Deciduous Broad-leaved Forest Research Articles

Distribution status, driving force, and protection suggestions of vegetation in Jiangsu Province, China

To provide support for the drawing of 1:500000 vegetation maps and vegetation protection in Jiangsu, the researchers performed a review on the history of research, distribution pattern, change and driving force of vegetation in Jiangsu Province, according to the research results and field investigation of Jiangsu vegetation in recent years. The series research work of the Jiangsu vegetation map began in 1964, and the final map was published in 2001. Vegetation in Jiangsu includes cultivited vegetation, planted and natural forests, herbaceous swamps, meadows, and sparse shrub grass. Cultivited vegetation is distributed in most flat areas, which mainly includes Zea mays , Triticum aestivum , and Oryza sativa . Natural forests are primarily distributed in Xuzhou, Lianyungang, Yili, and Ningzhen mountains. The natural forests include the coniferous forests such as Pinus massoniana , Pinus densiflora forests; the deciduous broad-leaved forests such as Quercus variabilis , Quercus acutissima , and Liquidambar formosana forests; the evergreen broad-leaved forests such as Quercus glauca and Schima superba forests; the bamboo forests such as Phyllostachys heterocycle forest; the coniferous and broad-leaved mixed forests such as Pinus massoniana and Quercus variabilis mixed forests; the evergreen and deciduous broad-leaved mixed forests such as Castanopsis sclerophylla and Quercus glauca mixed forests. Planted forests are mainly distributed in the northern Jiangsu, Lixiahe and coastal plains, including Populus spp, Platycladus orientalis , Cunninghamia lanceolate , and Pinus massoniana forests. The natural wetland vegetation is mainly distributed in the Yancheng coastal wetlands, with Phragmites communis , Spartina anglica , and Spartina alterniflora marshes. Compared with the vegetation in 1983, the area of forests represented by Pinus massoniana , Platycladus orientalis , and Robinia pseudoacacia forests decreased, and herbaceous grasslands and meadows were also drastically reduced. The salt meadows of the coastal wetlands were succeeded by Spartina anglica and Spartina alterniflora swamps, and large areas of agricultural vegetation and a part of the natural forest vegetation were transformed into towns. Human activities led by urbanization affected the distribution pattern of the vegetation in Jiangsu as the major driving force for vegetation change. According to the current situation of natural vegetation in Jiangsu, three suggestions were proposed to protect natural vegetation communities. First, ecological red line protection zones should be established in Nanjing Mufu Mountain, Zhenjiang Baohua Mountain, Lianyungang Shazhou Bay, etc., where the vegetation suffered grave human interference. Second, the development and utilization of herbs and coastal cofferdam, such as Mentha canadensis and Pseudostellaria heterophylla , should be more meticulous. Third, it is necessary to enhance the control of invasive plants, such as Spartina anglica , Solidago canadensis , and Alternanthera philoxeroides .

Forest characteristics, population structure and growth trends of Pinus yunnanensis in Tianchi National Nature Reserve of Yunnan, southwestern China

Aims: Pinus yunnanesis is commercially, culturally and economically important, but there is a lack of ecological data on its role in stand dynamics. Our aims are to clarify the structure, composition, regeneration and growth trends of primary mature P. yunnanensis forests. Study area: The Tianchi National Nature Reserve in the Xuepan Mountains, Yunlong County, northwestern Yunnan, China. Methods: We investigated forests containing P. yunnanensis, measured tree ages and analyzed the data. Results: Six forest types were identified: (1) coniferous forest: Pinus yunnanensis (Type 1); (2) mixed coniferous and evergreen broad-leaved forest: P. yunnanensis-Lithocarpus variolosus (Type 2); (3) mixed coniferous and deciduous broad-leaved forest: P. yunnanensis-Quercus griffithii (Type 3); (4) mixed evergreen broad-leaved and coniferous forest: Castanopsis orthacantha-P. yunnanensis-Schima argentea (Type 4); (5) mixed coniferous, evergreen and deciduous broad-leaved forest: Pinus yunnanensis-Schima argentea-Quercus griffithii (Type 5); (6) mixed coniferous and evergreen broad-leaved forest: Pinus armandii-Quercus rehderiana-Pinus yunnanensis (Type 6). The size- and age-structure and regeneration patterns of P. yunnanensis were highly variable within these six forest types. P. yunnanensis regeneration was well balanced in forest Type 1 as compared to the other five types. All six forest types were identified as rare and old-growth with P. yunnaensis trees reaching ages of more than 105 years (a maximum age of 165 years with a diameter 116 cm at breast height) except for the Type 4 forest (a 90-year-old stand). Growth rates of P. yunnanensis, based upon ring width measurements, were high for the first 10 years, then declined after the 10th year. In contrast, basal area increment (BAI) increased for the first 25 years, plateaued, and only declined as trees became older. Trees in the older age classes grew more quickly than younger trees at the same age, a consequence of either site quality or competitive differences. The BAI of P. yunnanensis in all age classes in the Tianchi National Nature Reserve was much higher than those of the secondary and degraded natural P. yunnanensis forests of other areas. Conclusions: The P. yunnanensis forests of the Tianchi area appear to be some of the last remnants of primeval and old-growth forests of this species. These forests are structurally diverse and contain a rich diversity of overstory, mid-story, and understory species. Taxonomic reference: Editorial Committee of Flora Republicae Popularis Sinicae (1959–2004) for vascular plants. Abbreviations: BA = basal area; BAI = basal area increment; DBH = diameter at breast height; H = height; RBA = relative basal area.

