Validation of a small-area method for estimating the spatial distribution of the degree of tree damage     

Rafał Podlaski 《European Journal of Forest Research》2004,123(3):229-237

This article presents a validation of a method, proposed in Podlaski (2003), for estimating the degree of tree damage. This method belongs to a group of small-area methods. To estimate the degree of tree damage in individual P₃ sub-blocks of the SINUS system of information on the natural environment, a classification based on the degree of defoliation was used. Spatial distribution of the degree of tree damage was estimated through unrestricted simple random sampling. The maximum total estimation error for proportions of fir and beech with a damage degree of zero, and also with second and third degrees jointly, reached a maximum of 35.6% for fir, and 33.8% for beech. P₃ sub-blocks characterised by the highest proportion of the healthiest trees (at least 15% being undamaged trees) occurred in patches in the case of fir, and in larger, compact areas in the case of beech. Because spatial diversification in the health of fir, and to a smaller degree in the case of beech, occurs at small scales, small-area methods for estimating tree condition are necessary. An analogous scheme, combining small-area with large-area methods (utilising sub-blocks of the network of large-area systems in a small-area inventory, and establishing a common database), could be used on a wider scale; for example, by supplementing the program of estimating tree health carried out by the United Nations Economic Commission for Europe (Lorenz et al. 2002) with local inventories.  相似文献   

在低温锻炼中毛白杨幼苗可溶性总蛋白、RNA、DNA、RNase及抗冻性的变化   总被引：4，自引：0，他引：4  

林善枝  张志毅 《中国林学(英文版)》2002,4(2):9-15

低温锻炼不仅提高了毛白杨幼苗存活率和抗冻性以及RNA和可溶性总蛋白的含量 ,降低了RNase活性 ,而且能减轻低温胁迫引起的RNA和可溶性总蛋白含量的下降程度和RNase活性的提高 ,有利于幼苗在恢复过程中RNA和可溶性总蛋白水平的迅速回升以及RNase活性的降低 .进一步研究发现 ,DNA含量无论在低温锻炼中还是在低温胁迫下或是在随后的恢复生长期均保持相对稳定 ;低温锻炼所引起的RNA含量的增加 ,与RNase活性的降低呈明显的负相关 ,与可溶性总蛋白含量的增加以及幼苗抗冻性的提高成正相关 .这表明低温锻炼可能抑制RNase活性 ,有效地促进RNA含量的增加 ,而RNA可能参与了可溶性总蛋白的合成及抗冻性的诱导  相似文献   

福州地区人工杉木林分蓄积量表的研究     

兰名驹  王光玉 《福建林业科技》1994,21(1):62-66

本文提出以林分构成因子——林分胸高总断面积及林分平均高，估计林分蓄积量的办法，选取９种方程求解参数，配合了最优林分蓄积量经验方程，制定出《福州地区人工杉木林分蓄积量表》，对完善我省林业数表的种类、形式和内容，进行了初步尝试。  相似文献   

全站仪测算伐区设计蓄积的原理及其应用     

赖日文  陈平留 《中南林业科技大学学报(自然科学版)》2004,24(2):37-40

对全站仪测树原理进行了研究分析,应用全站仪与PC-E500袖珍计算机或PDA连接,可自动测算伐区或样地内每一株立木的树高、胸径或树干任意高度处直径,进而可自动而精准地计算出单木材积和伐区立木蓄积.理论上,树高的量测精度可达1/1 400.直径的量测精度可达1/200.实测结果表明:全站仪重复测量数据比较稳定,直径的量测误差在毫米级以内,树高的量测误差控制在厘米级,材积测定精度可优于1%,均高于测树的需要精度.全站仪测树技术实现了实时、快速、精准测定立木材积,不用材积表推求蓄积量,克服了传统测树方法的缺陷,其实测数据可作为伐区设计立木蓄积的测算依据.  相似文献   

浅谈如何用全站仪调查古树名木     

欧文琳 《山东林业科技》2007,(6):68-69,48

在传统调查方法中引入全站仪、GPS等精密仪器和交叉定年技术,对古树名木调查方法进行了改进。比较和探讨了两种调查方法,结果表明新的调查方法提高了树龄、树高、胸径和冠幅等关键数据的精度,并增加了地理坐标数据和多媒体信息的采集。  相似文献   

