基于市场化城郊森林公园建设的思考

从调查太原西山城郊森林公园建设现状着手,深入分析了市场化机制下城郊森林公园建设所产生的问题,并提出了统筹规划、存同求异、整合联动等建设对策,以期为我国城郊森林公园的建设提供参考。     

A temporal analysis of urban forest carbon storage using remote sensing

Quantifying the carbon storage, distribution, and change of urban trees is vital to understanding the role of vegetation in the urban environment. At present, this is mostly achieved through ground study. This paper presents a method based on the satellite image time series, which can save time and money and greatly speed the process of urban forest carbon storage mapping, and possibly of regional forest mapping. Satellite imagery collected in different decades was used to develop a regression equation to predict the urban forest carbon storage from the Normalized Difference Vegetation Index (NDVI) computed from a time sequence (1985-1999) of Landsat image data. This regression was developed from the 1999 field-based model estimates of carbon storage in Syracuse, NY. The total carbon storage estimates based on the NDVI data agree closely with the field-based model estimates. Changes in total carbon storage by trees in Syracuse were estimated using the image data from 1985, 1992, and 1999. Radiometric correction was accomplished by normalizing the imagery to the 1999 image data. After the radiometric image correction, the carbon storage by urban trees in Syracuse was estimated to be 146,800 tons, 149,430 tons, and 148,660 tons of carbon for 1985, 1992, and 1999, respectively. The results demonstrate the rapid and cost-effective capability of remote sensing-based quantitative change detection in monitoring the carbon storage change and the impact of urban forest management over wide areas.     

天然林保护和林业分类经营的理论基础与问题

系统论述了天然林保护，林中分类经营的理论基础及分析了当前林业发展中的几个重大问题。     

Mapping insect defoliation in Scots pine with MODIS time-series data

Insect damage is a general problem that disturbs the growth of forests, causing economic losses and affecting carbon sequestration. Coarse-resolution data from satellites are potentially useful for national and regional mapping of forest damage, but the accuracy of these methods has not been fully examined. In this study, a method was tested for the mapping of defoliation in Scots pine [Pinus silvestris] forests in southeast Norway caused by the pine sawfly [Neodiprion sertifer], with the use of multi-temporal MODIS 16-day composite vegetation index data and the TIMESAT processing method. The damage mapping method used differences in summer mean values and angles of the seasonal profiles, indicating decreasing foliage density, to identify pixels that represent areas containing forest damage. In addition to 16-day NDVI the Wide Dynamic Range Vegetation Index (WDRVI) was tested. Damage areas were identified by classifying data into pixels representing damaged versus undamaged forest areas using a boolean combination of thresholded parameters. Classification results were evaluated against the change in LAI estimated from airplane LIDAR measurements, as an indicator of defoliation. The damage classifications detected 71% to 82% of the pixels with damage, and had kappa coefficients varying between 0.48 and 0.63, indicating some overestimation. This was due e.g. to failure to include clear-cut areas in the evaluation data. Damage classification with WDRVI only resulted in slight improvement compared to the NDVI. Only weak relationships were found between the LIDAR-estimated defoliation and the change parameters obtained from MODIS. Consequently, mapping of the degree of defoliation from MODIS was abandoned. In conclusion, the damage detection method based on MODIS data was found to be useful for locating insect damage, but not for estimating its intensity. Control of the detected damage areas using high-resolution remote sensing data, aerial survey, or fieldwork is recommended for accurate delineation in operational applications.     

A multi‐tracers analysis of sources and transfers of particulate organic matter in a tropical reservoir (Petit Saut,French Guiana)