Impacts of ENSO events on forest fire weather of China

The ENSO events affect climate and fire danger of China. It would be helpful for improving fire danger forecast to understand the impacts of ENSO events on fire weather for various ecological zones in the country. We calculated the fire weather index (FWI) using the daily climatic dataset (V3.0) of international exchange weather stations in China during 1951-2016. The burned areas in forests for each ecological zone in 2001-2016 were derived from MODIS fire products. Temperature, precipitation, FWI and burned areas in fire season were estimated for each ecological zone by ENSO events (weak, medium, strong, and super strong El Niño events and weak, medium, and strong La Niña events). The results showed that there were 19 El Niño events and 14 La Niña events during 1950-2016. The average daily maximum temperature of the spring fire season increased significantly in the northwestern region with the influence of strong or super strong El Niño event, while the temperature reduced significantly in the medium El Niño event for mid-temperate semi-arid grassland. Precipitation in fire season generally increased in El Niño events in southern and southwestern forest regions. It would be reduced in most areas affected by the low and medium intensity La Niña event, but be increased during the strong La Nina event. The fire weather indices of southern forest regions decreased due to the weak El Niño event. The FWI of the northern forest regions increased with the strong or super strong El Niño event, and reduced in the southern and southwestern forest areas. There was a significant spatial difference on the FWI for some ecological zones with the impacts of the El Niño/La Niña events. The burned areas showed a consistent change trend with seasonal severity rating (SSR) during 2001-2016 when the SSR changed significantly for the regions of deciduous broad-leaved forest in humid/semihumid areas of warm temperate zone, broad-leaved forest in the middle north subtropical humid areas, and broad-leaved forest in tropical and subtropical humid areas. The burned areas in the rest regions were not affected by the ENSO events.

Influences of forest gaps on soil physico-chemical and biological properties in an oriental beech (Fagus orientalis L.) stand of Hyrcanian forest, north of Iran

Abstract: Understanding the effects of silvicultural practices including single-tree selection on soil properties is essential for forest management in temperate broadleaved beech forests. Changes in physico-chemical and biological soil properties in 15 harvest-created gaps under single-tree selection and the adjacent closed canopies, with five replications for each, were studied 6 years after gap creation in an oriental beech (Fagus orientalis L.) stand of the Hyrcanian forest. Gaps were classified into three size classes: small (85-130 m2), medium (131-175 m2) and large (176-300 m2). Soil cores were collected at the center and at the edge of gaps, and under the adjacent closed canopy. Results indicated that gap size significantly affected soil texture and bulk density, whereas soil organic carbon (SOC), total nitrogen and pH showed a significant gradient from the center to the edge of gap independently form their size. SOC and total nitrogen at the center of gaps were also significantly lower than closed-canopy, in particular for the medium-gap; contrastingly, the bulk density with the highest mean value was found at the center of the large-gap. Gap size had no significant influence on soil microbial biomass. These results highlighted that similar conditions in terms of many soil properties were still present among gaps and adjacent closed-canopy stands six years after logging, though canopy openness triggered a reduction in carbon and nitrogen availability along with the related microbial activity at the center of gaps, independently from their size. Therefore, if aimed at preserving an uneven aged structure along with soil quality in temperate broadleaved deciduous forest as the oriental beech stands in the Hyrcanian region, single-tree selection practice for harvesting trees can be recommended as sustainable forest management type.

