海涂桔园防护林营建技术探讨

我县海涂资源丰富,并已连片集中种植柑桔4.1万亩,1985年产桔19.53万担,占全县柑桔产量的81％。海涂柑桔易受风、冻、旱、碱等灾害而影响生长和产量。1980年开始,我县配合发展海涂柑桔生产,有规划、有计划、有步骤地营建海涂桔园防护林,六年来共植树218万株。实践证明,沿海防护林对海涂柑桔起到积极作用,尤以防风、防冻效应最明显。同时在经受了灾害考验后,也暴露了桔园防护林建设中的一些问题。本文试从几年来实践中出现的问题,就改进海涂桔园防护林营建技术作一探讨。     

桔园间作藿香蓟抑制吸果夜蛾为害

1990年从外地引进绿肥藿香蓟种子播于庆元县山地桔园,当年发现凡间种绿肥的桔树被吸果夜蛾为害造成的落果减少。为了进一步证实其作用,1991年进行了对比调查。根据8月24日～10月9日两个果园6次调查的结果,桔树四周间种藿香蓟的桔园虫果脱落率仅为0.15％;少量间种的桔园虫果脱落率为4.7％;未间种的桔园的虫果脱落率达7.3％,效果明显。其中,早熟温州蜜柑园间种藿香蓟对吸果     

草甘膦防除丝茅草效果好

1986年5月,江永县桃川镇周堂柑桔园和县原种场应用10％草甘膦(广西南宁市化工实验场出产)防除初结果桔园丝茅草,面积100亩。每亩施药量1—1.5公斤,稀释50—80倍液,再加50—60克洗衣粉,以增加粘附力。于晴天露水干后进行喷雾,使     

桔园防护林网的效应研究

寒风危害是我国柑桔北缘地区威胁柑桔生产的一大问题。调查研究和生产实践证明,寒风使叶片失水卷曲、脱落,加剧柑桔树体的冻害,削弱树势,甚至引起树脂病的大发生。我们通过人工模拟试验证明,在-7℃低温下,加上8米/秒的大风,则柑桔冻害程度相当于-9℃低温造成的危害。据报道,苏联1.86万公顷有防护林保护的柑桔,亩产较没有防护林的高20%。日本也有类似报道。我们于1980—1982年在我场不同树龄的温州蜜柑园,利用现有的防护林带,进行了桔园防护林效应的研究。现简报如下。     

2004年万安县柑桔红蜘蛛重发生的原因及防治

2004年万安县柑桔园红蜘蛛发生特别严重，虫口从3月中旬开始上升，3月底出现第一个为害高峰。4—6月持续高发，用药量剧增，防治间隔期由往年的45天一次变为15天一次，80％的桔园虫口密度大增，部分桔园出现90％的树体叶片整体发白现象。     

上海郊区柑桔园应注意炭疽病的防治

上海郊区柑桔园应注意炭疽病的防治柑桔是上海郊区的主要栽培果树。１９９３年冬末至１９９４年初春，位于上海市东南的南汇县泥城乡兴隆村一处桔园发生严重落叶。该桔园为温柑尾张、兴津等品系，９年生。经观察，一般落叶率约３０％，严重树达６０％—７０％，落叶部位主...     

低丘红壤防护林对柑桔品质的影响

低丘红壤防护林对柑桔品质的影响陈喜靖，罗永进，汪永祚，叶增饭，柴锡周，钟哲科（浙江农科院土肥所杭州３１００２９）（金华县黄土丘陵开发办）（浙江省林科所）桔园防护林在柑桔防冻、促进营养生长及提高产量方面都有明显的作用，这已经为许多研究结果所证明．但是，...     

幼龄椪柑园绿肥套种调查

近年来,常山县辉埠镇大部分桔园套种豆类作物的面积明显增加。据初步调查全镇3635亩桔园有80％以上都套种绿肥,其中360亩胡柚基地95％以上播种了印尼绿豆、花生、佛豆等。 为了了解桔园套种绿肥对树势的生长效果及产量的影响,笔者于1990年12月对该镇大埂村许土生户的椪柑园连续套种印尼绿豆进行了调查。 该椪柑园为1986年定植,面积15亩。其     

枯园套种竹荪栽培技术

在桔园中以竹屑为原料套种竹荪，省去遮阴棚．降低竹荪种植成本，并充分利用土地资源和毛竹资源，提高土地和毛竹的利用率，减少竹屑的环境污染，为实施桔园立体开发、增加农民收入提供了一条有效途径。我们通过几年的实践，探索出了一套桔园套种竹荪高产栽培技术，仅供参考：     

