环球佳丽“靓”银滩——2006环球比基尼小姐大赛圆满结束

2006环球比基尼小姐大赛总决赛于8月26日晚在中国（北海）落幕，乌克兰小姐欧丽娜摘得桂冠，被授予“珍珠美后”（QUEEN PEARL）及“北海市旅游形象大使”称号。     

杜仲生产技术研究综述

杜仲生产技术研究综述王华田，高景昌（山东农业大学，泰安，２７１０１８）杜仲（ＥｕｃｏｍｍｉａｕｌｍｏｉｄｅｓＯｌｉｖ，）是我国特有经济树种，是珍贵的木本中药材。我国劳动人民栽培、研究和利用杜仲已有两千多年的历史，积累了丰富的经验。杜仲自１９世纪引入欧...     

欧盟只允许合法的木材产品进入其市场

自愿伙伴关系协议（VPAs）规定，通过设立许叮证制度只允许经过验证的合法木材产品才能出口到欧嗌。作为交换，欧盟将促进协议所涵盖的木制品进入其市场。     

发现于浙江的2种归化植物新记录

报道了2种发现于浙江的新归化植物，其中沼生丁香蓼Ludwigia palustris (L.) Elliott为中国大陆归化植物新记录，欧毛茛Ranunculus sardous Crantz为浙江归化植物新记录。附有彩色照片。凭证标本分别藏于浙江自然博物院（ZM）和浙江农林大学植物标本馆（ZJFC）。     

欧洲温带树木中微量营养物浓度水平差异显著

瑞典隆德大学植物生态学和系统学系的科学家A．Hagen-Thorn等，最近研究了6种欧洲树木，包括欧洲白桦（垂枝桦）（Betula pendula）、欧洲白栎（英国栎）（Quercus robur）、欧洲白蜡树（Faxinus excelsior）、欧洲山毛榉（欧洲水青冈）（Fagus sylvatica）、心叶椴（欧椴）（Tilia cordata）和欧洲云杉（挪威云杉，白木）（Picea abies）的叶片和杆材（含树皮）中的微量营养物浓度。这些树木被种植在3个不同国家的6个地点的相同类型的土壤上。     

山楂园的百脉根生草覆盖效应研究

山楂园的百脉根生草覆盖效应研究丁玉川，俞小秋（山西省农科院土壤肥料研究所，太原０３００３１）百脉根（ＬｏｔｕｓｃｏｒｎｉｃｕｌａｔｕｓＬ．）属多年生豆科牧草，原产欧亚温暖地带，目前欧、美、澳和南亚已大面积种植，也适应我国南方、西北和华北地区。该草根系...     

有机枸杞生产关键技术

在科技攻关计划项目支持下，宁夏农林科学院枸杞研究所于银川市西夏区本所基地建成40hm^2有机枸杞种植示范基地。基地先后获得美国有机农业条例（NOP）、欧有机农业法规（EU2092／91）、中国国标《有机产品黻证，总结出“有机枸杞生产技术”，形成宁夏地方标准DB64／T500《有机枸杞生产技术规程》。     

林产工业中具有巨大发展潜力的工业──天然香料工业

林产工业中具有巨大发展潜力的工业─—天然香料工业蔡祖善（林业部林产工业规划设计院北京１０００１０）编者按在香料发展史上，中国是最早开发、生产和使用香料的国家之一，而今天则处于落后的地位。世界庞大的香料市场为欧、美少数西方国家所垄断，数以百亿美元的巨额...     

自治区主要有益动物名录

翼手所有种（10种），食央目所有种（4种）大杜鹃、中杜鹃、小杜鹃、欧夜鹰、楼燕、小白腰雨燕、戴胜、啄木鸟科所有种（9种），百灵科所有种（19种）、燕科所有种（5种）、旭鸽种所有种问2种）、伯劳科所有种（4种）、金黄鹤、粉红凉鸟、紫翅惊鸟、家八哥、喜鹊、黑尾地鸦、白尾地鸦、揭背似地路、秃咀乌鸦、寒鸦、渡鸦、河鸟、揭河鸟、鹤亚科所有种（28种）、文须雀、山鸡、莺亚科所有种（30种）、鹤亚科所有种（4种）、山雀科所有种（8种）、普通鹏、红翅旋壁雀、旋木雀、高山族木雀、攀雀、鸥属所有种（19种）铁爪吗、雪鹏．中国林蛙、…     

沙棘人工林水土保持效益分析

沙棘人工林水土保持效益分析邵云（辽宁省干旱地区造林研究所１２２４００）沙棘是胡颓子科沙棘属的一种灌木或小乔木，原产欧、亚两洲。我国多分布在华北、西北。自５０年代以来，辽宁省干旱地区造林研究所从酉北地区引进栽植，并进行了大量的试验研究和推广工作，目前在...     

