道路绿化树木修剪及剩余物制片联合机的研究与分析

通过对国内外树木修剪机械及修剪后的剩余物处理现状研究,提出一种道路绿化树木修剪及剩余物制片联合机,并对其经济效益进行了分析。该机实现了路旁树木的修剪及剩余物现场处理。     

国内外树木移植机械的研究现状与发展趋势

随着我国城市空气污染的加剧,增加城市绿化树的拥有量将有助于改善城市生态环境,提高人民的生活质量。目前城市绿化工作多采用人工移植树木的方式,其劳动强度大、效率低、成活率也不高。同时随着劳动力的短缺问题的日益突出,机械化城市绿化将成为今后的发展趋势。为此,介绍了国内外树木移植机械的研究现状,分析了树木移植机的发展趋势,并为我国树木移植机的发展研究提出了建议。     

系统抽样调查在森林蓄积量测定中的应用

以江苏省农博园湿地松生态林区典型地段为调查研究对象,应用系统抽样的方法进行布点,样地测设及调查.运用CAD绘图软件对调查总体求算面积,运用一元材积表对调查结果进行汇总,并探讨了不同形状样地调查数据的抽样估计精度.结果表明：利用CAD绘图软件绘图并求算面积的方法较传统手工绘图的方法简便,准确.不同形状样地的调查数据的估计精度非常接近,考虑到方形样地测设较简单,因此,建议在森林的系统抽样调查中选用方形样地.     

牡丹组织培养技术研究综述

从外植体类型、培养条件、培养基种类、生根培养方法、组培苗移栽驯化几方面综述了牡丹组织培养技术的研究现状,分析了目前牡丹组织培养中存在的问题,提出了今后的发展方向。     

瑞丽柠檬园红蜘蛛消长规律及药剂防治研究

在云南省瑞丽市进行了柠檬园红蜘蛛的消长规律及药剂防治研究。结果表明:柠檬红蜘蛛主要在11月至次年1月发生,其发生量在1月中旬达到高峰(2500~3000头/株);红蜘蛛在树冠北方、南方的发生量较多;柠檬园红蜘蛛的发生和为害与温度、湿度、食料、施肥、施药等因素关系密切;在7种供试药剂中,以4%螺螨酯悬浮剂、1.8%阿维菌素乳油和73%炔螨特乳油对红蜘蛛的防治效果较好,且对柠檬的嫩梢、花和幼果安全无害。     

Range fidelity: The missing link between caribou decline and habitat alteration?

Conservation of forest-dwelling caribou (Rangifer tarandus caribou) is of great concern across most of its range. Anthropogenic disturbances, primarily logging activities, have been identified as the most important cause of caribou decline, although the mechanisms underlying this decline are not fully understood. Caribou commonly display fidelity to calving sites or seasonal ranges, but the potential role of this life-history trait has been largely overlooked in research and conservation planning. This is surprising because sites and ranges with high inter-annual use should have high conservation value. We investigated the relationship between habitat disturbances and home-range fidelity of forest-dwelling caribou across three study sites in Québec, Canada, using a broad range of natural and anthropogenic disturbances. Between 2004 and 2007, we tracked 47 adult female caribou using GPS collars. Home-range fidelity varied between seasons, being higher during calving and summer, and lower during winter. Caribou reduced fidelity following natural and anthropogenic disturbances, the latter having a stronger negative influence. Anthropogenic disturbances had a strong negative impact on home-range fidelity during annual, summer and winter periods, whereas natural disturbance was the dominant factor during calving. Despite this negative influence on fidelity, caribou tended to demonstrate range fidelity even in study sites most impacted by human activities. Habitat disturbances could produce two possible outcomes for caribou conservation: (1) a trend for females to reduce home-range fidelity which could translate into lower calf and female caribou survival through reduced familiarity with food distribution, escape cover and predation risk and (2) a global tendency to maintain range fidelity even in a drastically modified landscape which could turn into an ecological trap, particularly for calves when predation risk increases due to increased black bear density in early successional forests. Taking range fidelity behavior into consideration during forest management planning could direct conservation efforts toward the best available sites and therefore facilitate caribou persistence in managed landscapes.     

Tree species affect atmospheric CH4 oxidation without altering community composition of soil methanotrophs

Plant species exert strong effects on ecosystem functions and one of the emerging, and difficult to test hypotheses, is that plants alter soil functions through changing the community structure of soil microorganisms. We tested the hypothesis for atmospheric CH₄ oxidation by using soil samples from a Siberian afforestation experiment and exposing them to ¹³C-CH₄. We determined the activity of the soil methanotrophs under different tree species at three levels of initial CH₄ concentration (30, 200 and 1000 ppm) thus distinguishing the activities of low- and high-affinity methanotrophs. Half of the samples were incubated with ¹³C-enriched CH₄ (99.9%) and half with ¹²C-CH₄. This allowed an estimation of the amount of ¹³C incorporated into individual PLFAs and determination of PLFAs of methanotrophs involved in CH₄ oxidation at the different CH₄ concentrations. Tree species strongly altered the activity of atmospheric CH₄ oxidation without appearing to change the composition of high-affinity methanotrophs as evidenced by PLFA ¹³C labeling. The low diversity of atmospheric CH₄ oxidizers, presumably belonging to the UCSα group, may explain the lack of tree species effects on the composition of soil methanotrophs. We submit that the observed tree species effects on atmospheric CH₄ oxidation indicate an effect on biomass or cell-specific activities rather than by a community change and this may be related to the impact of the tree species on soil N cycling.     

贵州纳雍珙桐自然保护区林木种质资源调查研究

纳雍珙桐自然保护区共有木本植物96科243属693种。其中,野生种类有661种,包括乔木类有202种,灌木类有365种,木质藤本有94种;栽培种类有32种。依据当前木材商品市场的标准,将区内202种乔木类树种分为:珍贵类7种,白木类11种,硬木类33种,一般用材141种,不作材用的有10种。     

Influence of tree crown characteristics on the local PM10 distribution inside an urban street canyon in Antwerp (Belgium): A model and experimental approach

Apart from influencing the amount of leaf-deposited particles, tree crown morphology will influence the local distribution of atmospheric particles. Nevertheless, tree crowns are often represented very rudimentary in three-dimensional air quality models. Therefore, the influence of tree crown representation on the local ambient PM₁₀ concentration and resulting leaf-deposited PM₁₀ mass was evaluated, using the three-dimensional computational fluid dynamics (CFD) model ENVI-met^® and ground-based LiDAR imaging. The modelled leaf-deposited PM₁₀ mass was compared to gravimetric results within three different particle size fractions (0.2–3, 3–10 and >10 μm), obtained at 20 locations within the tree crown. Modelling of the LiDAR-derived tree crown resulted in altered atmospheric PM₁₀ concentrations in the vicinity of the tree crown. Although this model study was limited to a single tree and model configuration, our results demonstrate that improving tree crown characteristics (shape, dimensions and LAD) affects the resulting local PM₁₀ distribution in ENVI-met. An accurate tree crown representation seems, therefore, of great importance when aiming at modelling the local PM distribution.     

桃树树体改造及长枝修剪关键技术

着重介绍桃树树体结构改造、枝组调整和处理以及长枝修剪的优点、要领,总结出桃树树体改造和长枝修剪应注意的问题等。