Soil quality assessment under different forest types in the Mount Tai, central Eastern China

Forest soils, are important components of forest ecosystems and can be influenced by forest vegetation. Evaluating soil quality of forests is essential for sustainable forest management and forest ecosystem functions. We evaluated soil quality of seven forest stands (I: Pinus tabulaeformis × Alnus sibirica, II: Pinus tabulaeformis, III: Robinia pseudoacacia, IV: Pinus tabulaeformis × Platycladus orientalis,V: Pinus densiflora × Platycladus orientalis, VI: Platycladus orientalis × Sophora japonica,VII: Platycladus orientalis) in Mount Tai, Central Eastern China. Seventeen soil physical, chemical and biological properties were analyzed at 0–20 and 20–40 cm, respectively. Soil quality index (SQI) was determined using the established minimum data set (MDS) based on the selection results of principal component analysis (PCA). Non-capillary porosity, water holding capacity (WHC), total nitrogen (TN), total phosphorus (TP), available potassium (AK), and catalase were finally selected into the MDS. The mean SQI values of seven forest stands were calculated ranging from 0.253 (V) to 0.630 (I). Forest types of deciduous broad-leaved forest and needle-broadleaf mixed forest had higher soil quality in the study area. WHC, soil organic matter, TN and AK, altitude appeared to be the main limiting factors of soil quality. Our results demonstrate that the SQI based on the MDS method could be a useful tool to indicate the soil quality of forest systems, SQI can be viewed as a primary indicator of sustainable forestry management.

A major environmental shift by the middle Eocene in southern China: Evidence from palynological records

The modern environment of southern China is dominated by a humid monsoon climate, and presents a striking contrast to the widespread deserts found at similar latitudes elsewhere. The formation of a monsoon climate marks a major environmental shift in southern China during the Cenozoic; however, the origin and possible driving mechanism of the climate transition remain unclear. Paleogene palynological records from seven basins across southern China offer an exceptional opportunity to address this knowledge gap. The Paleogene palynoflora reveals two completely different vegetation and climate patterns: the Paleocene to early Eocene was characterized by a relatively high abundance of xerophilous taxa, suggesting an arid/semi-arid climate; while the middle Eocene to Oligocene supported subtropical wet evergreen and deciduous broad-leaved mixed forest, characterized by a significant increase in broad-leaved, coniferous taxa and the almost complete disappearance of xerophilous taxa, together indicating the emergence of a warm–humid climate at this time. Combined palynological, sedimentological, paleozoological, and paleobotanical proxy evidence reveal that the major environmental transition occurred roughly around the middle Eocene; this transition may mark the establishment of the monsoon climate. Furthermore, middle Eocene climatic parameters obtained through the Coexistence Approach (CA) were compared with those of modern sites with known climate regimes. The middle Eocene parameters were most similar to those exposed to the modern East Asian Monsoon (EAM), further indicating that the middle Eocene climate of southern China was predominantly influenced by the EAM. The evolution of the Paleogene palynoflora in southern China is largely consistent with global climate change. We infer that the enhancement of the East Asian winter monsoon (EAWM) during the middle Eocene was closely related to long-term global cooling, while the intensified East Asian summer monsoon (EASM) was primarily caused by the northward drift of the Indian Subcontinent and the uplift of the Tibetan Plateau.

A species composition dataset of a typical subtropical mixed evergreen and deciduous broad-leaved forest in karst ecosystem (2014)

A species composition dataset of a typical subtropical mixed evergreen and deciduous broad-leaved forest in karst ecosystem (2014)

China's national nature reserve network shows great imbalances in conserving the country's mega-diverse vegetation

