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91.
The abundance, structure, and distribution of oribatid communities in high-mountain pine forest biotopes of the Eastern Caucasus are described in dependence on elevation above sea level. The oribatid fauna of high-mountain pine forests proved to be characterized by high abundance, an assortment of dominants, and species richness. It was shown that, as the elevation increases, specific dominants typical of particular altitudinal zones appear in communities, and changes in the mass species occur. These species are stable in terms of their long-term dynamics, and zonal groups (communities) demonstrate a high species diversity.  相似文献   
92.
Nei's genetic distances (Nei, 1972, 1978) between 12 Scotch pine (Pinus sylvestris L.) populations were determined using isozyme analysis. The gradients of these distances along the 1500-km meridional transect in the Transural Region and Northern Turgai from the pre-forest-tundra subzone (the Synya River basin) to the southern steppe (the Naurzumskii forest) were calculated. We discovered that the genetic distance gradients (GDGs) progressively increase in the direction from the northern boundary of the range to the southern boundary of the forest-steppe zone and sharply increase in the insular forests growing in the steppe zone. The results of cluster analysis and Mahalanobis distance gradients with respect to a set of morphological characters of the cones provide evidence that Scotch pine populations of the forest zone share somewhat the same gene pool, whereas the group of Scotch pine populations in the insular forests of Northern Turgai is obviously differentiated phenogenetically from the insular forests of the Tobol region, which grow farther to the north.  相似文献   
93.
The aim of this work was to test a process-based model (hydrological model combined with forest growth model) on the simulation of seasonal variability of evapotranspiration (ET) in an even-aged boreal Scots pine (Pinus sylvestris L.) stand over a 10 year period (1999-2008). The water flux components (including canopy transpiration (Et) and evaporation from canopy (Ec) and ground surface (Eg) were estimated in order to output the long-term stand water budget considering the interaction between climate variations and stand development. For validation, half-hourly data on eddy water vapor fluxes were measured during the 10 growing seasons (May-September). The model predicted well the seasonal course of ET compared to the measured values, but slightly underestimated the water fluxes both in non-drought and drought (2000, 2003 and 2006) years. The prediction accuracy was, on average, higher in drought years. The simulated ET over the 10 years explained, on average, 58% of the daily variations and 84% of the monthly amount of ET. Water amount from Et contributed most to the ET, with the fractions of Et, Ec and Eg being, on average, 67, 11 and 23% over the 10-year period, respectively. Regardless of weather conditions, the daily ET was strongly dependent on air temperature (Ta) and vapor pressure deficit (Da), but less dependent on soil moisture (Ws). On cloudy and rainy days, there was a non-linear relationship between the ET and solar radiation (Ro). During drought years, the model predicted lower daily canopy stomatal conductance (gcs) compared with non-drought years, leading to a lower level of Et. The modeled daily gcs responded well to Da and Ws. In the model simulation, the annual LAI increased by 35% between 1999 and 2008. The ratio of Ec: ET correlated strongly with LAI. Furthermore, LAI reduced the proportion of Eg as a result of the increased share of Ec and Et and radiation interception. Although the increase of LAI affected positively Et, the contribution of Et in ET was not significantly correlated with LAI. To conclude, although the model predicted reasonably well the seasonal course of ET, the calculation time steps of different processes in the model should be homogenized in the future to increase the prediction accuracy.  相似文献   
94.
鞘翅目昆虫多样性的变化是森林演替过程的综合反映.于2007年6~8月采用陷阱诱捕法对长白山阔叶红松林带不同演替阶段地表甲虫物种组成和数量进行了调查,并分析了该地区不同演替阶段地表甲虫多样性的变化趋势及主要生境因子对地表甲虫群落的影响.结果显示,长白山阔叶红松林内共诱捕地表甲虫23种,共511头,隶属于10个科.其中个体数最多的为埋葬甲科,物种数最多的为步甲科,优势类群为步甲科和埋葬甲科.不同演替阶段中,次生白桦林地表甲虫物种数和个体数高于原始阔叶红松林和次生针阔混交林,3个生境内地表甲虫多样性无显著差别.地表甲虫高峰期为7月份.不同演替阶段的样地中物种统计数量都没有达到渐进线,次生白桦林样地中实际物种只占估计值的67%,其它2个生境实际物种数都在物种估计值的95%区间范围内,略低于平均值.3个生境的地表甲虫种-多度曲线无显著差异,符合对数分布.胸高断面积和土壤湿度对地表甲虫的分布有显著影响,它们可以解释99.2%的物种与环境之间的关系.  相似文献   
95.
