Mixed Broadleaf Forest Research Articles

Soil aggregate characteristics and stability of soil carbon stocks in a Pinus tabulaeformis plantation

Pinus tabulaeformis has been widely planted in order to conserve soil and water and improve the ecological environment in China. This study aimed to unravel how soil aggregates and soil carbon (C) stock stability of a P. tabulaeformis plantation change after 60 years of natural development and was performed in Vitex negundo var. heterophylla and Ziziphus jujuba var. spinosa shrub (shrub), a P. tabulaeformis forest (pine), and a coniferous broadleaf P. tabulaeformis mixed forest (pine-oak). Afforestation increased the stability of soil aggregates in the 0–10 cm soil layer but resulted in a decrease in the 10–20 cm soil layer. However, the presence of deciduous broadleaf species in the pine plantation improved the stability of soil aggregates. The total soil C stock was increased by afforestation, especially in the pine-oak forest, where it reached a significant level. The mineral soil C stock in the shrub stand was higher than that in pine and lower than that in pine-oak forests, but the C fractions had a different change. Afforestation increased the C fraction of macroaggregates in the 0–10 cm soil layer but decreased it in the 10–20 cm soil layer. This result suggested that afforestation could improve soil C stabilization in deeper soil. However, the pine-oak forest had a higher C fraction of macroaggregates than the pine forest in the 10–20 cm soil layer, indicating that soil C stabilization of the P. tabulaeformis plantation decreased when deciduous broadleaf species were present and thus formed the coniferous broadleaf mixed forest.

Forest-type shift and subsequent intensive management affected soil organic carbon and microbial community in southeastern China

In this study, we investigated the effect of forest types changes (from coniferous and broadleaf mixed forest (CBMF) to plantation forests of bamboo (Phyllostachys pubescens forest, MBF) and hickory (Carya cathayensis forest, CHF)) combined with intensive management on soil organic carbon (SOC) and microbial community structure, using the 13C-nuclear magnetic resonance (NMR) and phospholipid fatty acid (PLFA). The results indicated that soil organic carbon significantly decreased by 30.7 and 28.5% in MBF and CHF, respectively. The aromatic C and aromaticity also significantly decreased in MBF and CHF (P 0.05). Significant changes of the soil microbial community were found after the forest type changed from CBMF to MBF and CHF. Total soil microbial PLFAs, soil bacteria PLFAs, fungus PLFAs, actinobacteria PLFAs, arbuscular mycorrhizal fungi PLFAs and protozoan PLFAs ranked as follows: CBMF > CHF > MBF (P CHF (0.66) > CBMF (0.49) (P CHF > MBF, P < 0.05). The converting CBMF into MBF and CHF combined with fertilization and tillage significantly changed the SOC and microbial community. Therefore, necessary measures should be taken to improve the SOC and soil fertility in the MBF and CHF.

Effect of carbon and nitrogen addition on nitrous oxide and carbon dioxide fluxes from thawing forest soils

AbstractPacked soil-core incubation experiments were done to study the effects of carbon (glucose, 6.4 g C m−2) and nitrogen (NH4Cl and KNO3, 4.5 g N m−2) addition on nitrous oxide (N2O) and carbon dioxide (CO2) fluxes during thawing of frozen soils under two forest stands (broadleaf and Korean pine mixed forest and white birch forest) with two moisture levels (55 and 80% water-filled pore space). With increasing soil moisture, the magnitude and longevity of the flush N2O flux from forest soils was enhanced during the early period of thawing, which was accompanied by great NO3−-N consumption. Without N addition, the glucose-induced cumulative CO2fluxes ranged from 9.61 to 13.49 g CO2-C m−2, which was larger than the dose of carbon added as glucose. The single addition of glucose increased microbial biomass carbon but slightly affected soil dissolved organic carbon pool. Thus, the extra carbon released upon addition of glucose can result from the decomposition of soil native organic carbon. The glucose-induced N2O and CO2fluxes were both significantly correlated to the glucose-induced total N and dissolved organic carbon pools and influenced singly and interactively by soil moisture and KNO3addition. The interactive effects of glucose and nitrogen inputs on N2O and CO2fluxes from forest soils after frost depended on N sources, soil moisture, and vegetation types.

