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基于分数阶CV模型的木材缺陷图像分割算法 总被引：1，自引：0，他引：1
针对木材虫眼、死节、活节等缺陷,提出了一种可调分数阶CV模型木材缺陷图像分割算法。将RGB彩色图像用PCA灰度化,在GACV模型的基础上,对边缘检测项用CRONE模板作分数阶微分处理,并耦合区域检测项迭代求解水平集函数,得到收敛的目标轮廓曲线。试验结果表明,提出的算法边缘定位能力强,可扩展性好,性能优于CV模型,能很好地提取木材缺陷目标。 相似文献
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《绿色中国(A版)》2018,(16)
正浙江省龙泉市是浙江省最大的林区县(市)、全国南方重点林区县(市)之一,素有"浙南林海"之称。全市土地总面积456万亩。林木蓄积量1945万立方米、林木种质资源居浙江省首位;林业用地面积398.5万亩、毛竹林面积55万亩、森林覆盖率84.2%,均居浙江省第二。全市28.86万人口,农民占24万,农民人均耕地面积1.1亩,而林地面积达16.6亩,是耕地面积的15倍。林业人均收入占农村人均居民可支配收入的61%,九 相似文献
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自治区林业厅重点区域绿化办公室 《内蒙古林业》2013,(12):32-33
五原县地处河套平原腹地，辖8个镇、1个乡、1个农场，总土地面积380万亩，立地条件差、地势落差大、排水不畅、土壤盐碱度高，特别是高速、国省道、沿黄公路两侧，由于土地贫瘠、盐碱化程度更为严重，导致造林成活率、保存率不高．给全县的造林绿化工作带来了极大的影响。 相似文献
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对发展,人们通常用鲜活蓬勃的数字去评判和理解,但洪水、赤潮、沙尘暴、毒大米、毒奶粉、毒韭菜……一桩桩纠缠不休的自然灾害、此消彼长的人间悲剧正暗示着繁华的数字下面所埋藏的伤害、隐忧和危机。在为追逐“发展”而狂躁急奔的路上,我们为什么不能片刻地停下脚步,回望一下所做的一切是否已经远远悖离了祖先挣脱“茹毛饮血”的初衷?用抛弃了“质”的“量”去求得社会的可持续发展,难道不正是古人所嘲笑的“缘木求鱼”?今天, “量”和“质”的辩证,不但检验着人类的生存质量,更考量着人类的生存智慧…… 相似文献
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本文根据林木良种各具不同的经济价值、用途和不同的生理生态特性，指出不正确的造林技术会抵消良种的增益，只有适地适树适品种并采用与良种相配套的栽培技术──“良法”，才能使良种获得更好效益。 相似文献
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美洲黑杨及其杂种在世界和我国杨树栽培中的地位与作用 总被引：2，自引：0，他引：2
本文介绍了美洲黑杨的天然分布, 生长状况。西欧各国对其珍贵基因资源的重视和利用, 我国引种美洲黑杨的现状及其作用等, 并对我国进一步利用美洲黑杨的基因资源, 促进我国杨树栽培的发展提出了一些看法。 相似文献
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Li Shan-wen Zhang Zhiyi He Cheng-zhong An Xin-min Yu Zhi-shui Li Bai-lian 《中国林学(英文版)》2005,7(3):61-69
Twenty-five species and hybrids in Populus were used as parents, and 26 cross combinations, including more than 5 000 seedlings, were obtained by artificial cross breeding.
The length of infructescence, number of seeds per infructescence, thousand-seed weight, germination rate of seeds among these
cross combinations were tested. The results indicated that the cross combinational effects were significant for these traits,
and demonstrated that the length of infructescence, thousand-seed weight were positively affected by female parent. In addition,
seedling height, diameter above ground, diameter at breast height (DBH) of 17 cross combination progenies were investigated.
The analysis of mean and standard deviation of these three traits showed that seedling height, diameter above ground, DBH
had extensive variation among combinations and individuals within combination. Variance analysis and estimate of heritability
indicated that the three traits had wide variation and were controlled by heredity. It was feasible to select superior cross
combinations and seedlings. Further more, the result of multiple comparison showed that P. deltoides ‘Lux’ × P. deltoides ‘D324’, P. ussuriensis cl. ‘U4’ × P. deltoides ‘T66’, P. ussuriensis cl. ‘U4’ × P. deltoides ‘T26’, P. deltoides ‘Lux’ × P. ussuriensis cl. ‘U3’, (P. tomentosa × P. bolleana) × (P. alba × P. glandulosa), (P. alba × P. tomentosa) × (P. alba × P. glandulosa), and (P. alba × P. glandulosa ‘No. 2’) × P. tomentosa ‘Lumao 50’ were superior cross combinations with higher growth rate. Finally, 123 elite seedlings were selected for further
test.
