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31.
湿地松是宁都县第二大人工栽植优势树种,笔者通过近3a的实践和走访,探讨湿地松高产栽培和抚育管护技术及防灾措施.  相似文献   
32.
热处理对马尾松蓝变材颜色的影响   总被引:1,自引:0,他引:1  
热处理选取了5个温度(170、185、200、215、230℃)和4个时间(2、4、6、8 h)。在热处理前后分别测量蓝变点与未蓝变点的颜色,分析了蓝变材颜色的均匀性,对比了蓝变点与未蓝变点的颜色差异和变化规律。实验结果表明:热处理后,蓝变材颜色参数的标准差逐渐降低,蓝变点与未蓝变点明度差、黄蓝色品指数差减小,其色差可以从17.57降低到小于1。均值比较结果显示,经过200℃以下的热处理,蓝变点与未蓝变点间的颜色参数仍然具有显著性差异。为了使蓝变色斑达到肉眼不容易识别的程度,最低的热处理条件为200℃下处理6 h。  相似文献   
33.
In Poland's pine forests, mistletoe (Viscum album subsp. austriacum) abundance has increased over the past 20 years. This mistletoe infestation has decreased the growth and vigour of Scots pine trees. In this study, we surveyed the culturable fungi from healthy and diseased V. album subsp. austriacum leaves from two stands in Poland. In total, 63 distinct species were identified, 99.8% of which belonged to the phylum Ascomycota. The community compositions of fungi in mistletoe leaves were similar in healthy and diseased leaves as Alternaria alternata, Aureobasidium pullulans, Botryosphaeria visci, Fusarium paeoniae and Microsphaeropsis olivacea were consistently found in leaves of all symptom types. The most frequently isolated fungus from asymptomatic leaves was M. olivacea, followed by A. alternata, A. pullulans and Hypoxylon rubiginosum. In comparison, the most frequently isolated fungi from leaves with rusty-brown necrotic spots were (in decreasing order) M. olivacea, B. visci, F. paeoniae and A. alternata, while the most frequently isolated fungi from leaves with black or dark brown spots were M. olivacea, A. alternata, A. pullulans, Epicoccum layuense and F. paeoniae. This study was the first comprehensive report showing that certain fungal species may be pathogens of V. album subsp. austriacum in Poland. This study was also the first report of F. paeoniae, F. juglandicola, Diaporthe vacuae and Heterotruncatella spartii from V. album, and the first report of D. vacuae and H. spartii in Poland.  相似文献   
34.
棘胫小囊树皮甲虫(Coleopterla:Scolytidae)是一种与树木或新鲜木材兰染真菌相关的昆虫。本研究用不同种的松树制备的圆木诱捕、采集棘胫小囊树皮甲虫,并对其种类进行了比较。自4月至7月,从Pinus.rigida和Pinus.korniensis诱捕圆木上收集昆虫,共获得了10种树皮甲虫,其中Hylurgops interstitialis是P.koraiensi上最常见的甲虫,而Tomicus piniperda则在P.rigida上最常见。5月是H.interstitialis出现的高峰期,T.piniperda出现的高峰期是在4月。在6月上旬,新的成虫自蛹中孵化而出。为了研究树皮甲虫的种群与树木兰染真菌分离获得的频率的相关性,采用选择性培养基自成虫、卵/幼虫和树皮甲虫的虫道分离真菌。研究发现在越冬成虫和虫道上兰染真菌出现的频率分别是100%和94%,但在孵化的卵或刚孵出的幼虫上出现的频率相对较低。从兰染真菌分离出现的频率上看,收集的时间与树皮甲虫的种群没有显著的相关性。于4月20日可以首次观察到在虫道的下面出现变色现象,2周内,木材变色迅速增长,100%变色。对这些分离获得真菌进行鉴定,发现Leptographium spp出现频率高于Ophiostoma spp.。  相似文献   
35.
不同产地红松苗期生长的初步研究   总被引:1,自引:0,他引:1  
为探讨不同种源在辽东山区的生长表现,对17个产地红松子代在辽宁省草河口镇的苗期生长性状进行调查分析,结果表明,红松苗高和地径的生长在产地间的差异达到极显著水平,辽宁地区种源普遍优于吉林、黑龙江地区种源;红松苗期生长性状的基本变异模式是海拔垂直梯度为主,纬向渐变为辅的连续型变异。  相似文献   
36.
马尾松不同抚育方式对林地生产的影响   总被引:1,自引:0,他引:1  
对马尾松幼林采用全面劈草、全面劈草局部松土、全面除草松土3种抚育方式对林地植被生长、表层土壤变化及幼林生长的影响进行研究,结果表明:植被覆盖率、植被枯落物随抚育强度提高而降低,而土壤侵蚀则随抚育强度提高而增强,马尾松幼林生长与抚育强度提高成正比.在南方马尾松集约经营的山区,宜提倡带状抚育,既可促进幼林生长,又能维护地力.  相似文献   
37.
重庆市石宝镇马尾松单木生长模型研究   总被引:1,自引:0,他引:1  
为了更加科学地保护和利用马尾松森林资源并为其可持续经营提供参考依据,利用多模型选优法对重庆市忠县石宝镇马尾松的单木胸径生长模型进行了探讨与分析,结果表明:对竞争优势木和竞争劣势木的拟合效果最好的均是Richards函数,其次是Schumacher函数,而Gauss函数和Logistic函数的拟合效果较差.考虑到模型运算的简便性和结构的清晰性,结合研究区马尾松胸径生长量的预测情况,选取了模型参数相对较少的Schumacher 函数作为描述重庆市忠县石宝镇马尾松生长过程的最佳模型.  相似文献   
38.
Cortical oleoresins were obtained from 10 natural populations of Pinus sylvestris L. from different geographical localities. Gas chromatography was used to determine quantities of individual monoterpenes. Considerable variation was found in monoterpene composition among different populations. High proportions of limonene occurred in greater percentages in trees of northern origins, while high sabinene was frequently found in southern trees. Mean proportions of limonene and sabinene in the populations were clinal with latitude. For some monoterpenes, variation coefficients as a measure of variability within populations appeared to be clinal with latitude. 85.4% of the variance in monoterpene composition was found within populations and 14.6 between populations. Discriminant analysis differentiates populations from different geographical localities into different groups. The differences in monoterpene patterns between adjacent populations were statistically nonsignificant. It is recommended that monoterpene composition be used for more general study of genetic variation, geographical distinction between different populations and seed certification purposes.  相似文献   
39.
樟子松温室容器育苗出苗率达95%以上,表现为生长快,造林成活率高,通过温室容器育苗缩短育苗周期,经济效益显著。  相似文献   
40.

The effect of site fertility, spacing and mode of regeneration on the survival and stand development of lodgepole pine, Scots pine and Norway spruce was studied in a series of experiments comprising 22 study areas in Finland. After 13-14 yrs, lodgepole pine had a mean survival of 68% in planted and 61% in seeded plots, while Norway spruce had the highest (92%) and Scots pine the second highest survival (82%). The survival of planted lodgepole pine was better the wider the spacing. Best survival was achieved on subdry and dry sites, both with planting and with direct seeding. Dominant height was not affected by spacing, but both basal area and volume at the age of 13-14 yrs were significantly higher the denser the spacing. The average difference in the value of the estimated site index H 50 was slightly under 3 m for the superiority of lodgepole compared with Scots pine. Seeding resulted in site indices almost as high as those of lodgepole planting.  相似文献   
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