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PubMed2003

[Advance in researches on the effect of forest on hydrological process].

According to the effects of forest on hydrological process, forest hydrology can be divided into three related aspects: experimental research on the effects of forest changing on hydrological process quantity and water quality; mechanism study on the effects of forest changing on hydrological cycle, and establishing and exploitating physical-based distributed forest hydrological model for resource management and engineering construction. Orientation experiment research can not only support the first-hand data for forest hydrological model, but also make clear the precipitation-runoff mechanisms. Research on runoff mechanisms can be valuable for the exploitation and improvement of physical based hydrological models. Moreover, the model can also improve the experimental and runoff mechanism researches. A review of above three aspects are summarized in this paper.

Conservation of Natural Resources↗
PubMed2003

[The temporal variations of soil respiration under different land use in Liupan Mountain forest zone].

The temporal variations of soil respiration under cropland, rangeland, natural secondary forest (brushwood, nature secondary forest dominated by Querces liaotungensis koiz or Populus davidiana dode) and the plantation of larch (13, 18 and 25-year-old Larix principis-rupprechtil mayr) in Liupan Mountain forest zone was studied. It was found that the rate of soil respiration increased with increasing soil temperature during diurnal variation and the highest temperature was from 13:00 o'clock to 15:00 o'clock, the lowest temperature was from 04:00 o'clock and 08:00 o'clock, the variation of soil respiration rate appeared same trend. The daily rate of soil respiration increased from May to October and which was the highest from August to September and declined on October. The diurnal or seasonal variation of soil respiration rate mainly consisted with the diurnal or seasonal variation of soil temperature and its range under cropland or rangeland was greater than which under forestland (natural secondary forest, plantation or brushwood). The highest rate of soil respiration for diurnal or seasonal variation of soil CO2 efflux under cropland or rangeland was higher than which under the forestland, while the lowest rate of soil respiration under cropland or rangeland was lowered than which under forestland. Annual rate of respiration for natural secondary forest, cropland, rangeland and plantation was 3.96-4.51 t/(hm2.a), 1.91 t/(hm2.a), 5.08 t/(hm2.a) and 4.11-5.55 t/(hm2.a) respectively. The results shows that the diurnal or seasonal variation range of soil respiration rate would increase with conversion from natural forests to cropland or rangeland, while which would decrease following afforestation under cropland or rangeland. In addition, the annual respiration rate would also change with change in land use.

Carbon Dioxide↗
PubMed2004

Forest malaria in Vietnam: a challenge for control.

Forest malaria is a complex but common phenomenon occurring in southeast Asia. We studied its epidemiology through a prospective community-based study in central Vietnam. A total of 585 individuals were followed for two years by active case detection and biannual cross-sectional surveys. The prevalence of antibodies to Plasmodium falciparum was constantly about 20% across surveys and the incidence rate of clinical episodes of P. falciparum malaria was 0.11/person-year. Multivariate analysis showed that regular forest activity was the main risk factor for clinical malaria and malaria infections. Untreated bed nets had a significant protective effect (60%), except for people regularly sleeping in the forest. The population-attributable fraction for regular forest activity was estimated to be 53%. Our results confirm the major role played by forest activity on the malaria burden in this area and provide the basis for targeting control activities to forest workers. New interventions based on insecticide-treated materials need to be urgently evaluated.

Adolescent↗
PubMed2004

[Dynamics of forest landscape boundary at Changbai Mountain].

