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Gao R.M.,Shanxi Agricultural University | Shi X.D.,Shanxi Agricultural University | Guo Y.D.,Shanxi Agricultural University | Fan L.Y.,Shanxi Academy of Forestry science
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2015

Larix principis-rupprechtii is one of dominant deciduous coniferous tree species in subalpine temperate forests of North China. It plays significant roles in water conservation, ecotourism and biodiversity maintenance in its distributional areas. It is also one of major economic tree species in this region due to its fast growth and good-quality timber. Previous studies suggest that L. principis-rupprechtii experiences natural regeneration failure, as indicated by low proportion of saplings and seedlings in natural conditions. The failure of regeneration is a threat to persistence of L. principis-rupprechtii forests in its distributional areas. However, the causes of natural regeneration failure are still poorly understood. This study was to examine whether the natural regeneration failure of this species was driven by seed limitation. We investigated seed rain, soil seed bank and seedling regeneration in five typical larch stand types, i.e., pure L. principis-rupprechtii stand, L. rincipis-rupprechtii + Betula platyphylla stand, L. principis-rupprechtii + Populus davidiana stand, L. principis-rupprechtii + P. davidiana + B. platyphylla stand, L. principis-rupprechtii + Picea wilsonii stand. Fifteen 50 cm × 50 cm seed traps were deployed in each plot for seed rain collecting. For each plot, 15 quadrats of 20 cm×20 cm with 10cm depth and 50 quadrats of 1 m × 1 m were examined nearby seed traps for soil seed bank and recruitment survey, respectively. We found that most of seeds were dispersed from September to October. In 2011, which was a seed year of L. principis-rupprechtii, seed production was amounted to (961.93±377.40) seeds/m2, (89.31±16.13)% of which was full seeds. In 2012, a common seed year, both seed production and full seeds proportion were lower than those in previous year, with (252.73±115.12) seeds/m2 and (36.04±4.26)%, respectively. Furthermore, seed rain of L. principis-rupprechtii was mainly from the surrounding mother trees. Seed rain densities of pure L. principis-rupprechtii stand and L. principis-rupprechtii + P. wilsonii stand were higher than those of the other three stand types, which were mixed with broad-leave trees. Thirdly, soil seed bank of L. principis-rupprechtii was mainly from the seed rain that produced in previous year. Seed bank in April of 2012 was (695.18±297.23) seeds/m2, accounting for (76.05±13.79)% of seed rain in autumn of 2011. More than 85% of seeds were found in the litter layer. About (59.73±9.56)% of the seed bank was full seeds. There were (78.98±24.76) seeds/m2 remained viable to germinate before natural regeneration, accounting for (19.02±5.00)% of full seeds in soil seed bank. The germination capacity decreased with time being in forest floor, hence, forming a short-term persistent soil seed bank for L. principis-rupprechtii. Lastly, the emergence of seedlings uncoupled with the seed storage. The frequency of seedling emergence was 1.6%. Seedlings could hardly survive understory. Collectively, this study demonstrates that seed source, especially in seed year, is not the limiting factor for the poor natural regeneration of L. principis-rupprechtii. Our study suggests that further studies should be carried out to examine the detrimental or limiting factors, such as effects of soil moisture and litter, for the natural regeneration failure of the species. © 2015, Ecological Society of China. All rights reserved. Source

Liu X.P.,CAS Institute of Genetics and Developmental Biology | Zhang W.J.,CAS Institute of Genetics and Developmental Biology | Wang X.Y.,CAS Institute of Genetics and Developmental Biology | Cai Y.J.,CAS Chengdu Institute of Mountain Hazards and Environment | Chang J.G.,Shanxi Academy of Forestry science
Tree Physiology | Year: 2015

During periods of water deficit, growing roots may shrink, retaining only partial contact with the soil. In this study, known mathematical models were used to calculate the root-soil air gap and water flow resistance at the soil-root interface, respectively, of Robinia pseudoacacia L. under different water conditions. Using a digital camera, the root-soil air gap of R. pseudoacacia was investigated in a root growth chamber; this root-soil air gap and the model-inferred water flow resistance at the soil-root interface were compared with predictions based on a separate outdoor experiment. The results indicated progressively greater root shrinkage and loss of root-soil contact with decreasing soil water potential. The average widths of the root-soil air gap for R. pseudoacacia in open fields and in the root growth chamber were 0.24 and 0.39 mm, respectively. The resistance to water flow at the soil-root interface in both environments increased with decreasing soil water potential. Stepwise regression analysis demonstrated that soil water potential and soil temperature were the best predictors of variation in the root-soil air gap. A combination of soil water potential, soil temperature, root-air water potential difference and soil-root water potential difference best predicted the resistance to water flow at the soil-root interface. © 2015 The Author 2015. Published by Oxford University Press. All rights reserved. Source