The National Nature Reserve (NNR) network forms a central element in China's governmental strategy to conserve the country's vast biodiversity and its varied ecosystems. Nonetheless, the effectiveness of the existing NNR network in protecting China's highly diverse habitats and the fauna and flora they contain has remained unclear. Here, we analyze how comprehensively the existing NNR network protects China's vegetation diversity, identifying potential gaps to inform future NNR designations. Covering ~15.7% of China's land area, the existing nature reserve network contains 18 main vegetation types and 26 sub-types. All main vegetation types are also contained in the National-level Nature Reserves (NNRs), but to highly differing degrees. NNRs cover ~24.0% of China's grasslands, but only ~3.3% of the country's monsoon forests. With regards to main vegetation regions, about 41.4% of the Qinghai-Xizang Plateau is covered by NNRs, in contrast to only ~4.6% of the region representing warm-temperate deciduous broad-leaved forests. In five main vegetation regions, NNRs cover <10% of the area and are scattered across a highly fragmented network, leading for example to China's highly biodiverse subtropical evergreen broad-leaved forests being conserved only in small, isolated NNRs. NNRs also greatly vary in the number of vegetation types they individually comprise, with only 64 NNRs (18.9%) individually containing >50% of the vegetation types in their respective region. Overall, NNR size increases and fragmentation decreases from China's south-east to its western provinces. The resulting, extremely uneven distribution of NNRs across China limits their effectiveness in protection the country's plant diversity treasure trove. The country's NNR network therefore needs significant adjustments to effectively conserve China's valuable natural resources for future generations.

Consequences of Spatial Heterogeneity of Forest Landscape on Ecosystem Water Conservation Service in the Yi River Watershed in Central China

Forest landscapes, especially their spatial heterogeneity, play a key role in sustaining the ecosystem water conservation service in a watershed. However, this domain has not been fully investigated. This study uses the Yi River watershed in central China as the study site. We calculated the water conservation amounts of different forests through the water balance method and quantified the landscape spatial heterogeneity of forests using landscape metrics. Then we ran correlation analysis to find the correlating relationship between the landscape spatial heterogeneity of forests and the ecosystem water conservation service. We finally applied a redundancy analysis to explore the respective influencing strength of the landscape compositional heterogeneity and configurational heterogeneity of forests on the water conservation service. Results indicate that: (1) The area proportion of different forests has a significant impact on the spatial distribution of the water conservation service. When mixed forest is dominant and its area proportion is much greater than that of other forests, the generation of the water conservation service can be best enhanced; (2) Changes of the landscape compositional heterogeneity and configurational heterogeneity of forests can affect the water conservation service to different degrees. In particular, the landscape spatial heterogeneity of mixed forest has the greatest impact on this ecosystem service; (3) The landscape configurational heterogeneity of deciduous broad-leaved forest and mixed forest has a greater impact on the water conservation service than the landscape compositional heterogeneity, whereas that of evergreen needle-leaved forest has the opposite effect. In general, appropriately adjusting the combination and configuration of different forests in a watershed can effectively promote the generation of the ecosystem water conservation service. This study provides a scientific basis for future forest management with a view to improving the landscape sustainability of forests.

Hydrological fluxes of dissolved organic carbon and total dissolved nitrogen in subtropical forests at three restoration stages in southern China

In the restoration of subtropical forests, the hydrological fluxes of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) have not been fully investigated in different stages dominated by different tree species. The concentrations of DOC and TDN in rainfall, throughfall, stemflow, and surface runoff were measured for two years in each of the three forests at different restoration stages: early coniferous forest (Pinus massoniana - Lithocarpus glaber), intermediate deciduous broadleaved forest (Choerospondias axillaris), and late evergreen broadleaved forest (L. glaber - Cyclobalanopsis glauca). Input and output fluxes as well as leaching and migration coefficients of DOC and TDN were calculated to examine the nutrient cycling status in the processes of forest restoration. In stemflow, DOC concentrations in the evergreen broadleaved forest differed significantly from those in the coniferous and deciduous broadleaved forests, whereas TDN concentrations differed significantly between the coniferous forest and other two forests. In throughfall, DOC and TDN concentrations were not significantly different among the three forests. The amount of DOC leached was primarily influenced by rainfall and was significantly related to fluxes in throughfall, with the highest value in the deciduous broadleaved forest (57.78 kg C ha−1). However, the amount of TDN leached was affected by rainfall and the absorption of vegetation and was not significantly related to fluxes in throughfall, except for the deciduous broadleaved forest. The highest value of TDN leached was in the coniferous forest (11.90 kg N ha−1). Mean TDN concentration in surface runoff tended to increase but annual TDN output fluxes decreased with forest restoration. However, both mean concentration and annual output fluxes of DOC in surface runoff were the highest in the deciduous broadleaved forest at the intermediate restoration stage. The concentrations were closely related to surface runoff, decomposition rate of litterfall, and soil organic matter content. The annual output fluxes of DOC and TDN in surface runoff were less than 30% of the input in throughfall, indicating nutrient accumulation in subtropical secondary forests.