Biodiversity indexes in relation to soil properties in upland fir forests (Abietetum albae)

Abstract The aim of this study was to present the relationship between soil properties and biodiversity indexes in upland fir (Abies alba) forest associations (Abietetum albae). Our study was conducted in six areas representing the growth conditions of upland fir forests and the research plots were located in the Roztoczański and Świętokrzyski National Parks as well as Przedbórz, Radomsko, Piotrków and Janów lubelski Forest District. on every plot, the topography was described, soil cores were examined and samples for laboratory analysis were taken. the following characteristics were determined for the soil samples: ph, c, n, ca, Mg, na and K content, particle size, exchangeable acidity, aluminum content and hydrolytic acidity. additionally, enzyme activity in the soil samples (urease and dehydrogenase) was measured. in each test area, the stand characteristics were measured (diameter at breast height and height), floristic characteristics were described and the biodiversity indexes (Shannon, Simpson and Margalef indexes) were calculated. Different soil types (gleysols, Brunic arenosols, gleyic Podzols and hyperdistric cambisols) were recorded for the investigated forest stands and the soils were categorized according to soil texture, c content, enzyme activity and different humus types (moder-mor, moder, moder-mull). the upland mixed coniferous forest sites were characterized by lower biodiversity indexes (2.6 shannon index; 0.72 simpson index; 4.9 Margalef index) while the upland mixed broadleaf forest sites showed higher indexes (3.3 Shannon index; 0.87 Simpson index; 9.4 Margalef index). The site index obtained for the fir stands confirmed these results.

Utilization of Landsat data to quantify land-use and land-cover changes related to oil and gas activities in West-Central Alberta from 2005 to 2013

Land use and land cover (LULC) change detection associated with oil and gas activities plays an important role in effective sustainable management practices, compliance monitoring, and reclamation assessment. In this study, a mapping methodology is presented for quantifying pre- and post-disturbance LULC types with annual Landsat Best-Available-Pixel multispectral data from 2005 to 2013. Annual LULC and land disturbance maps were produced for one of the major conventional oil and gas production areas in West-Central Alberta with an accuracy of 78% and 87%, respectively. The highest rate of vegetation loss (178 km2/year) was observed in coniferous forest compared to broadleaf forest, mixed forest, and native vegetation. Integration of ancillary oil and gas geospatial data with annual land disturbances indicated that less than 20% of the total land disturbances were attributable to oil and gas activities. In 2013, approximately 44% of oil and gas disturbances from 2005 to 2013 showed evidence of vegetation recovery. In the future, geospatial data related to wildfire, logging activities, insect defoliation, and other natural and anthropogenic factors can be integrated to quantify other causes of land disturbances.

Delineating Individual Tree Crowns in an Uneven-Aged, Mixed Broadleaf Forest Using Multispectral Watershed Segmentation and Multiscale Fitting

Delineating individual tree crowns (ITCs) in high-spatial-resolution images can help to improve forest inventory and management. However, single-band watershed segmentation methods often fail to delineate broadleaf species, particularly in uneven-aged stands when a single-scale parameter is used to fit segments to reference crowns of different sizes. In this study, we present multispectral watershed segmentation and multiscale fitting method for ITC delineation, and the method involves two steps: 1) multispectral watershed segmentation to produce multiscale segmentation for subsequent fitting, which takes full advantage of boundary information contained in the spectral contrast of multiple bands; and 2) multiscale fitting to identify optimal parameters to best fit each ITC, rather than selecting a single parameter value based on its overall fit to the image as a whole. We evaluate the effectiveness of the proposed method using two multispectral images from a mixed broadleaf forest in Central Ontario, Canada. Our results show that multispectral watershed segmentation at multiple spatial scales produces ITC maps of higher quality than the commonly used multiresolution segmentation method. The automated multiscale fitting produces ITC maps of higher quality than the best single-scale segmentation.

