Age estimation of different tree species using a special kind of an electrically recording resistance drill     

《Urban Forestry & Urban Greening》2018

The determination of tree age is an important issue for urban green planning, forestry and dendrology; finding non-destructive and quasi-non-destructive methods for this purpose is of great theoretical and practical importance. The resistance drilling method is quasi-non-destructive because the average diameter of an opening that remains after drilling does not exceed 3 mm. Do electrically recording resistance drills allow precise assessment of tree age? The aim of this study is to assess the accuracy of determining the number of tree rings based on an examination of this special kind of drilling resistance profiles for three tree species, the pine Pinus sylvestris L., the oak Quercus robur L., and the birch Betula pendula ROTH. In 2015 and 2016, 15 pine trees, 15 oak trees, and 15 birch trees were randomly selected. For each studied tree, a measurement was conducted using the electrically recording resistance drill IML-Resi E400 with a flat-tipped 1.5/3 mm steel needle (research sample), and an increment core was taken (reference sample). The drill used was not a real Resistograph^®. The analysis of the E400-profiles underestimated the number of tree rings; the mean bias error (MBE) values were –6.5, –2.5, and –6.0 years for pine, oak, and birch, respectively. The proportion of investigated trees with less than five years difference between the research and reference samples varied from 38.4 (birch) to 66.7 (oak) percent. The accuracy of tree age determination was lowest for birch and highest for oak. The binomial generalised linear model (GLM) revealed that the most accurate tree age assessments were obtained from tree rings wider than 2 mm. The measurements clearly showed that the electrically recording resistance drill IML-Resi E400 enables a quick, although approximate, tree age assessment. Future research should concentrate on electronically regulating and recording drills, providing a higher spatial and signal resolution, and a stronger correlation to wood density.  相似文献   

不同秧龄对沿江地区双季晚稻秧苗素质及产量的影响   总被引：1，自引：0，他引：1  

潘志军  吴小文  陈刚  吴晨阳  张晓红  尹玲  吴文革  吕和平 《中国稻米》2017,(6):97-100

以早熟高产品种上农粳2号和镇稻18为材料,采用常规毯苗机械栽插,分别设置20 d、24 d、28 d、32 d等4个秧龄处理,研究不同秧龄对沿江地区双季晚稻秧苗素质、生育进程、茎蘖动态及产量构成的影响。结果表明,随秧龄天数增加,参试品种的绿叶数、茎基宽和根系盘结力均逐渐升高;与20 d、24 d和28 d秧龄的处理相比,32 d秧龄处理的成熟期提前4~5 d,茎蘖高峰期提早15 d左右,结实率显著升高;与24 d秧龄处理相比,上农粳2号和镇稻18在32 d秧龄处理下的产量分别提高10.26%和20.82%。在秧苗强化化控和苗床管理的条件下,安徽沿江地区常规毯苗机插的栽插秧龄可延长至32 d。  相似文献   

Sacred sites as habitats of culturally important plant species in an Indian megacity     

《Urban Forestry & Urban Greening》2018

Cultural ecosystem services related to urban green spaces contribute significantly to liveable cities. While previous studies highlight the intersection of cultural ecosystem services with societal values, spiritual or religious values associated with urban nature have received less attention. In India, as in other parts of the world, sacred sites are known for their biological richness, but analyses from urban sacred sites are largely missing. Based on a stratified random sampling approach, we analysed the cultivated and wild plant species assemblages of 69 sacred sites in the megacity of Bengaluru, India, in relation to biological and cultural features, and parameters related to the urban matrix and type of sacred sites (temple vs. katte). Unlike other urban studies, we found a dominance of native species in the cultivated and spontaneous species pools (121 species in total), with Ficus religiosa and Azadirachta indica as most frequently planted species. Culturally relevant species prevailed in the species pool (89%), with overlaps between religious (36%), medicinal (50%) and ornamental (62%) plants; only 11% of species were weeds. Urban matrix parameters (age of development, housing density) and size and type of sacred sites were related to differences in species assemblages. We identified key species for different classes of age and housing density, and for types of sacred sites. Our study demonstrates that urban sacred sites have an important potential in harbouring both native and culturally significant species that can support urban livelihoods in developing countries by a range of cultural and provisioning ecosystem services, including medicinal uses. As such sites are conserved by communities for spiritual or cultural beliefs, local biodiversity can be enhanced, e.g. by adapting management practices through community participation. This would strengthen the important contribution of sacred sites within the green infrastructure of rapidly growing megacities.  相似文献   

Radioisotope and stable isotope ratios (Δ14C, δ15N) suggest larval lamprey growth is dependent on both fresh and aged organic matter in streams     

Thomas M. Evans  Amber R. Bellamy  James E. Bauer 《Ecology of Freshwater Fish》2019,28(3):365-375