Carbon and Nutrient Inputs by Litterfall in Evergreen and Deciduous Forests in Korea

Knowledge about carbon and nutrient fluxes by litterfall is important for understanding nutrient cycling in geologically unique ecosystems. However, the determination of forest litterfall production patterns is difficult due to many biophysical factors influencing the process. In this study, we (1) quantified the litterfall production and carbon and nutrient fluxes in warm-temperate evergreen forest stands in Jeju Gotjawal and (2) compared these values to those of a typical cool-temperate deciduous forest stand by forest types and climate differences. Litterfall from evergreen broadleaved forests at Cheongsu (CS) and Seonheul (SHb), a mixed forest at Seonheul (SHm) in Jeju Gotjawal, and a deciduous broadleaved forest at Chungnam National University Forest (CNU) was collected for a full two years using litter traps. Samples were sorted into leaves, twigs, barks, seeds, and unidentified materials, and then weighed and measured for C, N, P, K, Ca, and Mg fluxes by litterfall. Results showed that the mean annual litterfall (846.3 g m−2, average of CS, SHb, and SHm) at Jeju Gotjawal was similar to that of CNU (885.5 g m−2), but varied by site in Jeju Gotjawal: CS (933.1 g m−2) was significantly higher than the average of SHb and SHm (802.9 g m−2). Seasonal patterns of litterfall production differed by forest types; evergreen broadleaved forests showed a bimodal peak in fall and spring while deciduous broadleaved forests showed a unimodal peak in fall. Jeju Gotjawal had significantly higher total macronutrient concentrations and contents (except for K) than CNU and they also varied by site in Jeju Gotjawal: CS had higher N, P, Ca, and Mg contents than SHb and SHm. We conclude that litterfall production and nutrient fluxes differed by forest stand as influenced by forest types and climate. Further, our findings are important for understanding carbon and nutrient dynamics in the geologically unique ecosystem of Jeju Gotjawal and other areas with similar characteristics.

Pleistocene vegetation in Guangxi, south China, based on palynological data from seven karst caves

Pleistocene cave deposits usually provide ideal materials for the study of mammals. Karst caves in Chongzuo, Guangxi Zhuang Autonomous Region of south China are famous for numerous studies on their abundant mammalian fossils and most importantly, Homo sapiens. Unfortunately, the environmental backgrounds, e.g. vegetation and climate, that governed these faunas, are usually lacking because there is no appropriate proxy. In this work, we analysed the palynological assemblages from seven well-dated karst caves in Chongzuo. The ages of these seven caves (2.0–0.11 Ma) cover almost the entire Pleistocene. Though the number of pollen and spores is comparatively low, as expected, we managed to reconstruct the principle vegetation types. The results show that the individual vegetations were mainly warm temperate to subtropical evergreen and deciduous broad-leaved mixed forests. The present study provides important background environmental information on the Pleistocene faunas and Homo sapiens in Guangxi, south China.

Life form dynamics of the tree layer in evergreen and deciduous broad-leaved mixed forest during 1996–2017 in Tianmu Mountains, eastern China

In the forest areas of eastern China, there is a change from forest dominated by deciduous broad-leaved trees to forest dominated by evergreen broad-leaved trees as the latitude or altitude decreases. Different life forms have different survival strategies to deal with climate change, and studying the life form dynamics of the tree layers in the mixed forest in eastern China, with increasing temperature, can help us understand how the forest responds. This study was performed in a 1 ha plot in evergreen and deciduous broad-leaved mixed forest in Tianmu Mountain National Nature Reserve. Based on the data from two surveys (1996 and 2017), the changes in life form composition and biodiversity over the past 21 years were analyzed. We obtained the following results: (1) The proportion of evergreen trees increased from 55.0% in 1996 to 67.5% in 2017, and the dominance of evergreen species was enhanced. (2) The diversity of both life forms increased, and the tree species were more abundant. (3) The average annual recruitment rate of the evergreen species was 2.1% greater than their mortality rate, and the average annual recruitment rate of the deciduous species was 0.5% less than their mortality rate. (4) The competition among the trees in the small-diameter class (10 cm ≤ DBH &lt; 20 cm) was fierce for many tree species. The proportion of the evergreen species in the small-diameter class was high. The life forms making up the mixed climax forest community has changed over the past 21 years, with the proportion and dominance of evergreen trees increasing significantly.

