本文详细阐述了荒山和荒地造林的技术关键点，包括：正确选择树种、把握好造林的密度和配置、掌握好造林时间同造林方法等等方面，以及分析研究了造林后具体的抚育管理措施。

提问得当,可以有效激发学生思考的积极性,活跃课堂气氛,提高教学效果.而提问不当,往往会启而不发,变成教师毫无价值的自问自答,或者表面上轰轰烈烈,实际上空洞无物,毫无意义.因此,教师在教学中,必须注重在提问的艺术上下功夫,做一名巧问的智者.

Enriched nutrient patches within natural soil represent an important source of nutrients for tree growth. In the present study, pot experiments in a heterogeneous nutrient environment were conducted to investigate the influence of light conditions and interspecific competition on the root foraging traits and seedling growth of Pinus massoniana and Schima superba. The root foraging scale and the whole-seedling biomass of both species were decreased by shading. The result of this treatment was a lower sensitivity to nutrient heterogeneity in plants that underwent the shading treatment than in plants that were exposed to full-light conditions. The above-ground biomass and whole-seedling biomass of S. superba were not affected by competition with P. massoniana. In contrast, the above-ground biomass and whole-seedling biomass of P. massoniana were negatively affected by competition with S. superba. The more rapid rate of root extension and the more efficient resource uptake of S. superba appear to explain this effect. The species-specific patterns of the influence of environmental factors on foraging ability and seedling growth should be given thorough consideration and should be applied to afforestation and to the management of tree plantations.

Six natural stands of Schima superba with latitude and elevation gradient were selected in Zhejiang and Fujian Provinces to study individual phenotypic variation in stem form,bark morphology and wood properties,as well as effect of latitude and elevation on these traits.The purpose of our experiment was to provide a theoretical basis for the further exploitation and utilization of within-species variation of S.superba.The results revealed various types of bark traits and wood color among natural stands of S.superba.There were significant differences in stem form,bark type and wood basic density,but not in wood texture distortion degree among different stands.In contrast,the largest within-stand variation in wood texture distortion degree and the lesser within-stand variation in stem fullness,stem straightness and wood basic density were observed.Radial analysis in wood property showed that wood basic density decreased from pith to bark gradually.The ring width was increased at first but followed by reduction,and remain constant during 15th to 25th rings.Results also demonstrated that natural stands from higher latitudes exhibited higher stem fullness and straightness,thinner bark and lighter wood color relatively,whereas no clear regularity were observed for other characters.The effect of elevation was more significant in comparison with latitude,as increased trunk fullness,thinner and smoother bark,as well as decreased trunk straightness,ring width and wood basic density were observed in natural stands from higher elevation.The individual correlation analysis based on two natural stands from different elevation in the central production region showed that the correlation among traits were quite different and depending on different elevation of stands.In high elevation stands,bark traits could be used as good morphological indicators for wood properties and diameter growth.Individuals with higher stem fullness usually exhibited less wood basic density,as well as bark with lighter color and smooth surface.At the same time,individuals with higher stem straightness and dark bark usually exhibited faster grew speed in diameter.For stands from low elevation,bark thickness was demonstrated to be a good indication on wood basic density and other traits,as decreased wood texture distortion degree and increased wood basic density were observed in individuals with higher stem straightness,lighter bark color and large DBH increment.

Several Schima superba pure stands and S. superba-Chinese Fir mixed stands afforested during 1968—1997 were selected to study the effect of slope position, slope direction and mix planting with Chinese Fir on growth and wood basic density of S. superba plantation in Jianou, Fujian Province. The results revealed a significant effect of slope position and slope direction on the growth and stem form of S. superba, but lower effect on wood basic density. The increment of crown and height was enhanced, and stem form was improved at sunny slope and down-slope, compared with shady slope and mid-slope, whereas DBH increment was higher in shady slope with higher soil water content. When S. superba were mixed with Chinese Fir at appropriate ratio(such as the ratio of 1∶3), stem form and the growth of DBH, height and crown all were improved significantly. The probability of stem forking(SF) of S. superba was fluctuating within 22.50%-35.75%, which mainly was single fork lower than 0.5 m. In pure stands on sunny slope or down-slope and mixed stands(ratio of 1∶3), the probability of stem forking was lower. Moreover, slope position had larger influence on stem fork formation than slope direction. The wood basic density was gradually decreased from pith to bark, was decreased sharply from 15th to 20th rings, and reached the minimum during 35th to 40th rings. The reduction velocity of wood basic density from pith to bark was increased with the increasing of the diameter increment. The ring width was increased at first and followed by a reduction, with the largest wood formation speed during 5th to 15th rings. Accordingly, it was proposed that S. superba plantations should be build on sunny slope and down-slope which had better condition of water, fertility and light. Based on the result, mixed planting at appropriate ratio,enhancing removing buds and shoots of young stand as well as tending and thinning of middle-age stand was proposed to control the stem fork formation, improve the diameter growth and promote plantation productivity in medium-later period and radial homogeneity, and finally obtain the cultivation objective on fast-growing and high-quality craft timber stands.

