉马尾松林〉毛竹林。（2）五种林分的非毛管孔隙度;阔叶混交林、杉木林、针阔混交林的总孔隙度;阔叶混交林的毛管持水量、最大持水量、最小持水量、非毛管持水量;针阔混交林的自然含水量、毛管持水量、最大持水量、最小持水量、非毛管持水量都是随着土层深度的增加而减少。阔叶混交林、毛竹林、杉木林、针阔混交林的土壤容重是随土层深度的增加而增加。（3）同一土层不同林分间的容重、孔隙度、自然含水量、最大持水量、毛管持水量、非毛管持水量和最小持水量都没有显著差异,而同一林分的物理性质和持水特性在不同土层之间存在显著差异。     

缙云山自然保护区4种森林类型林地土壤的持水特性研究

对缙云山自然保护区的常绿阔叶林、针阔混交林、竹林、灌木林林地及农地(对照)土壤的物理性质、土壤水分的入渗性能进行了测定分析,结果表明:其林地(农地)表层土壤容重的顺序为,常绿阔叶林>针阔混交林>竹林>农地>灌木林;土壤非毛管孔隙度的顺序为,灌木林>针阔混交林>竹林>常绿阔叶林>农地。灌木林林地土壤的有效水分涵蓄量要明显大于其他的森林类型,其蓄水量是竹林的1.4倍,是农地的2.14倍。4种森林类型林地及农地土壤的水分下渗性能,其层间稳渗率以腐殖质层>淀积层>母岩层;在土壤层,以竹林和农地的水分初渗为高。灌木林林地土壤的水分渗透性能极强,其初渗值达到了10.169 mm/min。从土壤水分的入渗性能来看,灌木林涵养水源和理水调洪的功能要远大于其他森林类型,针阔混交林要优于常绿阔叶林,而竹林最差。然而,对于遭遇短历时较高强度的降雨而言,竹林的理水调洪作用可能略好于针阔叶混交林和常绿阔叶林。     

缙云山自然保护区4种森林类型林土壤的持水特性研究

对缙云山自然保护区的常绿阔叶林、针阔混交林、竹林、灌木林林地及农地(对照)土壤的物理性质、土壤水分的入渗性能进行了测定分析,结果表明:其林地(农地)表层土壤容重的顺序为,常绿阔叶林＞针阔混交林＞竹林＞农地＞灌木林;土壤非毛管孔隙度的顺序为,灌木林＞针阔混交林＞竹林＞常绿阔叶林＞农地.灌木林林地土壤的有效水分涵蓄量要明显大于其他的森林类型,其蓄水量是竹林的1.4倍,是农地的2.14倍.4种森林类型林地及农地土壤的水分下渗性能,其层间稳渗率以腐殖质层＞淀积层＞母岩层;在土壤层,以竹林和农地的水分初渗为高.灌木林林地土壤的水分渗透性能极强,其初渗值达到了10.169 mm/min.从土壤水分的入渗性能来看,灌木林涵养水源和理水调洪的功能要远大于其他森林类型,针阔混交林要优于常绿阔叶林,而竹林最差.然而,对于遭遇短历时较高强度的降雨而言,竹林的理水调洪作用可能略好于针阔叶混交林和常绿阔叶林.     

中山市7种林分类型土壤涵养水源效能的初步研究

以马尾松、湿地松、大叶相思、竹林、杉木、针阔混交林、阔叶林等7种林分为研究对象,研究了中山市不同林分类型的土壤贮水能力和土壤渗透性能。结果如下:7种林分类型0～100 cm土壤最大持水量平均值为562.7 mm,以大叶相思和阔叶林这两种阔叶林分为最大、在600 mm以上,而杉木、湿地松和马尾松等针叶林较小、在510～536 mm之间;针阔混交林和竹林居中。土壤的初渗速度15.78～39.50 mm/min,稳渗速度2.08～4.40 mm/min;土壤入渗过程的回归方程表现为幂函数形式,回归系数R值均大于0.95,方程拟合效果好。     

广东流溪河5种林分的枯落物与土壤持水性*

文章以流溪河林场5 种不同林分为研究对象,分析其枯落物和土壤持水特性。结果表明：（1） 5 种林分枯落物持水能力表现为：荔枝（Litchi chinensis）林> 针阔混交林> 杉木林> 阔叶混交林> 毛竹 林;（2）5 种林分0 ~ 60 cm 土壤容重随土层深度增加而增大,60 cm 土层平均容重大小依次为：毛竹林< 针阔混交林< 阔叶混交林< 杉木林< 荔枝林;（3）5 种林分土壤总孔隙度平均大小依次为毛竹林> 针阔 混交林> 阔叶混交林> 杉木林> 荔枝林;（4）5 种林分土壤贮水量大小为毛竹林> 针阔混交林> 荔枝林> 杉木林> 阔叶混交林。总体而言,荔枝林枯落物持水性最好,毛竹林土壤持水性最强。     