[Supported by the Doctoral Foundation of Ministry of Education (Grant No. 200220022004) and the National “863” Project (Grant
No. 2002AA241071)] 相似文献
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Populus tomentosa was crossed with P. tremuloidis, P. grandidentata, P. alba × P. grandidentata and P. alba × Ulmus pumila in order to maintain its rapid growth and high wood quality and improve its resistance to cold. Two methods were used to
increase the germination rate from 1.5% to 41.1% and the remaining rate from 1.7% to 44.2%. Forty crossing combinations were
conducted and 2 744 hybrid seedlings were obtained. MX4 × P. grandidentata (G-1-58), MX3 × P. tremuloidis (T-44-60), MX2 × P. tremuloidis (1-13-87-37) and MX2 × (P. alba × P. grandidentata) were regarded as superior combinations after analysis and selection. Thirty seedlings of these combinations and 11 triploid
seedlings identified by counting their chromosomes were selected as super plants.
[Supported by the Doctoral Foundation of Ministry of Education (Grant No. 200220022004) and the National “863” Project (Grant
No. 2002AA241071)] 相似文献
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The competition–density (C–D) effect for non-self-thinning Populus deltoides and Populus × euramericana plantations from 3 to 9 years was analyzed using the reciprocal equation of the C–D effect. The C–D effect was well described
by the reciprocal equation, and with the progress of time the C–D curve, on logarithmic coordinates, of the P. × euramericana plantations shifted upward faster than that of the P. deltoides plantations. With increasing physical time t, the biological time τ, i.e. the integral from zero to t of the coefficient of growth λ(t) in the general logistic curve with respect to t, increased rapidly during early growth stages and the increases in τ gradually became slow during later growth stages. This trend was more evident in the P. deltoides plantations than in the P. × euramericana plantations. The coefficients A and B included in the reciprocal equation were calculated at each growth stage. With increasing τ, the coefficient A, the reciprocal of which means the asymptote of yield (=wρ) at a given growth stage, increased abruptly to a maximum value and then tended to decrease gradually to a constant level.
On the other hand, the coefficient B, the reciprocal of which means the asymptote of mean stem volume at a given growth stage, decreased exponentially and tended
to be close to zero with increasing τ. The λ(t) decreased with increasing stand age, whereas the final yield Y(t) defined as W(t) ρ, where W(t) is the asymptote of w in the general logistic growth curve, increased gradually with increasing stand age. The differences in coefficients A, B, and λ(t) between the two species were reported. 相似文献
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Four Populus clones were grown for two years at 1×1 m spacing for study of total biomass production and carbon sequestration capacity
on floodplain sites previously in forage grasses under climatic conditions of the lower Midwest, U.S.A. Total biomass (above-and
below-ground) in the first year ranged from 3.9 Mg ha–1 in a Populus deltoides x P. nigra clone (I45/51) to 1.9 Mg ha–1 for a local-source Populus deltoides clone (2059). Second year total biomass production was substantially higher, ranging from 13.9 Mg ha–1 in I45/51 to 7.4 Mg ha–1 in P. deltoides clone 26C6R51. Second-year leaf area index (LAI) values for I45/51 plants reached 4 during mid-season, indicating essentially
complete canopy closure in this clone by the second year after planting. In contrast, maximum mid-season, second-year LAI
