森林采运作业个体伤害的工效学分析

森林采运作业是一种高危险作业,有效减少作业过程中的生产事故和作业人员个体伤害是企业安全管理工作的核心,本文运用系统工程学原理和人类工效学方法全面系统的分析了森林采运作业生产事故和作业人员个体伤害的致因,提出了减少采运作业生产事故和作业者个体伤害的对策。为采运企业安全生产管理提供了科学的决策依据。     

Streamwater chemistry and flow dynamics along vegetation-soil gradient in a subalpine Abies fabri forest watershed, China

Streamwater chemistry and spatial flow dynamics from a subalpine Abies fabri forest in an experimental watershed located in the east slope of Gongga Mountain were analyzed to gain insights into the gradient effect of primary community succession on the stream biogeochemical process. Results showed that high sand content (exceeding 80%) and porosity in the soil(exceeding 20% in A horizon and 35% in B horizon), as well as a thick humus layer on the soil surface, made the water exchange quickly in the Huangbengliu (HBL) watershed. Consequently, no surface runoff was observed, and the stream discharge changed rapidly with the daily precipitation. The flow trends of base ions in the stream water were influenced by the Abies fabri succession gradient. Ca^2 , HCO3^- and SO4^2,- were the dominant anions in the streamwater in this region. A significant difference of Ca^2 , HCO3^- and SO4^2- concentration exported between the succession stages in the watershed can be found. But they had the similar temporal change in the stream flow. Ca^2 , HCO3^- and SO4^2- showed significantly negative correlations with the daily precipitation and the stream discharge. Concentrations of Cl^- , Na^ , K^ , and Mg^2 were low in all streamwaters monitored and we observed no differences along the Abies fabri succession gradient. Low ratios of Na. (Na Ca) (range from 0.1 to 0.2) implied cations were from bedrock weathering (internal source process in the soil system) in this region. But, a variance analysis showed there were almost no differences between rainwater and streamwaters for Mg^2 , Na^ , K^ , and Cl^- concentrations. This indicated that they might be come from rainfall inputs(external source). The highly mobile capacity, rapid water exchange between precipitation and discharge, and long-term export lead to this observed pattern were suggested.     

1990~2020年阿克苏河流域土地利用碳排放时空轨迹与影响因素

土地利用变化会导致不同类型碳源和碳汇功能变化,是碳排放的关键来源.从土地利用变化的角度开展阿克苏河流域碳排放及其影响因素研究,对于促进流域山水林田湖草沙冰一体化保护修复、助力碳达峰与碳中和目标实现具有重要意义.基于1990~2020年的4期土地利用数据与同期社会经济数据,测算土地利用碳排放总量,探究土地利用碳排放时空轨迹及其影响因素.结果表明:①1990~2020年,耕地、林地、建设用地和未利用地整体呈增加趋势,草地和水域呈减少态势.土地利用类型空间变化特征主要表现为草地、未利用地转换为耕地;②1990~2020年流域净碳总排放量呈现持续上升趋势,累计增加了14.78×10⁴ t,耕地面积增加是引起流域净碳排放量增长的关键因素;③流域土地利用碳排放量空间上呈中间高四周低的分布格局,净碳排放量显著变化区域主要分布在温宿县南部、阿克苏市、阿瓦提县及阿拉尔市;④人类活动对土地利用碳排放驱动作用最强且其影响由东部向西部逐渐增大,年均气温对土地利用碳排放影响贡献主要集中在阿克苏市东部和阿瓦提县北部,年均降雨量对温宿县北部和阿合奇县西部的抑制作用较强.     

我国北方沙尘暴与植被覆盖度关系研究

利用NOAA/AVHRR和旬归一化植被指数NDVI数据,计算了1983-2000年中国北方13省市区的植被覆盖度,分析了这些地区植被覆盖度的时间变化趋势和空间分布规律,研究了中国北方沙尘暴与植被覆盖度之间的关系。结果表明:我国北方沙尘灾害频次与植被覆盖度有很好的对应关系,1983-2000年的18年间,我国北方大部分地区植被覆盖度增加,这段时期沙尘灾害频次总体呈降低趋势,其中20世纪80年代我国北方大部分地区植被覆盖度增加,这一时期我国北方沙尘暴发生频数下降;20世纪90年代,我国北方大部分区域植被覆盖度呈下降趋势,特别是华北和西北干旱与半干旱地区,下降趋势显著,这一时期我国北方沙尘暴发生频数在减少中有回升趋势。研究结果表明,植被覆盖度是影响中国北方沙尘暴频次变化的重要因素。     