Antioxidant activity of Erica arborea

The antioxidant properties of the methanol extract of leaves and flowers of Erica arborea and the ethyl acetate, butanol and water soluble fractions were investigated. The ethyl acetate extract was found to be the richest for phenolic and flavonoid content which showed the highest antioxidant activity.     

Spatial and temporal patterns in structure and diversity of Mediterranean forest of Quercus pyrenaica in relation to fire

The main objective of this work is to analyze the spatial and temporal response of Q. pyrenaica community to fire. In order to do so, an ecological characterization of 15 forests in different succession stages (5 Initial: 0–20 years, 5 Medium: 20–60 years and 5 Mature: over 60 years), paying special attention to structural and diversity features, was carried out. The results show that temporal changes are very important, and particularly affect the structure and relative abundance of the vegetation. The main differences consist in the change from a homogenous structure, with high cover and overlayering of woody species, at Initial stage, to a more pluristratified, complex and organized structure, with lower cover and overlayering of woody species at Mature stage. The changes in abundances showed a decrease in shrubby species, such as the Erica australis, Genista florida and Erica arborea at Initial stage, and the incorporation of tree species, such as Crataegus monogyna, Acer pseudoplatanus and Alnus glutinosa at Mature stage. However, there are no significative differences between stages for specific richness and diversity values. Spatial heterogeneity is high and similar in all three defined stages.     

Germination in five shrub species of Maritime Pine understory—does seed provenance matter?

? Context

Maritime Pine forests cover important mountain areas in Portugal and are known to be a particularly fire-prone forest type. Understory composition plays an important role in maintaining biodiversity and ecosystem services after recurrent wildfires.

? Aims

This study aims to improve the knowledge on the germination ecology of understory species of Maritime Pine forests, focusing on the importance of seed provenance, including in relation to germination enhancement by heating.

? Methods

The selected species were Cistus ladanifer L., Erica australis L., Erica umbellata L., Pterospartum tridentatum L. (Willk), and Genista triacanthos Brot. Seeds were collected from two or three distant populations. Besides a control treatment, two heating regimes were applied, i.e., 100°C during 5?min and 80°C during 30?min.

? Results

Heating treatments significantly enhanced germination in four out of the five species. Differences between provenances were most evident for C. ladanifer and E. australis, especially following the heating treatments. Overall, the seeds from the southern provenances germinated better and, at the same time, were smaller.

? Conclusion

The present results confirmed that seed provenance should not be ignored as a key factor in germination ecology, so that further work is needed to untangle the roles of environmental and genetic factors in the observed differences between provenances.     

Isotopic carbon discrimination and leaf nitrogen content of Erica arborea L. along a CO(2) concentration gradient in a CO(2) spring in Italy

We studied a Mediterranean species (Erica arborea L.) growing in a CO(2) spring in Italy that was naturally exposed for generations to a gradient of atmospheric CO(2) concentrations. The CO(2) concentration gradient to which different individual plants were exposed was determined by an indirect method based on radioisotope analysis. The stable carbon isotope ratio of sampled leaves was determined by mass spectrometry, and isotopic discrimination was then calculated. Leaf nitrogen, specific leaf area, total soil nitrogen, soil organic matter content and soil pH were also measured. In one group of plants, grown on a homogeneous soil and exposed to moderate CO(2) enrichment, isotopic discrimination was significantly reduced in response to increasing CO(2) concentrations, whereas the intercellular CO(2) concentration and leaf nitrogen content were almost unaffected. In a second group of plants, grown along a gradient of CO(2) concentration and soil nitrogen content, leaf nitrogen content was reduced when nitrogen availability was limiting. However, when soil nitrogen was available in excess, even very high CO(2) concentrations did not result in increased discrimination or reduced leaf nitrogen content in the long term. The results are discussed with respect to current theories about the long-term CO(2) response of plants based on several years of experimentation with elevated atmospheric CO(2) concentrations under controlled conditions.     