Warm-cold colonization: response of oaks to uplift of the Himalaya-Hengduan Mountains.

Clarifying the relationship between distribution patterns of organisms and geological events is critical to understanding the impact of environmental changes on organismal evolution. Quercus sect. Heterobalanus is now distributed across the Himalaya-Hengduan Mountains (HHM) and warm lowland in East China, yet how the distribution patterns of this group changed in response to the HHM uplift remains largely unknown. This study examines the effect of tectonic events in the HHM region on the oaks, providing a biological perspective on the geological history of this region. Fifty-six populations of Quercus sect. Heterobalanus were genotyped using four chloroplast DNA regions and nine nuclear simple sequence repeat loci to assess population structure and diversity, supplemented by molecular dating and ancestral area reconstructions. The underlying demographic dynamics were compared using ecological niche models of the species distributions during the last glacial maximum and the present. These analyses illustrate that Quercus sect. Heterobalanus diversified as the HHM uplifted and climatic cooling during the mid-Miocene, colonizing the cold habitats from warm broadleaf mixed forests. Lineages in cold highlands and warm lowlands have diverged as a consequence of local adaptation to diverging climates since the late Miocene. Our results suggest that continuous uplift of the HHM in the late Miocene to early Pliocene accompanied by simultaneous cooling triggered the differentiation of oaks. The biogeography of Quercus sect. Heterobalanus illuminates the geological events responsible for the modern-day HHM.

Habitat filtering and exclusion of weak competitors jointly explain fern species assemblage along a light and water gradient

Fern species are an important component of the diversity of forest plant communities, but very little is known about how fern communities assemble in different environments. In this study, we use multiple trait-based tests to examine the relationships between several key eco-physiological traits which are direct indicators of shade and drought tolerance, and the abundance of fern species in pine forest (PF), pine and mixed broad leaf forest (PMBF) and matured broad leaf forest (MBF) in southern China. These forests are characterized by decreasing light but increasing water availability during succession, and the fern communities correspondingly differ in species composition. We tested community assembly using functional trait distributions and found that habitat filtering and exclusion of weak competitive traits among coexisting species jointly explain fern shade tolerance as measured by photosynthetic capacity (PR), photosynthetic nutrient efficiency (PNUE and PPUE) and water use efficiency as measured by carbon isotope ratio (CIR), and constitute important determinants of fern community assembly in all three forests. These observed fern plant strategies are consistent with known responses of other plant taxa such as flowering plants in similar successional environments and illustrate the value of functional trait based analyses to study community assembly.

Carbon storage by Mediterranean vegetation developing inside a protected area

Carbon (C) storage and its dynamics in vegetation and soil are important for predicting how terrestrial ecosystem carbon pools may change as climate and land use change in the next future. In this context, the organic fraction of the C stored in the above-ground biomass (CA), below-ground biomass (CB), deadwood mass (CD), litter (CL) and soil (CS) was estimated for different plant land-cover categories: forests (i.e. low and high Mediterranean maquis, Quercus ilex evergreen forest, Quercus suber evergreen forest, Pinus pinea plantations, broadleaf mixed forest, Eucalyptus globulus plantations), sand dune vegetation, grasslands and croplands developing inside the Castelporziano Presidential Estate (Italy). The total C storage inside the Presidential Estate resulted in 2434 Mg C ha−1 (sum of all the carbon pools) with Quercus ilex evergreen forest having the highest contribution (by 22%) and sand dune vegetation the lowest (0.01%). The five C pools differently contributed to the total carbon storage in the Estate: CS gave the highest contribution (48%), followed by CA (31%) and CB (10%). CD and CL contributed to a lesser extent (both 6%) to total carbon storage.