超临界CO2萃取测定食品中总脂肪的研究     

何钢  谢涛  谢碧霞 《经济林研究》2003,21(3):28-31

超临界CO2(S-CO2)萃取用于测定食品中的总脂肪含量，是一种很有前途的方法。文中具体介绍了测定总脂肪的S-CO2萃取法，并对其测定结果进行了统计分析，S-CO2萃取法用于全脂奶粉和营养奶粉总脂肪的测定，其浸提率分别为97．4％和98．4％。另外，S-CO2法萃取的总脂肪中主要脂肪酸种类及其含量与碱性乙醚萃取法相近。  相似文献   

连翘叶总黄酮提取工艺的研究     

张建红  黄亚亚  李发荣  杨建雄 《陕西林业科技》2005,(4):4-6

通过正交方法分析回流次数、乙醇浓度、回流时间、料液比对连翘叶总黄酮得率的影响。结果表明：连翘叶中总黄酮的最佳提取方案是：回流3次，料液比1：6，乙醇浓度55％，每次回流时间60min。总黄酮的得率为10．79％，回收率为104％，RSD=0．75（n=3）。  相似文献   

浅谈当前森林覆盖率计算的两个公式   总被引：1，自引：0，他引：1  

李炳凯 《林业调查规划》2007,32(4):8-10

介绍计算森林覆盖率的2个公式,指出应该用(2)式计算森林覆盖率.分析了有林地面积、国家特别规定灌木林地面积、灌木林地面积与森林覆盖率的关系.  相似文献   

贺兰山西坡不同海拔梯度草地土壤磷特征及其影响因素   总被引：1，自引：0，他引：1  

宋雄儒  尚振艳  李旭东  傅华 《草业科学》2015,(7):1054-1060

对贺兰山西坡不同海拔的不同类型草地土壤磷素的空间分布特征以及环境及植被因素对土壤磷素的影响进行了研究。结果表明,0-10和10-20cm土层土壤全磷(TP)含量随着海拔由高到低而显著降低;两土层中,土壤全磷与土壤有机碳、土壤中0.05mm粘粉粒含量及植被盖度之间呈显著正相关(P0.05),土壤全磷沿土壤剖面的垂直分布没有一致规律性;土壤速效磷含量随着海拔高度和草地类型的变化没有呈现出一定的变化规律,两土层中土壤速效磷/全磷比值(AP/TP)与土壤pH值以及年平均气温呈显著正相关(P0.05),说明该区土壤pH值和温度的变化能显著影响土壤磷的活化;多数样地0-10cm土层速效磷显著高于10-20cm土层,可能归因于植物对磷素的表聚作用。  相似文献   

Effects of utilization of local food by‐products as total mixed ration silage materials on fermentation quality and intake,digestibility, rumen condition and nitrogen availability in sheep          下载免费PDF全文

Srita Yani  Kyohei Ishida  Shuzo Goda  Shigeyoshi Azumai  Tomoyuki Murakami  Masayuki Kitagawa  Kanji Okano  Kazato Oishi  Hiroyuki Hirooka  Hajime Kumagai 《Animal Science Journal》2015,86(2):174-180

Four wethers were used in a 4 × 4 Latin square design experiment to evaluate in vivo digestibility of total mixed ration (TMR) silage with food by‐products for dairy cows, and the ruminal condition and nitrogen (N) balance were examined. Five by‐products (i.e. potato waste, noodle waste, soybean curd residue, soy sauce cake and green tea waste) were obtained. Four types of TMR silage were used: control (C) containing roughage and commercial concentrate, T1:20% and T1:40% containing the five by‐products replacing 20% and 40% of the commercial concentrate on a dry matter (DM) basis, respectively, and T2:40% containing three by‐products (potato waste, noodle waste and soybean curd residue) replacing 40% of the commercial concentrate on a DM basis. The ingredients were mixed and preserved in oil drum silos for 4 months. The TMR silages showed 4.02–4.44% and 1.75–2.19% for pH and lactic acid contents, respectively. The digestibility of DM and neutral detergent fiber, and total digestible nutrient content were higher (P < 0.05) for T2:40% feeding than for C feeding. Urinary nitrogen excretion tended to be lower (P = 0.07) for T2:40% than for C. The results suggested 40% replacing of commercial concentrate by using the three food by‐products can be most suitable for TMR silage.  相似文献