Spatial distribution pattern and interspecific correlation analysis of main species of Rosaceae in a deciduous broad-leaved forest in Yaoluoping

Spatial distribution pattern and interspecific correlation analysis of main species of Rosaceae in a deciduous broad-leaved forest in Yaoluoping

中国森林面积变化及其温室气体储量模拟研究

PDF HTML阅读 XML下载 导出引用 引用提醒 中国森林面积变化及其温室气体储量模拟研究 DOI: 10.5846/stxb201812312853 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41671425，41401504） Modeling greenhouse gas sequestration potential of forest change in China Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:陆地生态系统承载的温室气体对全球碳循环及气候调节服务意义重大，森林生态系统是陆地生态系统的重要组成部分，量化森林对温室气体的储量有利于从生物地球化学角度研究全球变化问题。针对中国森林生态系统承载的温室气体在大尺度上无法有效量化的问题，基于2000与2010年两期土地利用数据和前人的相关研究，通过一个生态系统温室气体值模型，模拟得到中国森林生态系统承载的三大主要温室气体（CO2，CH4，N2O）的量。结果表明：（1）中国森林生态系统的面积从2000年的224.3×106 hm2略增到2010的224.6×106 hm2；其中落叶阔叶林、常绿阔叶林和针叶林的面积减少，而混交林与灌木林的面积增加；（2）对应地，2000和2010年中国森林的温室气体储量分别为154.03和154.37 Pg CO2当量，10年间增加了0.34 Pg CO2当量。其中，常绿针叶林、常绿阔叶林、落叶阔叶林在研究时段内的GHG储量减少，而混交林和灌木林增加。分区来看，温室气体储量增长较多的区域有华北、西北与西南地区，分别增长了0.13 Pg CO2、0.12 Pg CO2与0.15 Pg CO2当量。温室气体储量减少较明显的是东北地区，减少了约0.1 Pg CO2当量。本研究分别用本地化参数和模型自带参数，首次尝试对中国森林生态系统的GHG储量进行了模拟研究，并与他人的研究做了对比分析。研究同时发现，当前的相关研究存在很多不确定性，未来需要多源数据和方法提升精度，而模型模拟是一个重要的手段。 Abstract:Greenhouse gases carried by terrestrial ecosystems are of great significance to the global carbon cycle and climate regulation services. Forests are an important part of terrestrial ecosystems and quantifying the greenhouse gas sequestration potential of forests can analyze global change directly from a biogeochemical perspective. However, greenhouse gases carried by China's forests have not currently be effectively quantified on a large scale. In this study, based on land use data of 2000 and 2010, and previous studies on forest carbon storage, we simulated the sequestration potentials of three main greenhouse gases (CO2, CH4, N2O) in forests in China through a greenhouse gas value model. The results showed that:(1) China's forest area increased slightly from 2.243 million km2 in 2000 to 2.246 million km2 in 2010; among them, areas of deciduous broad-leaved, evergreen broad-leaved, and coniferous forests all decreased, whereas the areas of mixed and shrub forests increased; (2) correspondingly, the sequestration potential of greenhouse gas for China's forests was equivalent to 154.03 and 154.37 Pg CO2 in 2000 and 2010, respectively, increasing by about 0.34 Pg CO2 during our study period. The sequestration potential in evergreen coniferous, evergreen broad-leaved, and deciduous broad-leaved forests decreased during 2000-2010, whereas the sequestration potential in mixed and shrub forests increased. Regarding spatial patterns, sequestration potentials in North, Northwest, and Southwest China all increased largely, with an increase of 0.13, 0.12, and 0.15 Pg CO2, respectively. The sequestration potential in Northeast China was obviously decreased, with a reduction of about 0.1 Pg CO2. This study used the localization parameters and model's own parameters to simulate the sequestration potential of greenhouse gases in China's forests for the first time, and compared our simulated results with those from others research. This study also found that various definitions and data sources on forests had many problems. In the future, it is necessary to refine the model parameters within ecosystems under a unified framework and consider using multi-resource data to improve the accuracy of sequestration potential. Model simulation should be used as an important and effective study method. 参考文献 相似文献 引证文献