Aims Our aim was to investigate the genotypic variations among semi-sib families of Pinus massoniana for adaptive changes in root morphology and architecture in response to different types of low soil phosphorus(P) availability and their relationships to plant growth and P efficiency.Methods Pot experiments were conducted during the 2010 growing season in a nursery located in Chun’an County of Zhejiang Province,China.Seven semi-sib families of P.massoniana contrasting in root architecture and P efficiency were compared for their root morphological and architectural traits and their relationships to plant growth and P efficiency under both heterogeneous and homogeneous low P conditions.Important findings Large genotypic variations were observed under different types of low-P conditions.The adaptive mechanism for P deficiency was different under heterogeneous and homogeneous low-P conditions.Under homogeneous low-P conditions,adaptive responses of root growth parameters were present in genotypes with high-P efficiency such as ‘3201’ and ‘1217’,while it was not observed in genotypes with low-P efficiency.Root architecture was not closely related to plant P efficiency under homogeneous low-P conditions.Under heterogeneous low-P conditions,root architecture was found to closely related to P efficiency.Genotypes with shallow root architecture had optimal root parameters including root length,surface area and biomass in the top layer of soil,thus having the greater ability for P absorption and having higher P efficiency and biomass.The heritability for the root biomass and the proportion of root in the top soil layer was 0.88 and 0.72,respectively.A significant interactive effect between patterns of low-P conditions and P efficiency was observed.Given that P.massoniana has great genetic potential for adaptation to low-P soils,the selection of high-P efficiency genotypes with optimal root architecture may significantly increase wood production of P.massoniana under low-P conditions.

An experiment with factorial design was conducted to investigate the effects of substrate composition,slow release fertilizers,and container size on seedling growth and quality of Schima superba.The seedling height and ground diameter were promoted by high peat percent in substrate,whereas the root:shoot ratio(RSR) was reduced.The application of 2.5 kg·m-3 slow release fertilizers had little effect on the above-ground part of plants and the RSR.In contrast,the root growth was inhibited with the increased amount of slow release fertilizers.The plant height and ground diameter were promoted and the RSR decreased by larger container size.Based on the seedlings quality and cost,the optimal regime may be substrate composition with peat∶bran=7∶3,2.5 kg·m-3 of slow release fertilizers,combined with container of 5.5 cm×10 cm dimensions.The statistical analysis revealed that quality of container seedlings was affected by substrate composition,slow release fertilizers,as well as container size.The interactions were also found among the three main effects,thus it is possible to properly adjust the application of slow release fertilizers and container size according to the substrate composition so as to produce low cost and high quality container seedlings.

通过对刺槐的育苗实验总结出来一套适用于山区培育刺槐的有效方法。采用这种技术,成本低,操作简单,成苗率高、可用性强,具有一定的推广价值。

A pot experiment consisting of three different heterogenerous nutrient environments was designed,with homogeneous nutrient environment as control,to study the differences of foraging behavior of Pinus massoniana to N and P nutrient patches.The results showed that P.massoniana exhibited greater seedling growth,more biomass accumulation in P and whole nutrient heterogeneous environment,while it responsed unsensitively to nutrient heterogeneous environment.The root physiological and morphological plasticity played important roles when P.massoniana absorbed nutrient in P patch with poor mobility.Moreover,in P patch,root growth exhibited some characteristics,such as root proliferation,greater root scale,higher precision and sensitivity,improvement of root N and P absorption efficiency.However,its root scale,precision and sensitivity were lower in N patch,while root did not need to proliferate to acquire N with rich mobility,and N and P absorption efficiency were also low,which could illuminate that root physiological and morphological plasticity had no obvious effects on acquiring nutrients in N-enriched patch.The foraging behavior of P.massoniana in whole nutrient patch was similar with in P heterogeneous nutrient environment.