By using Geographic Information System (GIS) and Remote Sensing (RS) technology combined with field investigation and correlation analysis, this study was aimed to explore the dynamics of forest landscape boundary at Changbai Mountain, and to reveal the relationships among landscape fragmentation and changes of landscape boundary indices. The results showed that in the last 20 years or so, tundra decreased by 3694.8 hm2, spruce and fir forest reduced by 130482.03 hm2, and Korean pine-hardwood and mountain birch forest increased by 41610.4 hm2 and 669.78 hm2, respectively. The forest landscapes at Changbai Mountain tended to be more fragmented, and the shape of the landscape boundary became more complicated due to timber harvesting, forest cutting for cropping, and other human activities such as tourism. The changes of landscape shape index (LSI), contrast weighted edge density (CWED), total weighted edge length (TE-WGT) and weighted landscape shape index (LSI-WGT) could be used as good indicators for the degrees of forest landscape fragmentations, which was approved by correlation analysis among landscape fragmentation and changes of landscape boundary indices. The degree of human activities on landscape could be reflected by landscape shape index.

China↗
PubMed2004

[The research on the law of greenhouse gases emission from warm temperate forest soils in Beijing region].

In situ measurements by closed chamber technique were done to investigate the law of greenhouse gases (Methane, carbon dioxide and Nitrous Oxide) fluxes emission from different warm temperate forest soils (Broad-leaved forest, Form. Quercus liaotungensis and Form. Pinus tabulae) of Dongling mountain in Beijing region. Results show that the all representative types forest soils were sink of CH4 and source of CO2 and N2O. Different type of vegetables and soils result of different fluxes range of the main greenhouse gases. The fluxes range of CH4, CO2 and N2O emission from the three types forest soils were: 42-103 micrograms/(m2.h), 15-344 mg/(m2.h) and -61-101 micrograms/(m2.h); 13-182 micrograms CH4/m2.h, 23-380 mg/(m2.h) and -15-183 micrograms/(m2.h); 12-128 ug CH4/m2.h, 15-292 mg/(m2.h) and -94-153 micrograms/(m2.h); respectively. The mean fluxes of CH4, CO2 and N2O emission from the three types forest soils during the observation period were: -66 micrograms/(m2.h), 145 mg/(m2.h) and 22 micrograms/(m2.h); -67 micrograms/(m2.h), 146 mg/(m2.h) and 45 micrograms/(m2.h); -79 micrograms/(m2.h), 150 mg/(m2.h) and 31 micrograms/(m2.h), respectively. The total amounts of CH4 CO2 and N2O emission from the three types forest soils were -5.34 kg/(hm2.a), 13.9 Mg/(hm2.a) and 2.58 kg/(hm2.a); -6.20 kg/(hm2.a), 14.07 Mg/(hm2.a) and 4.19 kg/(hm2.a); -6.85 kg/(hm2.a), 15.71 Mg/(hm2.a) and 4.30 kg/(hm2.a), respectively.

Carbon Dioxide↗
PubMed2004

[Ecological water requirement of forests in Loess Plateau].

Converting degraded farmlands to forest or grass lands is the best approach to reduce the soil erosion, the Loess Plateau is faced with most serious ecological disaster. Loess Plateau located in the arid and semi-arid regions is a fragile region with the characteristics of little precipitation and intensive evapotranspiration. Therefore, water is the most important factor limiting the eco-restoration and construction of the vegetation in the region. According to the latest digital land use map and with GIS, the ecological water requirement for forests in Loess Plateau was estimated, and by the water balance of the forest ecosystem in their growing season, the ecological water shortage was calculated. The results revealed that the minimum and suitable ecological water requirement of the forests in Loess Plateau were approximately 262.49 x 10(8) m3 and 421.34 x 10(8) m3 respectively. Accordingly, if it is taken the minimum ecological water requirement as the quota, the area of forests suffered water shortage was about 7,639.09 km2, 9.1% of all, and the ecological water shortage was amounted to 4.77 x 10(8) m3; if it is taken the suitable ecological water requirement as the quota, the forest land area suffered water shortage was about 57.7% of all, and the ecological water shortage was roughly 58.55 x 10(8) m3.

Altitude↗
PubMed2004

[Dynamics of soil fauna communities during succession process of secondary forests in Changbai Mountain].