模拟穿透雨减少对锐齿栎(Quercus aliena var. acuteserrata)树干液流密度的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 模拟穿透雨减少对锐齿栎(Quercus aliena var. acuteserrata)树干液流密度的影响 DOI: 10.5846/stxb201903060423 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国际竹藤中心基本科研业务费专项基金项目（1632018002，1632018004，1632017016）；国家重点研发计划（2018YFC0507301） Effects of manipulated throughfall reduction on sap flux density of Quercus aliena var. acuteserrata Author: Affiliation: Fund Project: International Bamboo and Rattan Center"s special funds for basic research and operation fees;National Key R&D Program 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:降水格局变化是全球气候变化的重要特征之一，未来气候变化下，较为频繁和严峻的干旱将威胁地球中纬度部分地区的森林，但森林植被如何响应季节性干旱胁迫及其机制尚不清楚。北亚热带-暖温带过渡区分布着以锐齿栎（Quercus aliena var. acuteserrata）为优势树种的落叶阔叶林，研究其水分蒸腾代谢过程对干旱的响应是评估气候变化对过渡区天然落叶阔叶林生态系统水碳影响的关键科学问题。在典型的锐齿栎天然林中通过开展模拟穿透雨减少大型野外实验，采用Granier热扩散式探针技术监测锐齿栎树干液流密度的动态变化，研究了不同径级锐齿栎树干液流密度对模拟干旱的响应规律。结果表明：（1）穿透雨减少对树干液流密度的影响呈现季节变异。在7月份，林内穿透雨减少显著降低了锐齿栎的树干液流密度，但生长季后期的10月份林内穿透雨减少反而使锐齿栎树干液流密度显著升高。（2）不同径级的锐齿栎树干液流密度在生长季内对干旱有不同的响应，特别是小径级的树干液流密度与其他径级有较多的不同。小径级的锐齿栎树干液流密度在5、7月份表现为减雨样地显著小于对照样地，在9、10月份则表现为减雨样地显著大于对照样地。中径级的锐齿栎树干液流密度在5、10月份表现为减雨样地显著大于对照样地，在7月份则表现为减雨样地极显著小于对照样地。大径级的锐齿栎树干液流密度在6、7月份表现为减雨样地显著小于对照样地，在10月份则表现为减雨样地显著大于对照样地。 Abstract:The change in precipitation pattern is one of the characteristics of global climate change. Some regions at mid-latitude might experience more frequent and severe drought. However, it is unclear how the precipitation change will affect the forest vegetation in those regions. Amongst, Quercus aliena var. acuteserrata is the dominant canopy tree species of deciduous broad-leaved forests in the warm temperate zone of middle China. Understanding the evapotranspiration responses of Q. aliena to drought induced by climate change is crucial to elucidate carbon-water coupling process. In order to explore the warm-temperate deciduous broad-leaved forest response to precipitation change, a manipulated throughfall reduction experiment was conducted in Baotianman National Nature Reserve since 2013. The Granier thermal diffusion probe (TDP) was used to measure the dynamic change of sap flux density of Q. aliena. The results showed that the throughfall reduction had significant effects on the sap flux density (Js) during the growing season. Firstly, the throughfall reduction significantly reduced the sap flux density of Q. aliena in July. However, in the late growing season (October), the throughfall reduction increased the sap flux density of Q. aliena significantly. Therefore, the sap flux density of Q. aliena differently responded to the throughfall reduction among months during the growing season. Secondly, the sap flux density of Q. aliena of different tree sizes showed different responses to drought during the growing season, especially the small trees (diameter at breast height, DBH≤21 cm) was different from that of medium (21 cm 参考文献 相似文献 引证文献

Diurnal variation and light response of net ecosystem carbon exchange in a temperate broadleaved deciduous forest at Maoershan, Northeast China