was significantly lower in P. deltoides clones ( 2.4). There was some evidence for differential allocation to roots and shoots among Populus clones, with 26C6R51 showing relatively more allocation to root biomass than other clones. Second-year growth in Populus deltoides clone 2059 accelerated substantially, and this genotype exhibited two-year biomass accumulation nearly equal to that of I45/51
despite having less leaf area. This result suggested a higher photosynthetic capacity or assimilation efficiency in the former.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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[目的]开展不同品系的杨树亲本来源、干部物理特性与抗性关系研究,为抗杨干象新品系的选育奠定一定基础.[方法]本研究连续2年研究了10个亲本51个不同杨树品系10~11年生杨树的被害株率、杨干象虫口密度与杨树木质部硬度、树皮硬度、树皮厚度、胸径等的关系.[结果]免疫品系、高抗虫品系、抗虫品系、感虫品系和高感虫品系木质部平均硬度分别为(47.38±1.71 ) HD、(46.07±1.17) HD、(44.64±1.61) HD、(41.84±1.66) HD、(40.73±2.04) HD;树皮平均硬度分别为(40±3.53) HD、(39.99±0.96) HD、(37.63±0.46) HD、(32.35±1.54) HD、(31.7±0.52) HD;平均胸径分别为(361.64±13.8) mm、(313.8±6.19) mm、(309.98±5.27) mm、(289.56±10.73) mm、(287.67±17.49) mm,亲本为美洲黑杨×青杨、马氏杨、美洲黑杨×马氏杨、小叶杨×胡杨的品系为抗虫品系;亲本欧洲黑杨×美洲黑杨、欧洲黑杨×小叶杨、美洲黑杨的多数品系为感虫品系.[结论]杨树木质部硬度与树皮硬度越大抗杨干象能力越强;胸径生长相对较快的品系抗性强;青杨、马氏杨、小叶杨为亲本抗虫性强,美洲黑杨、欧洲黑杨为亲本抗虫性差.在抗杨干象品系育种工作中应选择青杨、小青杨或甜杨做为亲本;避免以美洲黑杨或欧洲黑杨为亲本. 相似文献
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In order to discover which ectomycorrhizal-(ECM) fungi have better growth-promoting effects on poplars, cuttings from four
poplar species were inoculated with nine species of ECM fungi by three methods. We investigated the status of mycorrhizal
formation and the effects of these fungi on the growth of the poplars. The results show that Xrocomus chrysentero (Xc), Boletus edulis (Be), Pisolithus tinctorius (Pt) and Laccaria amethystea (La) formed clear ectomycorrhizal symbiosis with the poplar seedlings. Among these four ECM fungi, Xc had the greatest ability
to develop mycorrhizae with all four poplar species. Be shows a greater ability to form mycorrhizae with Populus deltoides Bartr cv. ‘Lux’ (Poplar I-69). Pt and La had relatively weaker abilities of colonization. The other five ECM fungal species,
i.e., Scleroderma luteus (Sl), Leccinum scabrum (Ls), Boletus speciosus (Bs), Calvatia craniiformis (Cc) and Rhizopogen luteous (Rl) could not easily form mycorrhizae with poplar seedlings grown in sterilized substrates, but could do so in non-sterilized
soil. With the method of drilling and injecting liquid inoculum, a simple operation, the mycorrhizal infection rates were
higher than with the other two methods, applying solid inoculum as fertilizer at the bottom of the pots and dipping roots
in the inoculum slurry. P. simonii Carr. formed mycorrhizae with most of the nine ECM fungi. P. x euramericana (Dode) Guinier cv. ’san Martino’ (Poplar I-72) and P. deltoids Harvard x P. deltoids Lux (Poplar NL-351) had the highest compatibility with Pt. Poplar I-69 shows the highest compatibility with Xc. The study
indicates that the optimal ECM fungi for poplars I-69, I-72 and NL-351 were Be, Xc and Pt, respectively. The optimal fungi
for P. simonii Carr. were Xc and Be. These ECM fungi promoted the growth of the poplar seedlings significantly.
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Translated from Journal of Nanjing Forestry University (Natural Sciences Edition), 2007, 31(6): 29–33 [译自: 南京林业大学学报(自然科学版)] 相似文献
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辽育3号杨等树种对水泡溃疡病抗性的试验研究 总被引：2，自引：0，他引：2
对辽宁杨、辽育3号杨、鞍山小钻杨3个品种进行了水泡溃疡病抗性试验,通过野外调查、室内接种、树皮含水率和愈伤组织形成4方面的测试,认为辽宁杨抗病性略优于辽育3号,二者基本处于同一水平,这2个品种抗病性都优于小钻杨,差异达到极显著水平。愈伤组织形成指数和1年生树皮含水率2个指标,都是辽宁杨>辽育3号杨>小钻杨。进一步分析表明,野外调查感病指数与室内接种感病指数、树皮含水率、愈伤组织形成指数呈现spearman相关性,达到极显著水平。其中野外调查感病指数与室内接种感病指数呈正相关,野外调查感病指数与树皮含水率、愈伤组织形成指数分别呈负相关。 相似文献