三角枫在高温汽蒸条件下的诱发变色

三角枫是一种易变色的木材,其变色在干燥过程中不易预防;若能在干燥过程中通过诱发变色使三角枫得到更为理想的颜色,可使三角枫获得更为广阔的应用前景.该文通过对三角枫在高温(96～99℃)汽蒸条件下诱发变色视觉物理参数以及红外光谱和扫描电镜的分析,得出了三角枫在高温汽蒸条件下颜色的变化趋势和诱发变色机理.结果表明,三角枫在高温汽蒸条件下的诱发变色是可行的,在诱发变色过程中木材颜色变化趋势是红色和红褐色.三角枫在高温汽蒸条件下诱发变色机理为:①高温汽蒸加速了三角枫中多元酚类物质以及无色花色素和单宁等氧化反应,使三角枫发生红色变色;②三角枫经高温汽蒸处理,羟基经氧化转化为羰基、羧基、酯基和酮基等,使木材的颜色发生变化.     

不同栽培基质对十月秋枫容器苗生长的影响

试验以十月秋枫为试材,研究了10种基质配方对十月秋枫容器苗生长的影响.结果表明,不同基质配方促进十月秋枫容器苗生长的作用明显,幼苗主要生长指标如主干高、主干叶片数、主干叶面积、侧干高、侧干叶片数都出现了显著变化.其中以50％的桂花枯枝落叶碾碎制成的粉末加50％的腐熟肥料组成的混合物:园土=40:60的配方促进十月秋枫容器苗生长的效果最好,其次是泥炭∶桂花枯枝落叶碾碎制成的粉末∶河沙=10∶20∶70的配方.     

牛背梁自然保护区血雉种群数量与分布

2009年1月～2010年12月,采用路线调查与访问调查相结合的方法,对牛背梁保护区血雉种群数量与分布情况进行了调查。调查结果显示,血雉仅分布于牛背梁保护区境内秦岭主脊以南海拔1 725～2 615m的地带,而以光头山、小甘沟、牛背梁与花门楼地区海拔2 115～2 387m的分布最为集中。血雉在区内的分布面积为41.7km2。根据调查数据计算,牛背梁保护区境内血雉的间接数量为1 902只,在整个保护区内的平均分布密度为11.288只/km2。     

林蛙害虫大黄缘青步甲生物学特性初步观察与防治

以防治为害林蛙的大黄缘青步甲为研究对象,采用实验室饲养和养殖场野外观察相结合的研究方法,对大黄缘青步甲的形态特征及其生物学特性进行了系统的研究。结果表明,在浙江桐庐,该虫1年发生1代,以成虫在土壤、枯枝落叶中越冬;幼虫共3龄,幼虫期8～10d;在林蛙养殖场,幼虫会咬林蛙,吸血、吃肉,7月上旬是幼虫集中为害期。同时,根据大黄缘青步甲发生规律、生物学特性,提出了以预防为主的综合防治措施。     

三角枫在干燥过程中变色机理的研究

该文通过对三角枫木材抽提物的定性分析、红外光谱分析、不同变色试材的扫描电镜分析 ,以及不同干燥工艺条件下三角枫颜色的变化分析 ,探讨了三角枫在干燥过程中的变色机理 .研究结果表明 :三角枫在干燥过程中的变色是一个复杂的变色过程 ,主要是由于三角枫中的多元酚物质以及无色花色素和单宁在一定的温度和湿度条件下的氧化反应 ,以及三角枫中的苯环、酚羟基、羟基—OH、羰基—CO等发色团与助色团的变化 ,使三角枫在干燥过程中变色 .     

Growth and nutrition of young European ash (<Emphasis Type="Italic">Fraxinus excelsior</Emphasis> L.) and sycamore maple (<Emphasis Type="Italic">Acer pseudoplatanus</Emphasis> L.) on sites with different nutrient and water statuses

This study aimed to improve knowledge about the nutritional status, site requirements and site classification for European ash (Fraxinus excelsior L.) and sycamore maple (Acer pseudoplatanus L.) by reinvestigating young plantations from 1991/1992 on windfall-affected areas in Bavaria/Germany after another decade. Compared to the first survey in 1995, most stands improved their nutritional status until 2006. With the data set of element concentrations in leaves of ash and sycamore available, the range of adequate nutrition could be determined for these species in the pole stage phase. Both species show considerable height growth on a wide range of sites. Mean annual height growth of dominant sycamore trees increased with rising foliar N or P concentrations but not for Ca, Mg, K, Mn, Fe and Al. For ash, there was no relationship between the foliar nutrient level of any element and mean annual height growth. However, total height around age 20 was favourably influenced by high base saturation and a good water supply at well-drained sites. On acid soils, where nutrients are delivered by subsurface water flow, well-growing stands are found as well. Soil water status according to the state forest soil classification had no significant impact on mean annual height growth. Ash and sycamore show reduced productivity on some (moderately) dry soils and fail on poorly drained moist sites. Based on these results, the classification of forest sites suitable for ash and sycamore within the Bavarian study sites was revised. Dedicated to Professor Dr. Karl-Eugen Rehfuess on his 75th birthday.     

Modelling the effect of climate on maple syrup production in Québec,Canada

Due to the exceptional sweetness of its sap, sugar maple (Acer saccharum Marsh.) is economically exploited at a commercial scale for maple syrup production in northeastern North America. Approximately 80% of world production is realised in the province of Quebec, Canada, where it is economically important for rural communities. Despite important financial investments in industrial infrastructure over recent decades, the maple syrup yield (ml of sap/tap/year) has followed a general declining trend over the last 15 years, presumably because of unfavourable climatic conditions. In this study, the relationship between climate and maple syrup yield by tap for the whole province was investigated.     

江苏大丰麋鹿保护区有效管理的成就和展望

为了麋鹿的更好保护和充分利用,以及江苏大丰麋鹿保护区的良好发展,通过实地调查、人员访谈、资料查询等方法对大丰麋鹿保护区的成功经验和存在的不足进行分析,提出未来的改进办法。大丰麋鹿保护区成功地把野外已灭绝了的我国特有动物麋鹿回归大自然,这是世界自然保护事业中一个具有划时代意义的事件。文中首先介绍了该自然保护区在麋鹿的保护和繁衍、科研监测、教育培训、资源持续利用、生态旅游等方面所取得的成绩,其次在管理方面提出了5方面建议,供有关方面参考:一是为建立共管体制,作出试验示范;二是为适当调整保护区内功能区域的划分;三是加强对麋鹿保护与持续利用的研究;四是加强野生生物利用的研究;五是建立有机农业生产基地和观光农业园区。     

Induced discoloration of buerger maple during drying process

Buerger maple (Liquidambarformosana Hance) is a kind of wood that is easily discolored. This paper tries to obtain satisfactory color and a broad prospect in the utilization of buerger maple by induced discoloration. The authors analyze the mechanism of induced discoloration of buerger maple based on the analysis of visual physical parameter, the infrared spectrum (IRS) and the scanning electron microscope (SEM) under different drying conditions. The result shows that it is feasible to induce discoloration during the drying process. The wood color tends to be red and fuscous during inducing discoloration of buerger maple.The induced discoloration mechanism is: 1) the high temperature and humidity accelerates the oxidation reaction of polyphenol,leuco-fancy pigment and tannin, which changes the wood color to red; 2) the hydroxy (-OH) is oxidized and the carbonyl (-C=0),carboxyl (-COOH), ester and ketone groups form during the high temperature steaming, which results in wood piece discoloration.