世界国家公园的回顾与展望   总被引：12，自引：5，他引：12  

卢琦  赖政华  李向东 《世界林业研究》1995,8(1):34-40

国家公园的创意源自美国,世界上现有１００多个国家建有国家公园和准国家公园１２００余座。国家公园的主脉是自然保护和公众游乐。国家公园的管理体制各国有别,但总体上可归纳为中央集权制、地方自治型和综合管理型３大类;无论哪种类型都离不开林业部门的参与和合作。文中介绍了美国国家公园在人事制度,许可证制度和客流量限制等方面所采取一些具体措施,同时也指出了国家公园面临的困难和问题及未来发展的目标和走向。  相似文献   

肚倍蚜的生物学研究 Ⅲ.种群数量变动^*   总被引：1，自引：0，他引：1       下载免费PDF全文

赖永祺  张燕平  方英  焦懿  李正洪  陈宝珊 《林业科学研究》1993,6(2):151-156

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Interactive effects of leaf age and self-shading on leaf structure,photosynthetic capacity and chlorophyll fluorescence in the rain forest tree,Dryobalanops aromatica     

Ishida A  Uemura A  Koike N  Matsumoto Y  Hoe AL 《Tree physiology》1999,19(11):741-747

In the tropical canopy tree, Dryobalanops aromatica Gaertn. f., upper-canopy leaves (UL) develop under sunlit conditions but are subjected to self-shading within the crown as they age. In contrast, lower-canopy leaves (LL) are exposed to uniform dim light conditions throughout their life span. By comparing leaf morphology and physiology of UL and LL, variations in leaf characteristics were related to leaf age and self-shading. Mass-based chlorophyll (chl) concentration and the chlorophyll/nitrogen (chl/N) ratio were lower and the chl a/b ratio was higher in UL than in LL. In UL, the chl/N ratio gradually increased and the chl a/b ratio gradually decreased with leaf aging, whereas these ratios remained unchanged with leaf age in LL. The effective quantum yield of photosystem II (PSII) (DeltaF/F(m)') at a given irradiance remained unchanged with leaf age in LL, whereas DeltaF/F(m)' changed with leaf age in UL. These data indicate N reallocation within the leaves from carbon fixation components to light harvesting components and a dynamic regulation of photochemical processes of PSII in response to increased self-shading of UL. Despite the difference in light environment with leaf age between UL and LL, maximum photosynthetic rates and nitrogen-use efficiency decreased with leaf aging in both UL and LL. Constancy in the chl/N ratio with leaf age in LL indicated that the decrease in photosynthetic capacity was caused by effects other than shading, such as leaf aging. We conclude that N reallocation and acclimation of PSII to self-shading occurred even in mature leaves, whereas the change in photosynthetic capacity with leaf age was more conservative.  相似文献   

角倍蚜瘿内世代生物学及角倍生长的初步研究   总被引：1，自引：0，他引：1       下载免费PDF全文

赖永祺  彭兴民  李正洪 《林业科学研究》1988,(3):309-314

角倍蚜Schlechtendalia chinensis(Bell)在盐肤木Rhus chinensis Mill.上所形成的倍子(即角倍)约占全国五倍子总量的80％,经济价值很大。该倍蚜的生活周期属异寄主全周期型,虫型多样,生活习性复杂。在其生活年史中,春季有翅孤雌蚜(春迁蚜),迁飞到第一害主盐肤木上产雌雄性蚜,经一月左右(一般在夏初),雌蚜生殖,产下的干母爬到嫩叶上取  相似文献   