The secondary succession of forest communities in Changbai Mountain might be divided into three stages, i.e., aggradation, transition, and steady states. The last stage will be arrived after about 100 years. At same time, the succession dynamics of various soil fauna groups were shown as: Saprophagous group was more abundant than other fauna groups, and its change trend was similar to the development of forest vegetation after disturbing; Phytophagous group had a higher amount during the prophase of forest succession, which was decreased with forest succession; the quantity of Carnivorous increased obviously after about 100-years-succession; and the composition of insect groups was that the unstable groups was more abundant when the forest was younger, but less abundant when the forest was older.

Animals↗
PubMed2004

[Research advances in dynamic mechanism and its simulation of eco-hydrological process in forest catchment].

Hydrological process is the key link between climatic fluctuations and ecologic dynamics of forests at spatial and temporal scales. To some extent, global climate change and large-scale human's activities will impact the spatial-temporal changes of eco-hydrological process in forest catchments in the future. Therefore, researches on the dynamic mechanism of eco-hydrological processes in forest catchments play a crucial role in understanding and controlling the rational use of ecological resources, resuming regional ecology, and sustainable development in economy. This paper described the interception, evapotranspiration and rainfall-runoff of forest ecological system and their effects on hydrological process. The spatial structure of soil moisture and its evolution with time were also the cause and consequence of forest. The spatial-temporal interaction between hydrologic and ecologic dynamics, the application of distributed hydrological model, and the eco-hydrological dynamics and cybernetics of forest would be the most exciting frontiers of the relative researches in the future.

Climate↗
PubMed2005

[CO2 concentration character in broad-leaved Korean pine forest of Changbai Mountains].

The CO2 concentration in broad-leaved Korean pine forest of Changbai Mountains was measured continuously with a CO2 infra-red analyzer in 2003. The results showed that the CO2 concentration in the forest had striking characteristics of temporal-spatial variations, which were mainly influenced by the physiological processes of plants, soil respiration, and intensity of turbulence exchange. In growing season, the daily maximum and minimum CO2 concentration appeared mostly on the surface floor at about 5:00 in the early morning and at canopy location at about 15:00 in the afternoon, respectively. There was an obviously process of forest CO2 emission when the inversion broke at dawn. The average CO2 concentration in forest was 377 micromol x mol(-1) in 2003, the maximum of monthly average appeared in January as 388 micromol x mol(-1), and the minimum of monthly average appeared in August as 352 micromol x mol(-1). The forest acted as CO2 source in night time and turned to sink in daytime, during growing season. In non-growing season, the forest acted as CO2 source in both daytime and night time, but still had a clear evidence of CO2 assimilation at noon, with canopy location during non-growing season.

Air↗
PubMed2005

[Research advances on BVOCs emission from forest].

BVOCs play an important role in atmospheric environmental quality, global tropospheric chemistry, and global carbon balance, while forest is the main sources of them. This paper summarized the seasonal and diurnal variations of BVOCs emission from forest and its affecting factors including habitat variation, environmental change, forest development phase and its physiological status, and exotic interference. The ecological significance of forest BVOCs emission was further discussed, and some suggestions were proposed on ecological healthcare forest resources exploitation and urban forest construction.

Air↗
PubMed2005

[Root biomass and underground C and N storage of primitive Korean pine and broad-leaved climax forest in Changbai Mountains at its different succession stages].

With more than 200 years old primitive Korean pine and broad-leaved climax forest and its two 20 and 80 years old secondary Populus davidiana and Betula platyphylla forests in Changbai Mountains as test objects, this paper studied their root biomass and underground C and N storage. The results showed that with forest succession, the root biomass of 20 years old, 80 years old, and climax forests was 2.437, 2.742 and 4.114 kg x m(-2), respectively. The root C storage was 1.113, 1.323 and 2.023 kg x m(-2), soil C storage was 11.911, 11.943 and 12.587 kg x m(-2), and underground C storage was 13.024, 13.266 and 14.610 kg x m(-2), respectively, while the root N storage was 0.035, 0.032 and 0.038 kg x m(-2), soil N storage was 1.207, 1.222 and 0.915 kg x m(-2), and underground N storage was 1.243, 1.254 and 0.955 kg x m(-2), respectively, which indicated that along with forest succession, forest underground became a potential "carbon sink", whereas underground N storage did not change obviously.