Considering the ubiquitous heterogeneity in spatial distribution of soil nutrients, we conducted a pot experiment to investigate the foraging traits and growth performance of four important subtropical tree species in a heterogeneous nutrient environment. The tested species exhibited large differences in foraging traits as well as growth benefits obtained from root foraging. Pinus massoniana , Schima superba and Liriodendron chinese all showed a higher degree of root morphological plasticity (expressed as relative fine root mass difference; RFRMD) than Cunninghami lanceolata ( P < 0.05). P. massoniana exhibited the largest degree of morphological plasticity, followed by L. chinese and S. superba , whereas there were no significant differences in RFRMD among the three species. S. superba was the only species that exhibiting both morphological plasticity and physiological plasticity. Both P. massoniana and S. superba exhibited greater whole-seedling biomass and high sensitivity in response to nutrient heterogeneity, resulting from both types of plasticity. In contrast, both types of root plasticity were poor for C. lanceolata , resulting in poor growth benefit in heterogeneous environments. As for L. chinese , the root proliferation in nutrient-rich patches occurred at the expense of depressed root growth in other parts of the root system, leading to the lack of increment in total root biomass and nutrient absorption in heterogeneous environments. Our results provide insight and practical advice for silviculture and forest management.

Experiment was conducted on effect of different ratio of substrate composition,slow-release fertilizer quantity on container seedling growth and survival rate of bud seedling transplantation of Schima superba.The result showed that substrate composition of peat/chaff with 7:3 could promote seedling height and ground diameter growth as well as transplantation survival rate.Application of 1.5 kg/m3 or 2.0 kg/m3 slow-release fertilizer in the substrate had better growth of seedling.The experiment concluded that the best condition for container seedling growth was: substrate composition of peat/chaff with 7:3,applied with 1.5 kg/m3 slow release fertilizers.

为了研究邻株竞争对马尾松(Pinus massoniana)和木荷(Schima superba)觅取异质分布养分机理和行为的影响,我们设计单植、双株纯栽和两株混植3种栽植方式,构建了同质和异质养分环境开展盆栽实验.结果表明:单植时,马尾松和木荷苗木生长对斑块养分反应敏感,与同质养分环境相比,两树种在异质养分环境中具有苗高生长量大、干物质积累量高、根系在富养斑块中大量增生,根系N、P含量和吸收效率高等特点.在异质养分环境中,木荷与马尾松邻株竞争时的生长表现优于双株纯栽模式而与单植处理相近,根系形态可塑性和生理可塑性在其觅取斑块养分中的作用显著增强:与木荷邻株竞争时,马尾松苗高生长也表现出较单植和双株纯栽模式一定的优势,这与其根系的广布性、觅养精确性和反应敏感度变化较小及富养斑块中根系P素含量和吸收效率较高等有关.相反,同种邻株竞争则使得异质养分环境中马尾松和木荷的根系广布性减小,反应敏感度减弱,富养斑块中根系N、P含量降低,苗高生长量和干物质积累量减小.与马尾松相比,同种邻株竞争对异质养分环境中木荷生长的负向影响更为强烈.建议在生产中采用混交造林的方式促进马尾松和木荷生长.若要营造人工纯林,可通过适当降低初植密度或及时调控林分密度促进林木生长.

With the rapid development of highly centralized city,urban landscape takes a new look and feature and urban streets are the city's framework,linking the various functional areas of the city.Green plantation design for urban street is the heart of the city streets.This paper analyzed the status and problems of streetscape in the northern cities.A few principles and suggestions were proposed for the decision maker in the landscape green.