Breeding system of Anemone shikokiana and the influential factors of fruit-setting ratio in different habitats

Anemone shikokiana (Makino) Makino is a rare perennial herb distributed only in China and Japan in restricted patches of two different habitats: the shrubs of mountaintop and the conifer and broadleaf mixed forest. Our data showed that the fruit-setting ratio is much lower in the latter than in the former. Given that the reproductive strategy is very crucial for fruit-setting, to reveal the main reasons that influence the fruit-setting ratio, breeding system must be known. Therefore, firstly, P/O and OCI were analyzed and results showed that breeding system of A. shikokiana was self-compatible and mainly outcrossed. Secondly, controlled pollination tests were carried out showing that neither apomixes nor wind pollination occurred. Further results on the type of the breeding system confirmed that A. shikokiana was self-compatible and mainly outcrossed by insects. Lastly, diameters of flowers and frequency of pollinators in two habitats were compared. Results showed that flowers were bigger and frequency of pollinators were higher in shrubs of mountaintop than those in conifer and broadleaf mixed forest, while numbers of pollens and ovaries had little difference. Thus, the overall analysis of the results indicates that the paucity of insect pollinators is the most important reason for the fruit-setting ratio of A. shikokiana lower in the conifer and broadleaf mixed forest than in the shrubs of mountaintop; however, such an implication needs to be further verified with additional work.

An integrated UAV-borne lidar system for 3D habitat mapping in three forest ecosystems across China

ABSTRACTIn recent decades, global biodiversity has gradually diminished due to the increasing pressure from anthropogenic activities and climatic change. Accurate estimations of spatially continuous three-dimensional (3D) vegetation structures and terrain information are prerequisites for biodiversity studies, which are usually unavailable in current ecosystem-wide studies. Although the airborne lidar technique has been successfully used for mapping 3D vegetation structures at landscape and regional scales, the relatively high cost of airborne lidar flight mission has significantly limited its applications. The unmanned aerial vehicle (UAV) provides an alternative platform for lidar data acquisition, which can largely lower the cost and provide denser lidar points compared with airborne lidar. In this study, we implemented a low-cost UAV-borne lidar system, including both a hardware system and a software system, to collect and process lidar data for biodiversity studies. The implemented UAV-borne lidar system was tested in three different ecosystems across China, including a needleleaf–broadleaf mixed forest, an evergreen broadleaf forest, and a mangrove forest. Various 3D vegetation structure parameters (e.g. canopy height model, canopy cover, leaf area index, aboveground biomass) were derived from the UAV-borne lidar data. The results show that the implemented UAV-borne lidar system can generate very high resolution 3D terrain and vegetation information. The developed UAV-based hardware and software systems provide a turn-key solution for the use of UAV-borne lidar data on biodiversity studies.

Patterns of vegetation composition across levels of canopy disturbance in temperate forests of west Himalaya, India

Abstract This study analyses the impacts of canopy disturbance on vegetation compositional attributes of two characteristic temperate forests (i.e., mixed broad-leaf and banj-oak forests) in west Himalayan part of India. Following the standard approaches, quantitative information on compositional attributes of forest vegetation was generated and analyzed. Considerable changes in these attributes were revealed across different levels of canopy disturbance in both forests. In particular, tree density and total basal area (TBA) exhibited significant decline from undegraded to degraded stands. Among others, seedling and sapling density of mixed broad-leaf forest was affected adversely by increased level of canopy disturbance. However, herb density in this forest increased significantly with increasing levels of disturbance; the same was not true for banj-oak forest. A significant decline in relative frequency and density of native herbaceous species was apparent towards degraded stands, implying that the disturbed sites in both forests created an opportunity for the establishment and proliferation of non-natives. However, with significant increase in relative density of non-native herbs, the degraded stands of banj-oak forest emerged as critically vulnerable to non-native proliferation. The patterns of tree size class distribution in both forests also exhibited certain trends across canopy disturbance, which suggested possible future changes in composition. In particular, the patterns of common tree associates (i.e., Myrica esculenta and Rhododendron arboreum) in banj-oak forest and Pinus roxburghii in mixed broad-leaf forest were indicative of likely compositional changes in near future. The study concludes that: (i) compositional attributes of both mixed broad-leaf and banj-oak forests were sensitive to increasing levels of canopy disturbance, (ii) mixed broad-leaf forest exhibited greater sensitivity to canopy disturbance at recruitment levels, (iii) increased canopy disturbance led to establishment and proliferation of non-native species in the herbaceous layer of both forests, and (iv) banj-oak forest exhibited high vulnerability to non-native proliferation at degraded stage.