利用柑桔和香蕉混植生态控制吸果夜蛾为害初探

通过1984—1986年对桔园内外种植香蕉与不种植香蕉的不同情况进行观察的结果,发现香蕉花对吸果夜蛾有很强的引诱力,桔蕉混植显著减少了吸果夜蛾对柑桔果实的为害。桔蕉混植还使青蛙得以繁衍,对控制桔园害虫有利。     

提高我国柑桔果实品质的探讨

柑桔(Citrus Linn)是一种热带和亚热带植物,它是我国南方重要的经济作物。柑桔的产量和品质与多种因子相联系。这些因子是:生产对象、环境因子和人为因子。本文讨论了柑桔品质与上述因子之间的相互关系,以及提高我国柑桔果实品质的方法。为了提高我国柑桔果实的品质,作者建议:(1)选择生态环境适宜的地区栽培柑桔;(2)选育和推广柑桔良种;(3)采取各种有效措施改造桔园生态环境,诸如搞好桔园基本建设,营造桔园防护林和应用合理的栽培技术等。     

Twelve-year change in tree diversity and spatial segregation in the Mediterranean city of Santiago,Chile

Tree diversity is one of the most important components of urban ecosystems, because it provides multiple ecological benefits and contributes to human well-being. However, the distribution of urban trees may be spatially segregated and change over time. To provide insights for a better distribution of tree diversity in a socially segregated city, we evaluated spatial segregation in the abundance and diversity of trees by socioeconomic group and their change over a 12-year period in Santiago, Chile. Two hundred vegetation plots were sampled across Santiago in 2002 and 2014. We found that overall abundance and diversity of urban trees for the entire city were stable over 12 years, whereas species richness and abundance of native tree species increased. There was segregation in tree species richness and abundance by socioeconomic group, with wealthier areas having more species and greater abundance of trees (for all tree species and native species) than poorer ones. Tree community composition and structure varied with socioeconomic group, but we found no evidence of increased homogenization of the urban forest in that 12 years. Our findings revealed that although tree diversity and abundance for the entire city did not change in our 12-year period, there were important inequities in abundance and diversity of urban trees by socioeconomic group. Given that 43% of homes in Santiago are in the lower socioeconomic areas, our study highlights the importance of targeting tree planting, maintenance and educational programs in these areas to reduce inequalities in the distribution of trees.     

Physical influences of landscape on a large-extent ecological disturbance: the northeastern North American ice storm of 1998

The 1998 ice storm was a large-extent ecological disturbance that severely affected the eastern Adirondack forests of northern New York. Ice damage produced widespread breakage of limbs and trunks in susceptible trees. Although ice storms are common within northeastern North American forests, the magnitude and extent of the 1998 storm far exceeded damage caused by typical ice storms in the recent past. While plot and stand-scale ecological impacts of ice storms have received attention insofar as tree species vulnerability, stand age susceptibility, and microhabitat alterations, larger-extent damage patterns have not been previously evaluated. The normalized difference vegetation index (NDVI) was employed to assess forest vigor and canopy density in atmospherically corrected Landsat Thematic Mapper (TM) satellite imagery of the Adirondacks. Digital change analysis of the baseline forest condition (1990 NDVI data), and the condition encountered in a post-storm image (1998 NDVI data) was conducted. Forest damage was separated from natural variations in canopy reflectance by employing a generalized linear model that incorporated in situ measurements. A robust empirical variogram analysis revealed that locations of tree damage were significantly correlated for distances up to 300 meters. Intensely-damaged forest exhibited greater spatial dependence, but over a smaller distance. Canopy damage was not greater proximate to stream and forest boundaries, and did not follow our hypothesis of decreasing damage with distance from the boundary. Overall, we show that local topography (elevation and aspect), forest composition (deciduous or coniferous), and the meteorological characteristics of the disturbance event acted together to determine the spatial extent of ice storm damage.This revised version was published online in May 2005 with corrections to the Cover Date.     

Contrasting natural regeneration and tree planting in fourteen North American cities

Field data from randomly located plots in 12 cities in the United States and Canada were used to estimate the proportion of the existing tree population that was planted or occurred via natural regeneration. In addition, two cities (Baltimore and Syracuse) were recently re-sampled to estimate the proportion of newly established trees that were planted. Results for the existing tree populations reveal that, on average, about 1 in 3 trees are planted in cities. Land uses and tree species with the highest proportion of trees planted were residential (74.8 percent of trees planted) and commercial/industrial (61.2 percent) lands, and Gleditsia triacanthos (95.1 percent) and Pinus nigra (91.8 percent). The percentage of the tree population planted is greater in cities developed in grassland areas as compared to cities developed in forests and tends to increase with increased population density and percent impervious cover in cities. New tree influx rates ranged from 4.0 trees/ha/yr in Baltimore to 8.6 trees/ha/yr in Syracuse. About 1 in 20 trees (Baltimore) and 1 in 12 trees (Syracuse) were planted in newly established tree populations. In Syracuse, the recent tree influx has been dominated by Rhamnus cathartica, an exotic invasive species. Without tree planting and management, the urban forest composition in some cities will likely shift to more pioneer or invasive tree species in the near term. As these species typically are smaller and have shorter life-spans, the ability of city systems to sustain more large, long-lived tree species may require human intervention through tree planting and maintenance. Data on tree regeneration and planting proportions and rates can be used to help determine tree planting rates necessary to attain desired tree cover and species composition goals.     