Mineral constituents in Leccinum scabrum from lowland locations in the central Europe and their relation to concentration in forest topsoil

Leccinum scabrum is an edible mushroom common in European regions in the northern hemisphere. Macro and trace mineral constituents such as Ag, Al, Ba, Ca, Cd, Co, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, P, Rb, Sr and Zn were studied in L. scabrum and in the top soil collected from the same location underneath soil substratum. The “pseudo-total” and labile (extractable fraction of minerals) were measured to get insight into the levels, distribution between the morphological parts of fruiting bodies, potential for their bioconcentration by mushroom and evaluated for human exposure via consumption of the mushroom. The sampling sites include the Dar?lubska Wilderness, Trójmiejski Landscape Park, Sobieszewo Island, Wdzydze Landscape Park and outskirts of the K?trzyn town in Mazury from the norther part of Poland. Median values of K, Rb and P concentrations in dehydrated L. scabrum were for caps in range 27,000–44,000 mg kg^?1, 90–320 mg kg^?1 and 6,200–9,100 mg kg^?1, and followed by Mg at 880–1,000 mg kg^?1, Ca at 48–210 mg kg^?1 and Al at 15–120 mg kg^?1. The median concentrations of Cu, Fe, Mn and Zn in caps were in range 15–27 mg kg^?1 db 38–140 mg kg^?1, 5.3–27 mg kg^?1 and 130–270 mg kg^?1. For Ba and Sr, concentrations on the average were at ～1 mg kg^?1, and almost equally distributed between the caps and stipes of the fruiting bodies. L. scabrum mushrooms were low in toxic Ag, Cd, Hg and Pb, for which the median values in dried caps from five locations were, respectively, in range 0.48–0.98 mg kg^?1 (cap to stipe index, Q_C/S, was 2.5–4.1), 1.0–5.8 mg kg^?1 (Q_C/S 2.9–3.8), 0.36–0.59 mg kg^?1 (Q_C/S 1.6–2.7) and 0.20–0.91 mg kg^?1 (Q_C/S 1.2–1.9). Substantial variations in the concentrations of the “pseudo-total” fraction (extracted by aqua regia) or labile fraction (extracted by 20% solution of nitric acid) of the elements determined in forest topsoils were noted between some of the locations examined. The elements K, P, Cd, Cu, Hg, Mn, Na, Rb and Zn can be considered as those which were bioconcentrated by L. scabrum in fruiting bodies, while the rates of accumulation varied with the sampling location.     

Patterns and drivers of forest land cover changes in tropical semi-deciduous forests in Ghana

This study was conducted to determine the patterns and drivers of forest land cover changes in Bobiri and Oboyow Forest Reserves (BFR and OFR, respectively), Ghana. Landsat images were employed to determine forest land cover types and changes in 1990, 2000 and 2010 using supervised classification method. Factors that drive forest land cover changes in the forest reserves were determined using a semi-structured questionnaire and field observations. Generally, closed-canopy forest decreased by 49% in both forests over 20-year period resulting in a tremendous increase in open-canopy forest (BFR: 85%; OFR: 46%) and non-forest land cover types (BFR: 48–80% OFR: 127–350%). Factors such as logging manual illiteracy among timber operators, offences of authorised timber operators, ineffective community participation, harvesting schedule revision, chainsaw logging, illegal logging, bushfires, fuel gathering and weak penalty for offences were identified as contributing to rapid depletion of closed canopy forest cover in the forest reserves.     