Research progress of phylogeographic studies of plant species in temperate coniferous and broadleaf mixed forests in Northeastern China

Research progress of phylogeographic studies of plant species in temperate coniferous and broadleaf mixed forests in Northeastern China

川西亚高山不同森林生态系统碳氮储量及其分配格局

PDF HTML阅读 XML下载 导出引用 引用提醒 川西亚高山不同森林生态系统碳氮储量及其分配格局 DOI: 10.5846/stxb201604150688 作者: 作者单位: 中国林业科学研究院森林生态环境与保护研究所,中国林业科学研究院森林生态环境与保护研究所,阿坝州林业科学技术研究所,阿坝州林业科学技术研究所,中国林业科学研究院,中国林业科学研究院森林生态环境与保护研究所;南京林业大学南方现代林业协同创新中心 作者简介: 通讯作者: 中图分类号: 基金项目: 中央级公益性科研院所基本科研业务费专项资金资助项目（CAFYBB2014MA004）；国家“十二五”科技支撑计划课题资助项目（2012BAD22B0102） Carbon and nitrogen storage and distribution in different forest ecosystems in the subalpine of western Sichuan Author: Affiliation: Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry,,,,,Chinese Academy of Forestry 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:森林采伐和恢复是影响森林碳氮储量的重要因素。以川西亚高山岷江冷杉原始林、粗枝云杉阔叶林、天然次生林和粗枝云杉人工林为研究对象，采用样地调查和生物量实测的方法，研究了不同森林生态系统各组分碳、氮储量及其分配特征。结果表明岷江冷杉原始林、粗枝云杉阔叶林、天然次生林和粗枝云杉人工林生态系统碳储量分别为611.18、252.31、363.07 tC/hm2和239.06 tC/hm2；氮储量分别为16.44、12.11、15.48 tN/hm2和8.92 tN/hm2。恢复林分与原始林碳储量在土壤-植被的分配格局发生了变化，而氮储量未发生变化。岷江冷杉原始林以植被碳储量为主，恢复林分以土壤为主，氮储量均以土壤为主。乔木层碳储量分别占生态系统总储量的56.65%、17.63%、13.57%和22.05%，土壤层（0-80 cm）分别占32.03%、69.87%、76.20%和72.12%；土壤层氮储量占生态系统总储量的76.80%-92.58%。植物残体碳氮储量分别占生态系统总储量的4.40%-9.83%和2.94%-7.08%，林下植被所占比例最小。空间格局上，岷江冷杉原始林植被部分具有较高的碳储量，应进行保护。3种恢复林分具有较高的碳汇潜力，且地上/地下碳储量较低，表明其碳汇潜力尤其表现在地上部分。天然次生林利于土壤有机碳的积累，而人工林乔木层碳储量较高。 Abstract:Carbon (C) and nitrogen (N) are major constituents of plant and soil organic matter, and play a fundamental role in nutrient cycling, plant growth, and ecological function. Biogeochemical cycling of C and N has attracted much attention because of oxides released from ecosystems to the atmosphere are important factors driving global warming, and N availability limits plant productivity. Forests are the main C pool in terrestrial ecosystems and have a substantial influence on the global C cycle and atmosphere carbon dioxide (CO2) concentrations. However, C and N storage in forests vary greatly because of differences in forest type, forest age, regional climate, and soil conditions. Forest harvest and restoration lead to different forest types and structures, which are important factors in decreasing and increasing C and N stocks. As such, research on C and N storage in each component of the forest ecosystems will be beneficial in the evaluation of the impact of different management regimes on C and N pools. The subalpine forest in western Sichuan is important for water resource conservation and is an ecological barrier in the upper reaches of the Yangtze River. Historically, large area of fir were cut down, and the area was restored with three different forest types (including plantation, natural secondary forest, forest under mixed influence of artificial and natural sources), which have different species composition, including the presence of spruce; the change in C and N stores is still unknown. More studies are needed to calculate C and N pools in this region because of its varying topography, community diversity, and complex ecosystems. In this study, C and N stores in different forest ecosystems of Abies faxoniana primary forest (AF), Picea asperata broadleaf mixed forest (PB), natural secondary forest (NS), and Picea asperata plantation forest (PA) in the subalpine of western Sichuan were quantified. The results showed that ecosystem organic carbon of AF, PB, NS, and PA was 611.18, 252.31, 363.07 tC/hm2, and 239.06 tC/hm2, whereas nitrogen storage was 16.44, 12.11, 15.48 tN/hm2, and 8.92 tN/hm2. Distribution patterns of carbon storage between soil and plants, not nitrogen storage, had changed between primary and restored forests. Carbon storage of primary and restored forests was dominated by vegetation and soil, respectively, whereas nitrogen storage was dominated by soil. Carbon storage of the tree layer accounted for 56.65%, 17.63%, 13.57%, and 22.05% of ecosystem total storage, soil layer (0-80 cm) occupied 32.03%, 69.87%, 76.20%, and 72.12% for carbon storage and 76.80%-92.58% for nitrogen storage. The proportion of carbon and nitrogen storage of woody debris and litter were 4.40-9.83% and 2.94-7.08%, respectively, which were higher than that of the understory vegetation. Abies faxoniana primary forest had high carbon storage, and it is especially important to protect. Three kinds of restored forests had high carbon sequestration potential, especially above-ground indicated by low above- and under-ground carbon storage rations. Natural secondary forest was beneficial to soil carbon accumulation and plantation forest to tree carbon storage. 参考文献 相似文献 引证文献