Lampreys have a complex life cycle which includes a multi‐year infaunal larval stage (ammocoete). Gut content analysis has generally identified detritus (i.e., unidentifiable organic matter) as the major dietary component to ammocoetes, though algae can also be important. However, gut content preserves only a snapshot of the animal's diet and does not reflect assimilated material. In order to better characterise the nutritional sources supporting ammocoete growth, we analysed ammocoete body tissue and potential dietary sources at two streams using natural Δ¹⁴C and δ¹⁵N to estimate time‐integrated nutritional support. Bayesian isotope mixing models revealed differences in the importance of sources supporting ammocoetes between sites. Ammocoetes from a stream in a mixed land usage area (~50% agriculture, ~40% forest and ~10% developed) were primarily supported (mean: ~50%) by fresh terrestrial organic matter but were also supported by substantial contributions (mean: ~30%) by aged organic matter (AOM) and autochthonous material (algae; mean ~20%). In a predominantly forested (~90%) headwater stream, different modelling scenarios (uninformed or informed priors) suggested that algal support of ammocoete nutrition ranged from 7% to 45%. However, the model relying on informed priors developed from gut content analysis produced the low estimates, suggesting these were more reliable. When algae were a minor component of the nutrition at the forested site, ammocoetes were highly dependent on AOM (83 ± 26%; mean ± SD). Based on these findings, ammocoete growth and development are predicted to be strongly influenced by both land use and the availability of allochthonous and autochthonous materials of varying ages within streams.  相似文献   

Validation of the otoliths for age determination in Barbus sclateri (Günth.)     

C. Escot  C. Granado-Lorencio 《Ecology of Freshwater Fish》2001,10(2):122-126

Abstract – Otoliths were used to explore the timing of annulus formation in Barbus sclateri. Lapillus exhibited opaque and translucent zones whose combination was formed once a year. Opaque zones appeared formed from July and January, and the translucent ones from February to June. We describe a procedure to assess age by using the number of annulii, the condition of the otolith's edge and the capture date. The use of otoliths for age determination in this cyprinid endemic to the Iberian Peninsula provides a useful alternative to the traditional methods of scale reading. ^Note  相似文献   

新的信息资源环境下图书馆员角色转变的思考   总被引：1，自引：0，他引：1  

和艳会  惠青  杨慧 《农业网络信息》2009,(4)

本文分析了信息时代图书馆员角色转变的几个重要因素及特点,揭示了新时代图书馆员应承担的几种重要角色,对信息时代图书馆员的发展进行了探讨.  相似文献   

蛋鸡血清硷性磷酸酶变化规律的研究     

孙宪如  卢一凡  孙姝芬  赵立富 《中国兽医学报》1989,(3)

本试验以京白Ⅲ系为试验材料,测定了四个时期的血清AL P活性,研究了其变化规律。结果表明,AL P同工酶型快型酶活性显著高于慢型。年龄、同工酶型及年龄×同工酶型互作对AL P活性有显著影响。AL P活性与产蛋量间遗传相关表现为,在生长期为正,而产蛋期为负。四个年龄中,AL P做为间接选择指标,以6周龄为最佳.  相似文献   

小家鼠胴体重指标划分种群年龄的研究     

潘世昌  杨再学  杨秀群  归贤祥  李梅 《贵州农业科学》2006,34(Z1):18-20

对2005年1~12月在贵州省息烽县鼠情监测点捕获的258只小家鼠标本,以胴体重为指标,参照繁殖状况,用胴体重频次分配方法将小家鼠划分为4个年龄组,其划分标准为,幼年组(Ⅰ):胴体重≤6.49 g;亚成年组(Ⅱ):6.50~9.99 g;成年组(Ⅲ):10.00~13.49 g;老年组(Ⅳ):≥13.50 g。不同年龄组繁殖力差异显著,胴体重随种群年龄的增长而不断增加,各年龄组胴体重与体重、体长、尾长均呈正相关性,且与体重相关性达极显著。研究认为,采用胴体重划分小家鼠年龄是可行的,方法简便,易于操作。  相似文献   

枣品种枣股有效结果年龄与丰产性的关系   总被引：2，自引：0，他引：2  

毕平  康振英 《山西农业科学》1993,21(1):48-51

根据枣股的有效结果年龄,把调查的125份枣品种分为4个类型:1～3龄枝结果为主;2～9龄枝结果为主;1～9龄枝结果为主和2～6龄枝结果为主,它们分别形成各类品种产量的85%以上。“1～3”型品种早果性强,早丰性好.但成龄树立体结果能力极差;“2～9”型品种早果性差,但开始结果后产量上升快丰产稳产:“1～9”型品种多数为小果型品种,虽早果性强,但早丰性差,盛果期树立体结果能力强;“2～6”型品种早果性较差,并有不同程度的大小年现象。  相似文献   

人工培植羊体羊黄的研究     

谢仲权  丁明星  孙家发  王惠川  张永红  谢富强  张合 《北京农学院学报》1993,(2)

本试验以外科手术方法在北京农户所养绵羊胆囊内放人异物网核和注入致黄菌(SEBF8,50亿/ml),诱发羊黄,均获成功.其间,对术前术后血清胆红质、胆固醇、谷草转氨酶和GROS反应等项进行测定.结果表明:上述各项指标在术后8天内与术前比,均有降低,差异显著,但以后逐渐恢复正常.而体重、临床表现,以及饲养指标本出现异常.预示着,人工培植羊体羊黄可行.同时,本试验还为进一步提高人工培植羊黄的产黄量,提供了参考数据.  相似文献