基于朴素贝叶斯分类器的棉花盲椿象危害等级识别

针对自然条件下棉花盲椿象危害区域提取和危害等级识别难的问题,提出了棉花盲椿象危害等级自动识别方法。该方法以自然条件下采集的不同盲椿象危害等级棉叶图像为对象,利用最大类间方差阈值分割和多颜色分量组合方法进行作物与土壤分离和病斑分割,并利用分水岭分割方法对粘连棉叶进行分离并提取盲椿象危害棉叶区域,提取图像的颜色、纹理和形状特征,结合朴素贝叶斯分类器,依据划分的棉花盲椿象危害等级标准,对盲椿象危害等级进行识别。不同盲椿象危害等级识别试验结果表明:该模型平均识别正确率达90.0%,通过比较试验表明,该模型在识别精度比BP神经网络高2.5%,运行速度比支持向量机高11.7%,可较好的对棉花盲椿象危害等级进行识别,可为棉花盲椿象的防治提供技术支持。     

连云港花果山高分辨率森林火险等级三维可视化短期预报研究

以连云港花果山为研究区,将火险等级预报因子归纳为森林火险区划、天气、火源等3个类别。其中火险区划根据植被类型、植被特征、地形因子获取;天气因子通过24h天气预报获取;火源危险等级由景区内的道路进行缓冲区分析获取。利用3类火险因子,通过加权叠置法建立火险等级短期预报模型,进行火险等级预报;利用DEM和SPOT5影像,通过GIS三维可视化技术,对预报结果进行三维可视化显示。通过研究实现了火险等级短期预报,将火险等级落实到小班,并将火险等级分布信息以三维可视化方式显示,为研究区森林火险实时监测提供了基础平台,为山区林火科学化管理提供技术支持。     

PHENIPS—A comprehensive phenology model of Ips typographus (L.) (Col., Scolytinae) as a tool for hazard rating of bark beetle infestation

We developed the model PHENIPS for spatial and temporal simulation of the seasonal development of Ips typographus at the Kalkalpen National Park in Austria. The model is based on a digital elevation model used for interpolation of temperature and solar radiation to calculate the microclimatic conditions (bark temperature) for the beetles’ development. Additionally, the beetles’ phenology at Kalkalpen National Park was monitored along with air and bark temperature measurements. The onset of host tree infestation in spring was estimated using a lower threshold of 16.5 °C for flight activity and a mean thermal sum of 140 degree-days (dd) from beginning of April 1st onward. Rate of brood development was calculated from accumulated degree-days of hourly temperature data using upper and lower temperature thresholds of 38.9 and 8.3 °C, respectively, and a nonlinear function for calculating effective thermal sums. Re-emergence of parental beetles occurred at a time when 49.7% of the thermal sum for total development (557 dd) was reached. The model includes the discontinuance of the beetle's reproductive activity at a day length <14.5 h. The rate of successful hibernation of established broods is predicted by assessing the developmental stage of initiated generations at the beginning of the cold period. For validation we compared the timing of phenological events in the field with predicted events using both, hourly recorded data at trap trees in the terrain and generated daily topoclimatic data. Using topoclimatic data, the onset of infestation was predicted with a mean absolute error of 1.3 days. The observed onset of emergence of filial beetles in the field was estimated with a mean error of 39 dd. Our PHENIPS explicitly considers the strong effects of regional topography and stand conditions on local air and bark temperature and can be used for precise monitoring of the actual state of bark beetle development at the specific stand/tree level. Using topoclimatic data, PHENIPS simulates the maximum number of generations which is necessary to assess the potential impact of bark beetle outbreaks at regional scale. Further applications of PHENIPS for site-specific hazard rating of bark beetle infestation are discussed.     

Defect-disorder and risk assessment of heritage trees in urban Hong Kong

Heritage trees in a city, echoing factors conducive to outstanding performance, deserve special care and conservation. To understand their structural and health conditions in urban Hong Kong, 30 defect-disorder (DD) symptoms (physical and physiological) subsumed under four tree-position groups (soil-root, trunk, branching, and crown-foliage) and tree hazard rating were evaluated. The surveyed 352 trees included 70 species; 14 species with 233 trees were native. More trees had medium height (10–15 m), medium DBH (1–1.5 m) and large crown (>15 m). In ten habitats, public park and garden (PPG) accommodated the most trees, and roadside traffic island (RTI) and public housing estate (PH) had the least. Tree dimensions and tree habitats were significantly associated. The associations between the 2831 DD and tree-position groups, tree habitats and tree hazard rating were analyzed. Fourteen trees from Ficus microcarpa, Ficus virens and Gleditsia fera had high hazard rating, 179 trees from 22 species moderate rating, and 159 trees from 55 species low rating. RTI, roadside tree strip (RTS), roadside tree pit (RTP), roadside planter (RP) and stone wall (SW) had more moderate hazard rating, and PPG, roadside slope (RS) and government, institutional and community land (GIC) more low rating. Redundancy analysis showed that DD were positively correlated with RTS, RTP, RP and SW, but negatively correlated with PPG, RS and GIC (p < 0.05). The DD significantly increased tree hazard rating and failure potential. Future management implications for heritage-tree conservation and enhancement focusing squarely on critical tree defect-disorder in urban Hong Kong were explored, with application to other compact cities.     