HIGH DENSITIES OF CERVIDAE EFFECT TO FOREST REGENERATION IN MIXED BROADLEAF FOREST IN SOUTH PART OF LITHUANIA

The abundance of Cervidae species is increasing in Lithuania as well as in thewhole Baltic region. High densities of forest ruminants: Moose (Alces alces), Reddeer (Cervus elaphus), Roe deer (Capreolus capreolus), Fallow deer (Dama dama)and European bison (Bison bonasus) cause a significant damage both to naturalforest regeneration and afforestation. Strong negative impact on forest regenerationlead to increased costs of forest regeneration, formation and maintenance. Thus, thebalance among intensive silviculture and big game management must be found forsustainable use of environment recourses. In our study, we observed the influenceof cervids density increment to natural forest regeneration in mixed broadleafforest, which is located near the Zuvintas strict reserve, and in landscape point ofview connected with other forest arrays by natural migration corridors. We foundthat natural regenerated forest understory is hardly damaged as well as culturalforest plantations. Thus, hunting pressure in our research area is obviously too lowand the current abundance of wild ruminants will not allow the economicallyeffective intensive silviculture. After investigation we found a steady Cervidaeabundance, not exceeding the highest optimal densities. Cervid winter pasturequality is relatively good – economically and browsing very intensively did noteffect ecologically important tree species regeneration in forest understory.However, damage degree to forest regeneration in our observed stands was veryhigh. Natural as well as artificial forest regeneration is rather difficult, thus cerviddensities should be reduced of expensive protection tools should be implemented inforest regeneration stands.