冀北山地桦木林土壤水分物理性质研究

以4种不同桦木组成比例的林分类型为研究对象,比较其土壤水分-物理性质,结果表明:土层深度与容重呈正相关,落桦混交林土壤容重最大(1.14g/cm~3),桦木混交林最小(1.00g/cm~3);土壤孔隙度整体规律基本一致,随土层深度增加而减小,土壤毛管孔隙度、非毛管孔隙度、土壤总孔隙度均是黑桦纯林最大,分别为45.0%、9.6%、53.6%;土壤持水量(除桦木混交林规律不明显外)整体规律基本一致,随土层深度的增加而减小,土壤毛管持水量均值桦木混交林最大(43.2%),土壤最大持水量均值黑桦纯林最大(49.3%);土壤入渗速率与时间呈幂函数关系,初渗速率和稳渗速率规律一致,均是桦木混交林最大、桦杨混交林最小。     

杉木闽粤栲异龄复层混交林涵养水源功能

为揭示杉木闽粤栲异龄复层混交林涵养水源功能,2017年在福建沙县对4种保留密度的杉木闽粤栲异龄复层混交林的林分持水量、土壤物理性质和涵养水源功能进行研究。结果表明:与栽植前、杉木纯林相比,各异龄复层林土壤的0～20 cm土层,土壤密度分别下降8.86%、7.78%以上,土壤结构体破坏率分别下降15.12%、11.30%以上,0.25 mm水稳性团聚体含量分别提高12.55%、9.38%以上,非毛管孔隙度分别提高14.87%、10.76%以上,毛管孔隙度分别提高15.32%、11.68%以上,总孔隙度分别提高15.25%、11.53%以上;20～40 cm土层土壤的上述各项指标均表现出相同变化规律。与对照杉木纯林相比,林分总持水量增加218.312 t·hm~(-2)以上,提高14.68%以上;初渗速度增加13.29%以上,稳渗速度增加14.16%以上,地表径流系数降幅达10.34%以上。说明在杉木林中引入闽粤栲显著改善土壤的物理性质,提升林分的涵养水源功能。     

广东流溪河5种林分的枯落物与土壤持水性

文章以流溪河林场5种不同林分为研究对象,分析其枯落物和土壤持水特性。结果表明:(1)5种林分枯落物持水能力表现为:荔枝(Litchi chinensis)林针阔混交林杉木林阔叶混交林毛竹林;(2)5种林分0~60 cm土壤容重随土层深度增加而增大,60 cm土层平均容重大小依次为:毛竹林针阔混交林阔叶混交林杉木林荔枝林;(3)5种林分土壤总孔隙度平均大小依次为毛竹林针阔混交林阔叶混交林杉木林荔枝林;(4)5种林分土壤贮水量大小为毛竹林针阔混交林荔枝林杉木林阔叶混交林。总体而言,荔枝林枯落物持水性最好,毛竹林土壤持水性最强。     

广西猫儿山森林群落土壤物理性质空间变异及其环境影响因素

探索土壤物理性质沿环境梯度的变异规律及其影响因素,对森林群落物种分布格局和森林水文研究具有重要意义。以猫儿山不同海拔典型森林群落为研究对象,采用野外调查、实验分析与冗余分析(RDA)相结合的方法,研究了猫儿山海拔梯度上常绿阔叶林、常绿落叶阔叶混交林、常绿针阔叶混交林和山顶矮林等典型森林土壤物理性质的空间变异及其对环境因子的响应。结果表明:0~60 cm层土壤容重随海拔的增加而降低,土壤总孔隙度、非毛管孔隙度、毛管孔隙度、土壤含水量、最大持水量和毛管持水量随海拔的增加而增加,局部有所波动。除常绿阔叶人工林和常绿针阔叶混交林外,其他森林土壤容重均随土壤深度的增加而增大,土壤总孔隙度和毛管孔隙度随土壤深度的变化趋势则表现各异。土壤容重、毛管孔隙度和总孔隙度在0~10 cm层变化最为剧烈。土壤含水量、土壤最大持水量和毛管持水量的垂直变化规律均随土壤深度的增加而减少。RDA结果显示,海拔和植被类型是影响猫儿山土壤物理性质的主要因素,共解释了土壤物理性质变异的46.1%。海拔通过水热状况影响植被类型及其分布,进而影响林下土壤物理性质。     

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.