Fire-driven oak regeneration in French Mediterranean ecosystems

Regeneration by seeds for cork oak (Quercus suber) and companion oaks (holm oak Quercus ilex and downy oak Quercus pubescens) is likely to be poor in the fire-prone Maures massif (southern France) but the causes are poorly known. Our objective was to assess the effective recruitment for these three oak species and their temporal pattern of recruitment, in order to determine the main limitation factors and the regeneration window of each species. We studied oak recruits (height <3 m) in naturally regenerated populations according to a gradient of fire recurrence and in five main vegetation types including shrublands and mixed mature woodlands. Fire recurrence was the main explanatory factor of oak recruitment, either directly or through vegetation type and microsite characteristics. The results indicate nil to low recruitment for holm oak and downy oak in shrublands, especially those recurrently burned and dominated by Cistus species. Cork oak recruited better than the other oaks in medium and high shrublands dominated by Erica arborea. In contrast, recruitment was high for holm and downy oak in mixed oak stands and mixed pine-oak stands that have not burned for decades. Microsite conditions such as coverage by litter and shrubs influenced oak recruitment, whereas landscape configuration and stand basal area had no influence. Our results suggest that strategic shrub-clearing, oak planting and protection of mixed oak woodlands as seed sources would help maintaining oak populations in the woodland–shrubland mosaic.     

An alternative method to estimate zero flow temperature differences for Granier's thermal dissipation technique

Calibration of the Granier thermal dissipation technique for measuring stem sap flow in trees requires determination of the temperature difference (DeltaT) between a heated and an unheated probe when sap flow is zero (DeltaT(max)). Classically, DeltaT(max) has been estimated from the maximum predawn DeltaT, assuming that sap flow is negligible at nighttime. However, because sap flow may continue during the night, the maximum predawn DeltaT value may underestimate the true DeltaT(max). No alternative method has yet been proposed to estimate DeltaT(max) when sap flow is non-zero at night. A sensitivity analysis is presented showing that errors in DeltaT(max) may amplify through sap flux density computations in Granier's approach, such that small amounts of undetected nighttime sap flow may lead to large diurnal sap flux density errors, hence the need for a correct estimate of DeltaT(max). By rearranging Granier's original formula, an optimization method to compute DeltaT(max) from simultaneous measurements of diurnal DeltaT and micrometeorological variables, without assuming that sap flow is negligible at night, is presented. Some illustrative examples are shown for sap flow measurements carried out on individuals of Erica arborea L., which has needle-like leaves, and Myrica faya Ait., a broadleaf species. We show that, although DeltaT(max) values obtained by the proposed method may be similar in some instances to the DeltaT(max) predicted at night, in general the values differ. The procedure presented has the potential of being applied not only to Granier's method, but to other heat-based sap flow systems that require a zero flow calibration, such as the Cermák et al. (1973) heat balance method and the T-max heat pulse system of Green et al. (2003).     

Short-term effects of clear-cutting on the biomass and richness of epiphytic bryophytes in managed subtropical cloud forests

? Managed laurel forests in the Canary Islands have undergone clear-cutting with rotation periods of less than 30 y. Forest owners have recently requested a drastic reduction in the cutting interval. The effects of this new harvesting cycle on organisms like epiphytic bryophytes are not well known.

? This study investigates how time since last clear-cut, host species and characteristics of tree zones influence the biomass, cover and richness of epiphyte bryophytes in managed laurel forests in La Palma, Canary Islands. Four forest ages (8, 15, 25 and 60 y) and three host tree species (Erica arborea, Laurus novocanariensis and Myricafaya) were studied.

? Biomass, cover and richness of bryophytes increased through the chronosequence, both at the level of each plot and overall for L. novocanariensis. Most of the biomass (53%) and richness (81%) was concentrated in one of the tree species (L. novocanariensis), in plots for which 60 y had elapsed since the last clear-cutting. Trunks supported greater bryophyte biomass and richness than canopies, even in the oldest plots.

? Our results suggest that the current rotation periods used to manage laurel forests are insufficiently long to allow for complete reestablishment of epiphytic bryophyte assemblages.