We measured the organic carbon (OC) content, the isotopic composition, the C/N ratios and the photosynthetic pigment composition of suspended matter, sediments, sediments traps and epiphytic and epilithic biofilms at the tropical Sinnamary River system (French Guiana). Our sampling included the mid‐stream reservoir lake (Petit Saut) and the estuary on the Atlantic coast. These tracers were complementary and allowed identifying different sources of particulate organic matter (POM) in the system. We found a δ¹³C–C/N signature of POM close to that of soils and litters collected in the surrounding forest, both for water column and sediment at the upstream station as well as for the sediment in a littoral zone of the reservoir, which thus indicated a terrestrial origin. Plankton communities at the centre of the reservoir were dominated by Chlorophyceae (chlorophyll a (Chl a), chlorophyll b (Chl b) and lutein) in the oxic epilimnion and by anoxygenic phototrophic bacteria, namely Chlorobiaceae (bacteriochlorophyll d (BChl d) and bacteriochlorophyll c (BChl c)) at and below the oxycline (6 m depth). In addition, this planktonic material was slightly ¹³C‐depleted due to a contribution of methanotrophic bacteria. Phytoplankton and bacterioplankton were the major source of settling material collected in the traps at all depths in the centre of the reservoir. In the traps, POM was subject to intense degradation, as revealed by C/N and isotopic data and by the presence of pheopigments. In the river downstream of the dam, Chl b, lutein, BChl c and d originating from the reservoir progressively decreased downstream as the result of mineralization. At the estuarine mouth, fucoxanthin showed the presence of diatoms and the δ¹³C‐C/N signature matched that of POM carried by the Amazonian coastal mobile mud belt. By analysing sedimentation rates in the reservoir and its outflow into the river, we were able to provide a first estimates of POM transfers in this system during the sampling period. Copyright © 2008 John Wiley & Sons, Ltd.     

Seasonal and spatial variations and the effects of clear-cutting in the methane absorption rates of a temperate forest soil

Methane absorption rates of soils in a deciduous broad-leaf secondaryforest dominated by Quercus serrata in central Japan were measured by closed chamber technique from July 1995 to March 1999, focusing on its seasonal and spatial variations and the effects of clear-cutting. The measurement indicated that the methane absorption rate was the highest from late summer to beginning of autumn. The maximum value of the mean absorption rate was about 0.1 CH₄ m⁻²hr⁻¹. Regarding the spatial variation of the absorption rate, it varied along the position in a slope: the rate was higher at the lower position in a slope and lower at the upper position. After clear-cutting in the one of two adjacent watersheds constituting the study site, the highest mean absorption rate decreased to about 60–70 % of the last year's rate; our observations suggest that partial disturbance and erosion of the surface soil was the main reasons for the decrease. This revised version was published online in June 2006 with corrections to the Cover Date.     

Inverse Finite Element Analysis of Technological Processes of Heat and Mass Transport in Agricultural and Forest Products

Due to complexity of agricultural and forest products, the mathematical model coefficients are often dubious, as experimental determination of their values leads to erroneous results. To solve this problem an inverse finite element analysis software was developed to identify coefficient values of the heat and mass transport model and to predict and visualize the processes. The model reflected 3D structure of investigated systems comprising the heat conduction and moisture diffusion in heterogeneous, anisotropic, and irregularly shaped products represented by wood and cereal grain kernels. Test cases used to validate the software covered identification of the thermal conductivity, convective heat transfer coefficient, diffusion coefficient, equilibrium moisture content, and convective mass transfer coefficient in pine and beech wood, and also in corn. Implementation of the proposed optimization algorithm and improvement of the software functionality resulted in more effective and accurate identification of the coefficient values, demonstrated by increased accuracy and reliability of predicting the heat conduction and water diffusion processes.     

Seasonal change in nagilactone contents in leaves inPodocarpus nagi forest

Nagilactones isolated fromPodocarpus nagi (Thunb.) Zoll. et Moritz. are known by their physiological activities as a plant growth inhibitor or antiherbivory substance. As the first step in clarifying the nagilactone dynamics in a forest canopy, the seasonal variations in nagilactone contents in leaves and mass of nagilactones accumulated in the canopy were examined at Mt. Mikasa, Nara City, central Japan. Nagilactone content in mature leaves dropped sharply in May, when new leaves flushed. The nagilactone content of new leaves was far greater than that of mature leaves, implying a translocation of nagilactones from old leaves to new leaves. The total mass of nagilactones in the canopy was 3.9 kg/ha.     

建设同煤集团数字林业(绿化)的重要意义

阐述了数字林业(绿化)在林业(绿化)工作中的作用和意义。     

浅谈江西林产工业主要产品的现状与发展

对江西林产工业及其产品生产的现状进行分析,提出江西林产工业的发展对策:合理利用现有林业资源,调整产业结构,形成规模经济,推进林产工业发展。