Progress in research on meteorological disaster indicators of major fruit trees in China北大核心CSCD

China is an important fruit-producing country in the world. In recent years, the fruit planting area in China increased significantly, and the total fruit output has also rapidly increased. In this context of development, the characteristic fruit industry has become an important source of rural agricultural economic income in China. The stable production of characteristic fruits and disaster prevention and mitigation are of great significance for improving people's living standards and promoting the development of agricultural economy. At the same time, China has a vast territory, spanning three main climatic zones from north to south, and the damage caused by meteorological disasters of fruit trees is extremely serious and frequent. Therefore, research on meteorological disasters of fruit trees is one of the hot topics in agrometeorological disasters research. Especially, the research on meteorological disaster indicator of economic fruit trees is particularly important, which is an inevitable link in disaster monitoring, early warning, defense, planting planning, risk zoning and other research. In this paper, the main meteorological disaster indicators of fruit trees in China are classified and systematically expounded, by using the method of classification and summary. In this paper, the basic concept and significance of meteorological disaster indicators of fruit trees are defined firstly, and then the research history and progress of meteorological disaster indicators of fruit trees in China are summarized. The main research methods of meteorological disaster indicator of fruit trees in China, including fruit trees and disaster types, technology level and main achievements, were summarized in two periods before and after the 21st century. On this basis, the existing meteorological disaster indicators of fruit trees in China are divided into three categories according to their construction methods: the empirical indicator construction method based on disaster verification and disaster investigation; the comprehensive indicator construction method based on the relationship between disaster-causing factors and yields; and the experimental construction method based on artificial climate chamber or artificial climate box. According to the composition types of meteorological disasters of fruit trees in China, the existing meteorological disasters indicators of fruit trees are divided into three categories: single factor indicators, multi-factor indicators and comprehensive indicators. According to the key meteorological factors causing meteorological disasters of fruit trees, the existing meteorological disasters indicators of fruit trees are divided into several categories: low temperature disaster indicators, high temperature disaster indicators, drought disaster indicators, rainstorm disaster indicators and so on. Secondly, aiming at the northern fruit trees, this paper summarizes the research on late frost damage indicator of apple, pear, apricot, plum and grape in spring, drought disaster indicators of apple and walnut, hot damage indicators of apple and kiwifruit in summer, rainstorm disaster indicator of apple and jujube in autumn, and freezing injury indicators of pear, apricot and jujube in winter. For southern fruit trees, it summarizes the research on high temperature damage indicator of citrus, and the research on freezing damage indicator of citrus, litchi, longan, mango and loquat in winter. At the same time, this paper summarizes the types, construction methods, uses, advantages and disadvantages of the above meteorological disaster indicators of fruit trees in agrometeorological service. Finally, this paper discusses the existing problems and the future development direction of the research on meteorological disaster indicators of fruit trees, from the aspects of indicator composition, indicator construction method, fruit tree species, industrial development needs, and new technology and methods. It is expected that the results of this study can provide reference for the distribution of main fruit trees, industrial optimization, disaster prevention and mitigation, and provide scientific guarantee for the healthy, stable and sustainable development of fruit tree growing industry in China. © 2019 Journal of Fruit Science     

Tree and impervious cover change in U.S. cities

Paired aerial photographs were interpreted to assess recent changes in tree, impervious and other cover types in 20 U.S. cities as well as urban land within the conterminous United States. National results indicate that tree cover in urban areas of the United States is on the decline at a rate of about 7900 ha/yr or 4.0 million trees per year. Tree cover in 17 of the 20 analyzed cities had statistically significant declines in tree cover, while 16 cities had statistically significant increases in impervious cover. Only one city (Syracuse, NY) had a statistically significant increase in tree cover. City tree cover was reduced, on average, by about 0.27 percent/yr, while impervious surfaces increased at an average rate of about 0.31 percent/yr. As tree cover provides a simple means to assess the magnitude of the overall urban forest resource, monitoring of tree cover changes is important to understand how tree cover and various environmental benefits derived from the trees may be changing. Photo-interpretation of digital aerial images can provide a simple and timely means to assess urban tree cover change to help cities monitor progress in sustaining desired urban tree cover levels.     