Interspecific and Intraspecific Variation in Functional Traits of Subtropical Evergreen and Deciduous Broadleaved Mixed Forests in Karst Topography, Guilin, Southwest China

Interspecific variation in plant functional traits is the basis of species coexistence in natural ecosystems. However, intraspecific variation is extremely important to community assemblage as well. Here, we quantify leaf trait variation within and across 32 dominant shrub species within two different leaf forms (16 evergreen species and 16 deciduous species) in subtropical evergreen and deciduous broadleaf mixed forest in the Karst topography of Guilin, southwest China. Results showed that leaf area (LA) and leaf thickness (LT) of evergreen species were significantly lower than those of deciduous species, whereas specific leaf areas (SLA) and leaf dry matter content (LDMC) showed the opposite pattern. For SLA and LA, the majority variance was found among species (50.82% vs. 65.01%) and little was found within species (22.98% vs. 27.89%), whereas the largest variation was within species (44.87% vs. 48.2%) with little among species (40.73% vs. 43%) for LDMC and LT. The large variability of LDMC and LT within species may reflect niche differentiation and the importance of intraspecific variation on species coexistence. Our results will help design conservation strategies for this unique subtropical evergreen-deciduous broadleaved forest ecosystem.

Reclamation patterns vary carbon sequestration by trees and soils in an opencast coal mine, China

Reforestation is often recommended for ecological restoration in mining areas because of tree's high stand-level productivity and satisfied carbon (C) and other nutrient sequestration objectives. However, the C sequestration efficiency of different plantation patterns or different tree species is rarely understood. In order to get insight of the C sequestration efficiency by trees and soils of different reclamation patterns in Pingshuo opencast coal mine, Shanxi Province, China, three different reclamation patterns (developed for 17years) at three permanent fixed plots, broadleaf mixed forest: R. pseudoacacia-U. pumila-A. altissima (Plot code: BM), broadleaf conifer mixed forest: R. pseudoacacia-P. tabulaeformis (Plot code: BC) and broadleaf monoculture forest: R. pseudoacacia (Plot code: BR), were selected and investigated. The results showed that tree volumes and biomass differed significantly after 17years' succession, from 21.58m3 and 36.02Mgha−1 of the broadleaf monoculture forest (BR) to 37.20m3 and 48.73Mgha−1 of broadleaf conifer mixed forest (BC). Accordingly, tree C and litter C were observed higher in BC (24.37 and 2.26Mgha−1) than BM (19.25 and 1.15Mgha−1) and BR (18.01 and 1.31Mgha−1). Herb C, however, was observed lower in BC (0.02Mgha−1) than BR (0.25Mgha−1) and BM (0.24Mgha−1). C sequestrated in soil organic matter varied in the order: BC (172.16Mgha−1)>BM (73.79Mgha−1)>BR (51.59Mgha−1) and the top layer (0-20cm) C contributed a large portion (varied from 37% in BC to 53% in BM) of the total soil C. Consequently, BC sequestrated the highest total C (198.81Mgha−1) by plant, litter and soil, followed by BM (94.43Mgha−1) and BR (71.16Mgha−1). In regard to the total C distribution, a major portion of the total C consisted of soil C (varied from 72.49% in BR to 86.60% in BC). Overall, this study indicated that mixed forest facilitated sequestrating more C than pure forest, and the broadleaf conifer mixed forest: R. pseudoacacia-P. tabulaeformis not only accumulated more plant biomass but also accelerated the soil C sequestration which may be suggested as the more suitable pattern for the opencast coal mine reclamation in the region of eastern Loess Plateau of China.