Betula↗
PubMed2005

[Forest ecosystem service and its evaluation in China].

Facing the relative lag of forest ecosystem service and estimation in China, this paper proposed to quickly carry out the research on the evaluation of forest ecosystem service. On the basis of the classification of forest ecosystem types in China, the service of artificial and semi-artificial forest ecosystems was investigated, which was divided into eight types, i.e., timber and other products, recreation and eco-tourism, water storage, C fixation and O2 release, nutrient cycling, air quality purifying, erosion control, and habitat provision. According to the assessment index system for global ecosystem service proposed by Costanza et al., a series of assessment index system suitable for Chinese forest ecosystem service was set up, by which, the total value of forest ecosystem service in China was estimated to be 30 601.20 x 10(8) yuan x yr(-1), including direct and indirect economic value about 1 920.23 x 10(8) and 28 680.97 x 10(8) yuan x yr(-1), respectively. The indirect value was as 14.94 times as the direct one. The research aimed to bring natural resources and environment factors into the account system of national economy quickly, and to realize the green GDP at last, which would be helpful to realize sustainable development and environment protection.

China↗
PubMed2005

[Biomass and carbon storage of ground bryophytes under six types of young coniferous forest plantations].

This paper studied the biomass and carbon storage of the ground bryophytes under young Picea balfouriana (P), Pinus tabulaeformis (Y), Pinus armandii (H), Larix kaempferi (L), Picea balfouriana-Pinus tabulaeformis (P-Y), and Pinus tabulaeformis-Pinus armandii (Y-H) forest plantations in the upper reach of Minjiang River, Sichuan Province. The results showed that total biomass and carbon storage of ground bryophytes were relatively low, being 3.11 - 460.36 kg x hm(-2) and 1.12 +/- 0.03 x 168.95 +/- 0.92 kg x hm(-2), respectively. On plot level, only the bryophyte biomass between forest P and others, and the carbon storage between forest L and others were significantly different. The ground bryophyte had the highest biomass and carbon storage under forest P, while the lowest ones under forest H. Comprehensive analysis suggested that forest type and its structural feature might be the important factors determining the biomass and carbon storage of ground bryophytes, and thinning was an important measure to improve ground bryophyte growth and biomass production.

Biomass↗
PubMed2005

[Construction of information management-based virtual forest landscape and its application].

Based on the analysis of the contents and technical characteristics of different scale forest visualization modeling, this paper brought forward the principles and technical systems of constructing an information management-based virtual forest landscape. With the combination of process modeling and tree geometric structure description, a software method of interactively and parameterized tree modeling was developed, and the corresponding renderings and geometrical elements simplification algorithms were delineated to speed up rendering run-timely. As a pilot study, the geometrical model bases associated with the typical tree categories in Zhangpu County of Fujian Province, southeast China were established as template files. A Virtual Forest Management System prototype was developed with GIS component (ArcObject), OpenGL graphics environment, and Visual C++ language, based on forest inventory and remote sensing data. The prototype could be used for roaming between 2D and 3D, information query and analysis, and virtual and interactive forest growth simulation, and its reality and accuracy could meet the needs of forest resource management. Some typical interfaces of the system and the illustrative scene cross-sections of simulated masson pine growth under conditions of competition and thinning were listed.

Computer Simulation↗
PubMed2006

[Microclimate edge effects of evergreen broad-leaved forest fragments in Jinyun Mountain: a preliminary study].