Throughfall and open field bulk precipitation were measured at three coniferous sites during 1995–2002 in the framework of ICP Integrated Monitoring and at five coniferous sites during 1996–2002 in the framework of ICP Forests (Level II). The coniferous canopies acted as a sink for nitrate and ammonium and as a source for base cations: Ca2+, Mg2+ and K+. The estimated share of SO4–S dry deposition from total deposition was 1.5–4 times higher for dormant period compared to growing period. During the study period average annual throughfall and bulk deposition of SO4–S decreased significantly, 2.8 and 2.3 times, respectively. Throughfall enrichment with base cations increased in the order Mg < Na < Ca < K. Using Na as a tracer ion, average dry deposition and canopy leaching were calculated. Leaching was the dominant process for TF enrichment by potassium. Leaching of base cations occurred during growing as well as dormant period. The calculated internal flux of Ca2+ and Mg2+ varied in the range of 0.6–2.0 and 0.6–1.2 kg ha−1 per year in spruce and pine stands, respectively. The internal circulation of K+ was significantly higher (8.9–10.9 kg ha−1 per year) in spruce stands than in pine stands (2.7–4.4 kg ha−1 per year).  相似文献   
96.
在氮气氛围下热解制备松针炭,采用浸渍法将硝酸铈负载到松针炭上,在300℃氛围中焙烧2 h,制得铈改性松针炭。用罗丹明B溶液模拟染料废水,分别研究松针炭和铈改性松针炭对罗丹明B的吸附效果。实验表明:加热温度为300℃、升温速率为10℃/min、加热时间为2 h时,制备的松针炭对罗丹明B的去除率为68.8%;浸渍浓度为0.02 mol/L、焙烧温度为300℃时制备的Ce/PC复合材料对罗丹明B的去除率为81.6%。松针炭经铈改性后,吸附性能大幅提高。  相似文献   
97.
The ability of pine bark and almond shells to remove bisphenol A (BPA) from aqueous solutions was evaluated. Samples of these traditional agro-forestry by-products were milled, sieved into different particle size fractions (0.10–0.15 and 1.5–2.0 mm) and submitted to two different types of treatment. Sorption experiments were conducted in a batch system at room temperature and natural pH. Sorption equilibrium was attained after 48 h for all systems under study. Bisphenol A was adsorbed more effectively on the smaller particles of the sorbents. Pine bark and almond shell pretreated with formaldehyde presented higher sorption efficiency (95%), followed by almond shell (87%) and pine bark (82%) washed with hot water. All the sorption isotherms were found to fit a Freundlich equation, with correlation coefficients (R 2) between 0.823 and 0.989. The sorption coefficient (K F) ranged from 0.06 to 0.74 (mg1?1/n ·L 1/n ·g ?1). These results indicate that utilisation of both materials as an alternative sorbent for the removal of bisphenol A from contaminated waters is promising because they are available in large amounts and have an acceptable cost–efficiency ratio when compared with traditional adsorbents.  相似文献   
98.
The various indigenous uses and structure of chir pine forests were studied in Uttaranchal state of the Indian Republic. A questionnaire survey was conducted in 50 villages of Uttaranchal to gather information on the indigenous uses of chir pine. For the study of community composition and structure of chir pine forest, at least 15 quadrats of 10 x 10 m were selected randomly across various localities, and the number of individuals, along with other dominant tree and shrub species, were enumerated in each quadrat. About 10 indigenous uses of chir pine were prominent in Uttaranchal. Besides resin, an important non-wood product, different parts of chir pine, such as cones, trunk, stems, wood, leaves and bark, were used by the local people. Chir pine is a subject of the folklore and mythology of indigenous cultures in Uttaranchal. Chir pine forest formed three major communities in Uttaranchal viz., sal-pine (Shorea robusta-Pinus roxburghii), pine pure stands and oak-pine (Quercus leucho-trichophora-Pinus roxburghii). These communities sustained various multiple-use trees and shrubs along with various edible mushrooms (eg. Agaricus campestris, Morchella esculenta and Sparassis crispa). The results of this study are discussed in the light of chir pine conservation and management policies.  相似文献   
99.
ABSTRACT: Sulfometuron methyl [methyl 2-[[[[4,6-dimethly 2-(pyrimidinyl) a-mino] carbony l]amino] sulfonyl] benzoate] was applied by a ground sprayer at a maximum labeled rate of 0.42 kg ha-1 a.i. to a 4 ha Coastal Plain flatwoods watershed as site preparation for tree planting. Herbicide residues were detected in Streamflow for only seven days after treatment and did not exceed 7 mg m-3. Sulfometuron methyl was not detected in any stormflow and was not found in any sediment (both bedload and suspended). Sampling of a shallow ground water aquifer, > 1.5 m below ground surface, did not detect any sulfometuron methyl residues for 203 days after herbicide application. Lack of herbicide residue movement was attributed to low application rates, rapid hydrolysis in acidic soils and water and dilution in streamflow.  相似文献   
100.
The Jack Creek watershed, a 133 km2 (51.5 mi2) drainage in southwestern Montana, was impacted by a mountain pine beetle (Dendroctonus ponderosae Hopkins) epidemic in 1975–1977 which killed an estimated 35 percent of its total timber. Analyses of USGS streamflow data for four years prior to and five years after mortality suggest a 15 percent post-epidemic increase in annual water yield, a two-to three-week advance in the annual hydrograph, a 10 percent increase in low flows and little increase of peak runoff.  相似文献   
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