Factors influencing long-term street tree survival in Milwaukee,WI, USA

Street trees are exposed to a variety of site conditions, environmental factors, and physical disturbances which influence their survival in urban areas. This study draws on 25 years of urban forest monitoring data from the city of Milwaukee, WI (United States) to model the impacts of these factors on tree survival for a single cohort of trees. Tree condition, tree size, tree species, and site attributes were measured initially in 1979. These factors were measured again in 1989 and 2005 and compared to construction data for the same area during the study period. Multivariate logistic regression was used to identify factors associated with tree survival. Cross-validation show the final model could successfully predict tree survival nearly 85% of the time. Results indicate that tree survival varied by species. Additionally, trees were more likely to die as trunk diameter increased, planting space width decreased in the tree lawn, and tree condition decreased. Finally, trees adjacent to construction were nearly twice as likely to die as those not exposed to development and redevelopment activities.     

The Effect of Distance from Pollinizer Varieties on the Fruit Set on Trees in Plum and Apple Orchards

The fruit set on plum trees decreased greatly with increase in distance from pollinizer trees, and less so with increase in distance from honey-bee colonies. Trees adjacent to pollinizers had a greater set on the sides facing the pollinizers than on their far sides. Parts of trees touching “ bouquets ” had a greater set than parts without bouquets.

In an apple orchard with main variety and pollinizer trees in separate blocks, the fruit set was greater on the main variety trees adjacent to the pollinizers than on trees farther away. In an apple orchard with a pollinizer tree as every third tree in every third row, main variety trees had a greater fruit set, more seeds per fruit, and more carpels with seeds per fruit, on the sides near to their adjacent pollinizers than on their far sides. The fruit set, number of seeds per fruit, and number of carpels with seed per fruit, were greater the nearer the trees were to the adjacent pollinizer.

These results are discussed in relation to the foraging behaviour of honey-bees and to methods of arranging pollinizer and main variety trees in orchards.     

Changes over time in tree cavity availability across urban habitats

In urban ecosystems, tree cavities provide critical habitat for a variety of wildlife, and their occurrence is influenced by tree health, management, and cavity excavators. Changes over time in vegetative structure, human use patterns, and built environment affect the formation and persistence of tree cavities, and these changes may differ in various urban habitats. Trees with some decay are often associated with tree cavities, however, parks and residential habitats which are highly managed often lack highly-decayed trees, and large trees which are dead and damaged are likely to be removed and replaced with saplings. We surveyed changes over seven years (in 2013 and 2020) in the abundance of both excavated woodpecker cavities and decay cavities, in three urban habitats (forest, park, and residential) in the Chicago region, IL, USA. We observed greater stability of cavity abundance in managed park and residential habitats over time. Low numbers of highly-decayed trees in park and residential habitats were associated with reduced excavated cavity presence compared to forests. As expected, in both 2013 and 2020, the probability of cavity presence for both excavated and decay cavities was increased with greater tree size and higher levels of tree decay, though the patterns of this association varied between habitat types and years. The continued replacement and maintenance of existing trees means that managed park and residential habitats were more stable than unmanaged forest remnants, which are vulnerable to large changes in tree characteristics which could foster unpredictable booms or busts in cavity supply. A stable inventory of tree-cavities depends on preserving large trees, and decay of urban trees benefits habitat quality for cavity-nesters. Pruning of branches or removal of dead trees curtails the life-cycle of tree cavities in decayed branches, so that more highly managed habitats contain fewer cavities than the number of trees could potentially support. Cavity abundance could be improved in stable habitats through reduced intervention where safe, allowing cavity development to occur in situ.     

三峡库区柑橘种植规模与果园管理的关系分析

利用对库区1982年分户经营前后的30个柑橘园经营管理状况的追踪调查资料,根据经济学一般原理进行种植规模与果园管理的关系分析。在实行土地承包制的过程中,柑橘园不是按照一个整体承包给一个或几个农户进行专业化管理,而是将柑橘园作为一种集体福利“分树到户”。随着柑橘园的经营规模由大变小,当低于“最小必要规模”时,经营状况将发生质的变化。而“最小必要规模”是动态变化的,在1985年前后,户均333.3m2左右的柑橘园可以勉强维持,1987年上升到户均466.7m2以上,1994年上升到666.7m2以上,而户均1000m2以上的柑橘园可以维持到现在。调查、分析表明,种植规模是影响柑橘生产的最关键的因素,目前在三峡库区,1086.7m2以上的果园才能维持正常的生产经营活动。