This paper studied the microclimate of continuous and fragmental evergreen broad-leaved forests in Jinyun Mountain by determining the horizontal gradient distribution of microclimate elements near forest edges. The results showed that there existed clear edge effects of microclimate in every edge of fragmental forests. The distinctions of maximum and minimum air temperature, photosynthetic active radiation, and minimum relative humidity between edge forest and interior forest were higher or greater, while that of maximum ground surface temperature was lower or smaller in dry season than in rain season. The edge effect was the smallest in the biggest fragmental patch, but the greatest in the smallest fragmental patch in interior forest.

China↗
PubMed2006

[Forest biomass carbon storage and its dynamics in Tanjiang River basin].

Based on an improved estimation method of forest carbon storage and the inventory of forest resources, this paper estimated the forest carbon storage and its dynamic changes in Tanjiang River basin, and analyzed the relationships of the carbon storage and its density with the increase of population density and GDP during the urbanization in 1990-2001. The results showed that the forest carbon storage in Tanjiang River basin increased from 5.906 x 10(6) t in 1990 to 7.852 x 10(6) t in 2001, with an annual average accumulation amount of 0.18 x 10(6) t or an annual average accumulation rate of 3.05%, and playing a role of carbon sink. The rapid increase of population density and GDP didn't influence the increase of forest carbon storage and density, but the development of forestry was far lower than that of economy. To have a better service function of forest ecosystem in the process of urbanization, and to promote the sustainable development of regional ecological environment, the key point is the reasonable coordination of forestry management with the development of economy.

Biomass↗
PubMed1991

A temporary focus of savanna species of the Simulium damnosum complex in the forest zone of Liberia.

Savanna species of the Simulium damnosum complex, the major vectors of the blinding savanna type of onchocerciasis, were considered to be rare in Liberia, until the dry season of 1988. In 1988 they became a serious nuisance, biting people at the Bong iron ore mine within the rain forest zone. S. damnosum s.str. and S. sirbanum were found breeding, in association with S. adersi a non man-biting savanna species, in a stream emerging from the mine's tailings pond. The local forest species were extremely rare in this stream. The water of the stream was characterized by an increased hardness and higher temperatures in comparison with those of natural watercourses in the area. The mass occurrence of flies was probably related to expansions of the tailings ponds, when rich nutrition was provided for the blackfly larvae by the decaying forests submerged by the rising water levels. The phenomenon did not recur in 1989 when only a few savanna flies were caught, and none were seen in the dry season of 1990. Although it is not known why the artificial environment of the tailings ponds was so attractive for the savanna species the events clearly demonstrated that savanna flies seasonally invading the area, possibly aided by the northeasterly harmattan winds, can become established in the rain forest zone if suitable conditions are met. No infections with Onchocerca volvulus were found in more than 1000 flies caught by vector collectors but, after experimental infection with the local forest strain, a few parasites developed to the infective stage. As yet there is no evidence that the occurrence of savanna flies in the rain forest zone of Liberia was of epidemiological significance.

Animals↗
PubMed1991

[Relationships between the pollen productions in sugi (Cryptomeria japonica D. Don) forests and the patterns of atmospheric scattering pollens in Toyama Prefecture--the example of Toyama Prefecture in 1990].

We investigated the geographical distribution of sugi (Cryptomeria Japonica D. Don) forests and the male flower-setting conditions of them in Toyama prefecture. The relationships between our findings and the atmospheric pollen scattering patterns were also studied. The results were as follows. 1. Atmospheric pollen counts and their scattering patterns were fairly easily explained by the geographical distribution of 30-year old sugi forests, the male flower-setting conditions and the first day pollen was scattered in those forests. 2. Total atmospheric counts and maximum sugi pollen peaks were significantly affected by the proximity of sugi forests at altitudes of less than 200 meter. 3. In the atmospheric pollen survey, the detected pollen counts decreased according to the distance between the observation sites and the sugi forests. And few pollen grains were observed from natural sugi forests growing at distances of 20 km to 30 km from the observation sites.

Air↗