Aims Chinese fir(Cunninghamia lanceolata),an important tree of timber plantations in South China,is a fast-growing coniferous species with high yield and quality of wood.Since the forest soil in South China is highly heterogeneous in nutrients,our objective is to study responses of Chinese fir to soil heterogeneity.Methods We used pot experiments under heterogeous and homogeneous environments to study tree growth,dry matter accumulation and allocation,root morphology and nutrient absorption efficiency of three open-pollinated varieties of C.lanceolata(`Long 15',`Jinping 45' and `Jing 398') to detect the differences in their adaptability to the heterogenous nutrient environment.Important findings The three varieties were significantly different in their adaptability to the heterogenous nutrient environment and in their response to soil patches.`Jinpin 45' exhibited higher plant height,higher biomass accumulation and more developed roots in the heterogeneous environment than homogeneous environment,but `Long 15' and `Jing 398' grew better in the homogeneous environment.Although the responses of the three varieties were different,roots proliferated mainly in poor patches.`Jinping 45' showed high root physiological plasticity in the heterogeneous environment,but `Long 15' and `Jing 398' were low and average,respectively,in the hererogeous environment.The root concentration of N,P and K in the heterogeous environment(poor-patch) was lower than in the homogeneous environment(rich-patch);this is different from Pinus massoniana,which had high nutrient absorption.However,concentration of nutrients was not lower in rich-patch than poor-patch.Further more,it can be inferred that `Jinping 45' grew better in the heterogeneous environment than the homogeneous environment not only because of physiological plasticity but also because of a larger portion of biomass and nutrients distributed to leaves.

A factorial combination pot experiment was designed to study the growth response and foraging behavior of three South China forestation species Pinus massoniana, Schima superba and Liriodendron chinense under heterogenous nutrient envionment and different light conditions. The results demonstrated that under full light, the plant height and biomass of P. massoniana and S. superba were enhanced in heterogenous nutrient environment, with the root biomass increased by 99.5% and 66.7%, respectively, compared with that in homogenous environment; while L. chinense exhibited singnificant growth benefits in homogenous environment. The root scale, foraging precision, and nutrient uptake of S. superba reduced markedly under shading, which in turn decreased the growth benefits in heterogenous nutrient environment. The influence of shading was weaker on P. massoniana than on S. superba, still with some growth benefits for P. massoniana due to its root proliferation and enhanced nutrient uptake in nutrient rich patch. There was a slight influence of shading on the foraging precision and sensitivity of L. chinense root, with no growth response pattern change to heterogenous nutient environment occurred. It was concluded that three tree species not only differed in the inheritance of root foraging mechanism and behavior, but also varied in the response pattern to light condition. Therefore, different measures should be adopted in forestation with the three tree species to enhance the forest productivity.

In order to study the ethanol properties of ZnO nanowires,the gas sensor was fabricated with ZnO nanowires synthesized by thermal evaporation of Zn powders with a purity of 99.9%.With methyl cellulose as binding admixture,the heater-typed gas sensor was prepared at different sintering temperatures.The morphology of the product was determinated by SEM.The gas sensitivity of ethanol's vapor was tested.The results reveal that the combination of ZnO nanowires rapidly decreases the ratio of the surface area to the volume with the increase of the sintering temperatures,affecting the senstivity of the gas sensor.When the sintering temperature reaches 500℃,the sensitivity of the gas sensor be comes the highest.

The guardian to come to the child always not satisfactory worried feeling from always to re- quest the child to the guardian to adapt on own initiative oneself.The guardian must remove the worried feeling,obtains child's body and mind joyfully with the study,the life together progresses,must get off the high horse,adapts child's body and mind growth rule on own initiative,progresses together with the child.

Large scale ZnO nanowries and nanorods have been successfully produced by physical thermally evaporating ZnS powders.The morphology,inside structure and optical properties of ZnO nanowires have been studied by scanning electric microscope,transmission electron microscopy,laser raman spectroscopy and fluorescence spectroscopy.The results show that ZnO nanowire obtained has the hexagonal and single crystal structure.Further more,the ZnO nanowires have preferable light properties and good crystalline.The length of ZnO nanowires is in the range of 2～5μm,with diameter about 60nm.The growth of ZnO nanowires is controlled by VS mechanism.

ZnO nanowires with V tips have been prepared using thermal evaporation by controlling the carrier flow and O2 flow.The room-temperature photoluminescence(PL) and Raman scattering of ZnO nanowires have been investigated.Different from other morphology of ZnO nanowires' PL spectra,broad and intense blue emission from 423 nm to 458 nm and weak green emission at 527 nm were observed for the V tip ZnO nanowires.However,no ultraviolet emission was observed.Compared with the Raman spectra of the ZnO powder,3 cm-1 red shift was observed for ZnO nanowires,which should be attributed to the phonon confinement.