不同种源翅荚木的抗寒性   总被引：8，自引：0，他引：8  

何小勇  柳新红  袁德义  谭晓风  赵思东  张琳  魏来 《林业科学》2007,43(4):24-30

以5个种源的翅荚木叶为材料,采用叶片离析法和石蜡制片技术观测叶片结构特征、电导率法测定其半致死温度、差示热量扫描仪测定其过冷点温度,并结合田间试验分析不同种源翅荚木苗期的抗寒性及其与叶片结构的关系.结果表明:湖南通道翅荚木种源抗寒性最强,苗期在湖南株洲无冻害,在浙江丽水冻害率为4.83%,极显著低于其他种源;其叶片半致死温度为-5.34 ℃,过冷点温度为-15.04 ℃,均低于广东翁源和广西忻城种源. 不同种源翅荚木叶片细胞结构紧密度(CTR)和疏松度(SR)与种源的抗寒性有一定的关系,CTR值越大、SR值越小,种源的抗寒性越强.  相似文献   

Active X控件实现工程索道线路计算程序中数据的输入输出     

左来  朱洪前 《森林工程》2006,22(4):29-31

线路计算是工程索道设计中计算量最大的内容。本文利用Visual C＋＋6．0的Active X控件，结合单索循环式工程索道线路计算的编程，介绍如何实现程序中数据的输入输出。  相似文献   

Essential oil from the leaves of Cryptomeria japonica acts as a silverfish (Lepisma saccharina) repellent and insecticide     

Sheng-Yang Wang  Wan-Chi Lai  Fang-Hua Chu  Chien-Tsong Lin  Shi-Yen Shen  Shang-Tzen Chang 《Journal of Wood Science》2006,52(6):522-526

This is the first article to report the evaluation of a natural product used as an antisilverfish agent. Silverfish (Lepisma saccharina), primitive wingless insects, feed on a variety of materials, including paper, cotton, starch, and cereals. They can be a problem in libraries and other places where books, documents, and papers are stored. In this pilot study, the essential oil from leaves of Cryptomeria japonica was investigated to test its properties as a silverfish repellent and insecticide. The results from a repellency bioassay show that the essential oil significantly repelled silverfish. The repellent activity was 80% at a dosage of 0.01 mg/cm³. When silverfish were exposed to a concentration of 0.16 mg/cm³ of essential oil, they were killed within 10h. The chemical composition of essential oil, the emissions from a test chamber, and the residue left on filter papers previously soaked with the essential oil in a chamber were analyzed by gas chromatography-mass spectrometry. The components of the essential oil were found to be: elemol (18.22%), 16-kaurene (11.63%), 3-carene (9.66%), sabinene (9.37%), 4-terpineol (9.06%), β-eudesmol (5.70%), α-pinene (5.62%), and limonene (5.26%). Only some constituents of the essential oil compounds collected by solid-phase microextraction were found to be emitted in the test chamber. The main constituents were: 3-carene (21.03%), p-cymene (10.95%), limonene (9.49%), β-myrcene (9.39%), γ-terpinene (9.10%), α-terpinene (8.57%), and 4-terpineol (7.97%).  相似文献   

水曲柳无性系初级种子园营建技术标准   总被引：1，自引：0，他引：1  

李京  苏明焱  罗旭 《中国林副特产》2007,(5):30-32

在种源选择和子代测定,并吸收前期水曲柳种子园营建技术成果、文章的基础上,参考国内外其它树种种子园营建技术、国家地方相关标准、规程和有关政策,对水曲柳无性系种子园的规划设计、建园及经营管理技术进行了明确界定与规范,制定水曲柳无性系种子园营建技术标准,旨在为生产部门建立水曲柳无性系种子园提供技术支撑。  相似文献   

枣树绿枝扦插试验研究   总被引：1，自引：0，他引：1  

来锡福  李柏春 《甘肃林业科技》1995,20(4):1-4

本试验选用当年生半木质化枣头发育枝作扦插材料，用不同激素、不同浓度进行处理，以河沙做扦插基质；用塑料小拱棚和人工洒水调控温湿度；用竹帘搭棚遮荫简单行的方法，使枣树绿枝扦插当年成活率达８５％以上。冬季采用覆麦草越冬。  相似文献   

肚倍蚜生物学研究Ⅰ.生活史^*   总被引：4，自引：0，他引：4       下载免费PDF全文

赖永祺  张燕平  李正洪  方英  陈宝珊 《林业科学研究》1992,5(5):554-558

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