凉山亚热带区紫花苜蓿引种筛选试验

2005-2006年通过对11个不同秋眠级紫花苜蓿Medicago sativa品种的生长特性及生产性能等方面的观察测定,结果表明,不同秋眠级品种在凉山亚热带地区能顺利越冬越夏,3-5月能顺利开花结实,种子成熟率高;其生长速度和产草量均是非秋眠级＞半秋眠级＞低秋眠级,主要差异表现在秋冬季,再生速度和生物量差异极显著(P＜0.01).在凉山亚热带地区宜种植非秋眠性的苜蓿品种(如四季绿、WL414、盛世)及部分适应性好、产量高的半秋眠级品种(如威可),低秋眠级品种在该地高海拔区的适应性有待进一步研究.     

建水县林地保护利用规划探究

介绍建水县林地资源特点,分析林地保护利用潜力及存在的问题。基于林地保护等级划分、占用征用林地规模控制和林地使用方向控制对建水县林地保护进行规划;基于林地功能分区、山地城镇建设和林地质量评级进行林地利用规划。并对林地保护利用的风险进行分析。提出合理配置林地资源,提高林地利用效益,强化林地征占用管理等保障措施。     

中国肉用西门塔尔牛场间遗传联系分析

旨在加快中国肉用西门塔尔牛的遗传进展,实现全国范围内的联合育种。本研究利用全国38家育种场和公牛站在2000—2019年出生的3 991头肉用西门塔尔牛初生重性状,使用DMU软件对场间关联率进行计算。对各场站划分关联组,并比较单场和关联组内的遗传力和估计育种值（estimated breeding value,EBV）的预测准确性。结果表明,中国肉用西门塔尔牛全国平均关联率为1.91%,大部分场间关联率处于较低水平。依据关联率可划分出两个关联组,分别包括6个和8个场,组内平均关联率分别为11.23%和12.54%。对两个关联组分别进行单场和联合估计,单场估计初生重的遗传力范围为0.32~0.44,关联组1的初生重遗传力为0.47,关联组2的初生重遗传力为0.43。两个关联组单场估计EBV的平均准确性分别为0.47和0.45,联合估计EBV的平均准确性分别为0.61和0.56。联合估计较单场估计EBV的准确性有明显提高。依据关联率划分关联组进行联合育种有利于加快中国肉用西门塔尔牛的育种进程。为推进中国肉用西门塔尔牛的育种进程,应先形成区域性联合育种,再逐步加强遗传联系,形成全国范围内的遗传关联体系。     

Fire models and methods to map fuel types: The role of remote sensing

Understanding fire is essential to improving forest management strategies. More specifically, an accurate knowledge of the spatial distribution of fuels is critical when analyzing, modelling and predicting fire behaviour. First, we review the main concepts and terminology associated with forest fuels and a number of fuel type classifications. Second, we summarize the main techniques employed to map fuel types starting with the most traditional approaches, such as field work, aerial photo interpretation or ecological modelling. We pay special attention to more contemporary techniques, which involve the use of remote sensing systems. In general, remote sensing systems are low-priced, can be regularly updated and are less time-consuming than traditional methods, but they are still facing important limitations. Recent work has shown that the integration of different sources of information and methods in a complementary way helps to overcome most of these limitations. Further research is encouraged to develop novel and enhanced remote sensing techniques.     

进境水果安全风险分级评价及管理措施研究

面向口岸一线进境水果监管工作的实际需求,针对进境水果“事前”主要风险要素开展风险评估。通过建立半定量的评估方法,将口岸截获等反馈数据与专家评判相结合,以二维矩阵确定进境水果检验检疫风险因子评价等级,最终划分进境水果风险等级,提出相应风险分级管理措施。其主要目的在于实现进境水果“事中”查验环节在有效防控风险的前提下重点突出、提升效率,进而压缩通关时长。