Analysis of plant remains at the Neolithic Yangjia Site, Wuxi City, Jiangsu Province (East China)

According to archaeological investigation and preliminary excavation, the Yangjia Site, located in the northern Taihu Lake region, at Wuxi City, Jiangsu Province, is a Neolithic archaeological site dominated by cultural remains attributed to the late Majiabang Culture (6270–5920 cal. a BP). Here a systematic archaeobotanical study was conducted to investigate vegetation landscape, environmental characteristics and rice agriculture in the prehistoric northern Taihu Lake area. The abundance, frequency and standard density of charred rice were the highest of all of the remains of the seed plants unearthed. In addition, a variety of wetland weeds, such as Haloragaceae, Cyperaceae, Carex sp., and Oxalis corniculata, were found. Pollen and phytoliths recorded that the evergreen-deciduous broadleaf mixed forest (represented by Quercus and Castanopsis) tends to decrease, while Poaceae was the most significant of the terrestrial herbs, water area expanded and water activities strengthened, indicating generally warm and humid conditions at the Yangjia Site during the late Majiabang Culture. All indicators of pollen, phytolith and macro-plant remains suggest that wild rice should be once distributed at or around the site before human occupation, after which rice agriculture progressed rapidly during the late Majiabang Culture.

Protected areas may not effectively support conservation of endangered forest plants under climate change

Protected areas (PAs) play an important role in the conservation of valuable forest resources, and an increasing number of areas are being designated as PAs worldwide. However, climate change could drive endangered forest plants out of PAs, and impact the function of PAs to conserve endangered forest plants. Hence, it is necessary for conservation biologists to put forward a simple method to evaluate the ability of PAs to conserve endangered forest plants. Here, we studied 61 endangered forest plants from three ecoregions in China. We applied species distribution modeling to project suitable habitats of endangered forest plants, and used geographical information system to compute whether PAs could support the conservation of endangered forest plants. With climate change caused by increasing gas concentration, the overall ability of PAs to support the conservation of endangered forest plants will likely decrease compared to the conservation needs of ecoregions. We found that PAs have varying abilities to conserve endangered forest plants in different ecoregions. For temperate broadleaf mixed forests and tropical and subtropical moist broadleaf forests, we found that climate change will decrease the PAs’ ability to support the conservation of endangered forest plants effectively in the existing forest landscape. In contrast, we found that temperate conifer forests will likely remain effective. Using this information, we proposed the conservation plans for different ecoregions under climate change. For PAs with limited ability to support the conservation of endangered forest plants in an ecoregion, we recommend expanding the areas of forests and PAs based on the suitable habitats of the endangered forest plants. For PAs with stable ability to support the conservation of endangered forest plants in an ecoregion, we recommend expanding the conservation areas in PAs.

Growth responses of broad-leaf and Korean pine mixed forests at different successional stages to climate change in the Shengshan Nature Reserve of Heilongjiang Province, China

Aims This research examined the different response of tree growth to climate change at the early, middle, late and matured successional stages of Korean pine (Pinus koraiensis) and broadleaf mixed forest. Methods This research used dendroecological methods to analyze radial growth at different successional stages of Korean pine forests in response to climatic change in the Shengshan Nature Reserve of Heilongjiang. Important findings Chronology statistics indicated that the sensitivity of radial growth to inter-annual climate variability decreased from early to later successional stage. Meanwhile, the influence of some climate indices to radial growth also changed during the successional process. Radial growth of matured forest was positively re- lated to mean monthly temperature in June and December of previous year, revealing an obvious lag of temperature. The ring-width of matured forest had a negative correlation with mean monthly temperature but a positive correlation with monthly precipitation in June of current year, reflecting the limiting role of growing sea- son water availability. However, these limiting effects gradually disappeared towards the earlier stages of forest succession. On the contrary, the growth of early successional forest was negatively correlated to precipitation in June of previous year, and this effect disappeared towards the later successional stages. These differences revealed increased demand of water by dominant species from early to later successional stages. A moving correlation analysis showed that the increased warming and drying climate in the research area had both positive and negative influences on radial growth of each forest type. Earlier successional forests did not show clear long-term growth