     

Radial variation in sap flow in five laurel forest tree species in Tenerife,Canary Islands

Variations in radial patterns of xylem water content and sap flow rate were measured in five laurel forest tree species (Laurus azorica (Seub.) Franco, Persea indica (L.) Spreng., Myrica faya Ait., Erica arborea L. and Ilex perado Ait. ssp. platyphylla (Webb & Berth.) Tutin) growing in an experimental plot at Agua García, Tenerife, Canary Islands. Measurements were performed around midday during warm and sunny days by the heat field deformation method. In all species, water content was almost constant (around 35% by volume) over the whole xylem cross-sectional area. There were no differences in wood color over the whole cross-sectional area of the stem in most species with the exception of E. arborea, whose wood became darker in the inner layers. Radial patterns of sap flow were highly variable and did not show clear relationships with tree diameter or species. Sap flow occurred over the whole xylem cross-sectional area in some species, whereas it was limited to the outer xylem layers in others. Sap flow rate was either similar along the xylem radius or exhibited a peak in the outer part of the xylem area. Low sap flow rates with little variation in radial pattern were typical for shaded suppressed trees, whereas dominant trees exhibited high sap flow rates with a peak in the radial pattern. Stem damage resulted in a significant decrease in sap flow rate in the outer xylem layers. The outer xylem is more important for whole tree water supply than the inner xylem because of its larger size. We conclude that measurement of radial flow pattern provides a reliable method of integrating sap flow from individual measuring points to the whole tree.     

Dendrometric and dasometric analysis of the bushy biomass in Mediterranean forests

The aim of this study was to define the dendrometric and dasometric parameters of five Mediterranean bushy plant species, to make their environmental assessment and to determine correlations with LIDAR data. The species studied were: Quercus coccifera, Rosmarinus officinalis, Ulex parviflorus, Cistus albidus, and Erica multiflora. We calculated the global form factor for each species so as to be able to determine the volume of the plants by measuring their base diameter and length. The model volume closest to the real volume was the cylinder, which had form factor values of between 0.8 and 2.33. We also studied the evolution of the moisture content of the vegetation after cutting. The initial values were from 20 to 30%, with a dry density of 1 t/m³. We defined an occupation factor to determine the relationship between the real volume occupied by the plants in an area and a model volume (hemisphere, paraboloid, cone, and cylinder). The occupation factor was similar for the five species studied in dm³ of material per m³ of (model) apparent volume: 3.5 dm³/m³ for the cylinder; 12.5 dm³/m³ for the cone; 8.5 dm³/m³ for the paraboloid; and 14.5 dm³/m³ for the hemisphere. These factors enabled us to calculate the biomass contained in an apparent volume of bushes (including materials and hollows) by density. The prediction models tested in this study will thus serve to determine the biomass of a bushy forest area when the Canopy Height Model (CHM) is calculated from LIDAR data.     

Long-term understory recovery after mechanical fuel reduction in Mediterranean cork oak forests

In the Euro-Mediterranean region, mechanical fuel reduction is increasingly used in response to the mounting occurrence of catastrophic wildfires, yet their long-term ecological effects are poorly understood. Although Mediterranean vegetation is resilient to a range of disturbances, it is possible that widespread fuel management at short intervals may threaten forest structural complexity and the persistence of some plant species and functional types, with overall negative consequences for biodiversity. We used a chronosequence approach to infer woody vegetation changes in the first 70 years after understory clearing in upland cork oak (Quercus suber) forests, and to assess how these are affected by treatment frequency. Across the chronosequence there was a shift between plant communities with contrasting composition, structure and functional organization. Understory cover increased quickly after disturbance and a community dominated by pioneer seeder and dry-fruited shrubs (Cistus ladanifer, C. populifolius, Genista triacanthos, and Lavandula stoechas) developed during about 15 years, but this was slowly replaced by a community dominated by resprouters and fleshy-fruited species (Arbutus unedo, Erica arborea) >40 years after disturbance. During the first 15 years there were rapid increases in woody species richness, vertical structural diversity, cover by Q. suber juveniles and saplings, and shrub cover at <1.5 m strata, which levelled off or slightly declined thereafter. In contrast, tree species richness, tree density and density of arboreal A. unedo and E. arborea, vertical structural evenness, and cover at >1.5 m strata increased slowly for >50 years. Treatment frequency showed strongly negative relationships with species richness, structural diversity and evenness, and horizontal and vertical understory cover, particularly that of slowly recovering species. These findings suggest that fuel reduction programs involving widespread and recurrent understory clearing may lead to the elimination at the landscape scale of stands with complex multi-layered understory occupied by large resprouters and fleshy-fruited species, which take a long time to recover after disturbance. Fuel management programs thus need to balance the dual goals of fire hazard reduction and biodiversity conservation, recognizing the value of stands untreated for >50 years to retain ecological heterogeneity in Mediterranean forest landscapes.