Photosynthetically active radiation (PAR) is a key environmental factor affecting the change of net ecosystem exchange (NEE) during the daytime. However, the coordinate system of PAR measured by horizontal radiometers over sloping terrain does not match that of NEE after tilt-corrected of the ultrasonic anemometer. Using the temperate deciduous broad-leaved forest at the Maoershan site with an average slope of 9° and a azimuth of 296° as a case, we investigated the diurnal variations in NEE and its driving factors in the growing season (May to September) of 2016. We assessed the differences in estimating light response parameters and the explanations of NEE by other environmental factors between the PAR measured by horizontal and slope-parallel radiometers. The results showed that the diurnal change of NEE in each month of the growing season presented a morning-afternoon asymmetrically unimodal curve: the value was negative (net carbon absorption) about 2.5 h after sunrise, reached the peak around 12:00, then approached zero again at two hours before sunset. The daily net uptake maximized in July and minimized in May. During the whole growing season, the time-lag and difference in the PAR measured by the horizontal versus slope-parallel radiometers led to that the PAR values measured by the horizontal radiometer increased photosynthetic quantum yield (α) and daytime respiration rate (Rd) by 13.3% and 11.5%, respectively, and decreased the maximum photosynthetic efficiency (Amax) by 7.7%. The light response curves of NEE were asymmetrical in the morning and afternoon, with Rd and Amax in the afternoon being greater than that in the morning. Weather conditions affected light response parameters: on cloudy days, Amax was higher than that in sunny days, the α and Rd were lower versus those in sunny days for most conditions. However, the monthly Amax and Rd were generally higher for horizontally measured PAR than for slope-parallelly measured PAR, especially for Amax in the cloudy afternoon. The radiometer-orientation affected the explanation of daytime NEE by air temperature (Ta) and vapor pressure deficit (VPD). The correlation of NEE residual based on the slope-parallel radiometer with Ta and VPD (r ranged: 0.013 to 0.197, 0.098 to 0.224) was tighter than that based on the horizontal radiometer (r ranged: 0.082 to 0.219, 0.162 to 0.282) when the negative correlations with Ta for September was excluded. Our results indicated that the measurements of PAR on the inclined terrains could cause errors in the environmental interpretations of NEE. Such findings had implications for the radiometric measurement of mountain vegetation and the reasonable interpretation of carbon exchange in terrestrial ecosystems.

Numerical Analyses of Transport Processes of Bioaerosol Released from a Temperate Deciduous Broad-Leaved Forest

Numerical Analyses of Transport Processes of Bioaerosol Released from a Temperate Deciduous Broad-Leaved Forest

Assessing differences in the response of forest aboveground biomass and composition under climate change in subtropical forest transition zone

The subtropical forest transition zone in southern China is a typical transition zone with high coverage and diverse vegetation. Projected climate change will affect physiological processes of trees, which would consequently alter the forest aboveground biomass (AGB) and composition at broad spatial scales. However, spatially heterogeneous responses may also be shaped by climate change, succession, and harvesting in different forest habitats. The objectives of this study were to assess the changes in subtropical forest AGB and composition in response to climate change, while comparing the responses of two similar forest landscapes: Taihe County (TH) and Longnan County (LN). We used a loose-coupling of PnET-II with LANDIS-II to simulate changes in forest AGB and composition under climate change scenarios (Current climate, RCP2.6, RCP4.5, RCP6.0, and RCP8.5) with harvest disturbances. Our simulation results demonstrated that forest AGB and composition were significantly affected by climate change in both landscapes. Changes in forest AGB was mostly driven by succession and harvest, but climate change also greatly contribute to the variation in AGB of deciduous broad-leaved forests (DBF), and coniferous forests (CF). Moreover, a larger area of LN experienced biomass reduction compared to TH, specifically under the RCP8.5 scenario. Given our estimates of the response in forest AGB and composition under climate change scenarios across different periods, we recommend that the regional forest management should be localized and should consider the effects of climate change through time in their planning schemes.

The composition of the middle Miocene (15 Ma) Namling paleoflora, South Central Tibet, in the context of other Tibetan and Himalayan Floras

Molecular phylogeneticists often find that a diversification of western Chinese plant taxa took place in the Miocene and link this to the Neogene uplift of the Tibetan Plateau. This link is made despite abundant geological evidence showing that a high but topographically complex Tibet already existed in the Paleogene. To evaluate and constrain molecular phylogenetic trees and better understand Asian plant diversification requires accurate systematic assignment of well-dated plant megafossils. Here, as part of an ongoing programme of absolute dating and taxonomic evaluation of fossil floras across southwestern China and the Himalaya, we present a new and expanded systematic treatment of the late Miocene leaf flora from the Gazhacun Formation near the village of Wang b'dui in Namling County, central southern Tibet. This flora, whose age (15 Ma) and paleoelevation (~5 km) are well constrained, comprises 9 families, 13 genera and 25 species (including 22 new species). The paleoflora represents a typical boreal temperate mostly deciduous broad-leaved forest attesting to a cool humid climate. At the paleolatitude of the site, <28 °N, this is compatible with the high elevation (4700–5200 m) for this part of Tibet quantified by both leaf physiognomy and isotopic analyses. Plant fossil evidence also witnesses a much wetter Tibetan upland environment before a rising Himalaya obstructed northward-moving moist air from the Indian Ocean.