落叶阔叶林释放异戊二烯的研究

生物释放的烯烃是全球气候变化和温室效应研究的重要内容之一。本研究在国内首次测定了华北落叶阔叶林内１０种乔、灌木的异戊二烯释放率,分别在０－１．２８μｇ．ｇ＾－１．Ｈ＾－１之间。探讨了林内异戊二烯的时空分布规律。发现高释放树种辽东栋的异戊二烯释放率呈昼夜周期性变化,在１４：００达到１．９２μｇ．ｇ＾－１．Ｈ＾－１,夜晚几乎降为０。对各环境因子进行排序：光照与异戊烯率的关系最为密切（ｒ＝０．８６５０）     

Influences of Climatic Change on Some Ecological Processes of an Insect Outbreak System in Canada's Boreal Forests and the Implications for Biodiversity

Insect outbreaks are a major disturbance factor in Canadian forests. If global warming occurs, the disturbance patterns caused by insects may change substantially, especially for those insects whose distributions depend largely on climate. In addition, the likelihood of wildfire often increases after insect attack, so the unpredictability of future insect disturbance patterns adds to the general uncertainty of fire regimes. The rates of processes fundamental to energy, nutrient, and biogeochemical cycling are also affected by insect disturbance, and through these effects, potential changes in disturbance patterns indirectly influence biodiversity. A process-level perspective is advanced to describe how the major insect outbreak system in Canadian forests, that of the spruce budworm (Choristoneura fumiferana Clem. [Lepidoptera: Tortricidae]), might react to global warming. The resulting scenarios highlight the possible importance of natural selection, extreme weather, phenological relationships, complex feedbacks, historical conditions, and threshold behavior. That global warming already seems to be affecting the lifecycles of some insects points to the timeliness of this discussion. Some implications of this process-level perspective for managing the effects of global warming on biodiversity are discussed. The value of process-level understanding and high-resolution, long-term monitoring in attacking such problems is emphasized. It is argued that a species-level, preservationist approach may have unwanted side-effects, be cost-ineffective, and ecologically unsustainable.     

Macrobenthic Monitoring in the Lower St. Johns River, Florida

The macrobenthos in the oligohaline 132 km reach of the Lower St. Johns River, Florida, is an unusual blend of freshwater and marine organisms within the annelid, mollusk, aquatic insect, and crustacean groups. During 1993–1994, the community composition was freshwater-oriented in the 47 km (seg I) and estuarine-dominated in the lower 85 km (seg II). Of the total 146 taxa collected, 89% were euryecious 'eutrophic' and 'pollution-tolerant' organisms. Densities ranged between 5000 and 20 000 individuals/m² ann av and maximum densities (85 000 individuals/m²) occurred in the muck substrate at the confluence of major tributaries and embayments. Throughout the lake-like seg II, benthic hypoxia existed during much of summer through fall. Biotic index values for grab, artificial substrate, and sled trawl samples reflected greatest stresses to the macrobenthos then. Both low taxonomic diversity and densities of organisms at the most downriver stations nearest the port of Jacksonville indicated that toxic substances also adversely affected the macrobenthos. Maintenance of the narrow band of littoral submerged aquatic vegetation (SAV) and adjacent shoreline riparian vegetation is important to sustain macrobenthic communities and other kinds of aquatic life in the river.     

Drivers of future streamflow changes in watersheds across the Northeastern United States

Accurate projections of streamflow, which have implications for flooding, water resources, hydropower, and ecosystems, are critical to climate change adaptation and require an understanding of streamflow sensitivity to climate drivers. The northeastern United States has experienced a dramatic increase in extreme precipitation over the past 25 years; however, the effects of these changes, as well as changes in other drivers of streamflow, remain unclear. Here, we use a random forest model forced with a regional climate model to examine historical and future streamflow dynamics of four watersheds across the Northeast. We find that streamflow in the cold season (November–May) is primarily driven by 3-day rainfall and antecedent wetness (Antecedent Precipitation Index) in three rainfall-dominant watersheds, and 30-day rainfall, antecedent wetness, and 30-day snowmelt in the fourth, more snowmelt-dominated watershed. In the warm season (June–October), streamflow is driven by antecedent wetness and rainfall in all watersheds. By the end of the century (2070–2099), cold season streamflow depends on the importance placed on snow in the machine learning model, with changes ranging from −7% (with snow) to +40% (without snow) in a single watershed. Simulated future warm season streamflow increases in two watersheds (56% and 193%) due to increased precipitation and antecedent soil wetness, but decreases in the other two watersheds (−6% and −27%) due to reduced precipitation.