Zhao R.-W.,Beijing Forestry University | Zhang J.-J.,Beijing Forestry University | Chen B.-Q.,Beijing Forestry University | Wang Y.-Q.,Beijing Forestry University | And 3 more authors.
Beijing Linye Daxue Xuebao/Journal of Beijing Forestry University | Year: 2016

We investigated the effects of different soil surface mulching measures, i. e., grass and plastic film, on evaporation, soil moisture content and the first-year survival rate of afforestation, in order to select appropriate mulching measures for afforestation in semi-arid and steep slope areas in the Caijiachuan Watershed, Jixian County, Shanxi Province. It was found that the cumulative evaporations for areas mulched with grass in soil, grass and plastic film on the surface were reduced by 20.96,11.5 and 5.64 mm, respectively, compared with areas without mulching treatment, in the early 20 days after afforestation. From April to June of 2015, the reduction of soil moisture content of areas that received different mulching treatments was ranked as non-mulching > grass mulching on the surface > plastic film mulching on the surface > grass mulching in soil. However, the increase in soil moisture content of areas that received different mulching treatments from June to August was ranked as grass mulching in soil > grass mulching on the surface > plastic film mulching on the surface > non-mulching. From August to October, the reduction of soil moisture content of areas that received different mulching treatments was ranked in the same order as that from April to June. After the growing season (April to October),the soil particle density in the area that received non-mulching, mulching of plastic film and grass on the surface and mulching of grass in soil treatments decreased by 0.79%,1.59%,3.17% and 9.26%,and the total porosity of them increased by 0.04%,0.31%,1.57% and 3.58%, respectively. The average heights of trees planted in the soils that received mulching of plastic film and grass on the surface and mulching of grass in soil were, respectively, 2.52,3.11 and 3.44 times higher, the mass growths of new branches were 0.50,0.65 and 0.90 times larger, and the first-year survival rates were increased by 10.3%, 6.8% and 12.9%, respectively, compared with those of the trees planted in soils that received non- mulching treatment. It can be concluded from the comparison that, the treatment of grass mulching in soil is helpful in improving soil moisture conditions and increasing the first-year survival rate of afforestation in semi-arid and steep slope areas in the Loess Plateau area of western Shanxi Province. © 2016, Editorial Department of Journal of Beijing Forestry University. All right reserved. Source

Liu X.,Chinese Academy of Sciences | Zhang W.,Chinese Academy of Sciences | Zhang B.,Chinese Academy of Sciences | Yang Q.,Changjiang River Scientific Research Institute | Chang J.,Shanxi Academy of Forestry science
Atmospheric Environment | Year: 2016

The aim of this paper is to evaluate the diurnal variation in soil respiration under different land use types on Taihang Mountain, North China, and to understand its response to environmental factors (e.g., soil temperature and moisture) and forest management. Diurnal variations in soil respiration from plantations (Robinia pseudoacacia, Punica granatum, and Ziziphus jujuba), naturally regenerated forests (Vitex negundo var. heterophylla), grasslands (Bothriochloa ischaemum), and farmlands (winter wheat/summer maize) were measured using an LI-8100 automated soil CO2 flux system from May 2012 to April 2013. The results indicated that land use type had a significant effect on the diurnal variation of soil respiration. The diurnal soil respiration from farmlands was highest, followed by Ziziphus jujube, R. pseudoacacia, P. granatum, the lower soil CO2 efflux was found from B. ischaemum and V. negundo var. heterophylla. The diurnal soil respiration across different land use types was significantly affected by soil temperature and moisture, and their interaction. Precipitation-stimulated soil respiration increased more in soil with low water content and less in soil with high water content. The lower diurnal soil respiration from naturally regenerated forests suggests that naturally regenerated vegetation is the optimal vegetation type for reducing global warming. © 2015 Elsevier Ltd. Source

Zhao J.,Beijing Forestry University | Zhao J.,Shanxi Academy of Forestry science | Li X.-P.,Shanxi Academy of Forestry science | Jia L.-M.,Beijing Forestry University
Beijing Linye Daxue Xuebao/Journal of Beijing Forestry University | Year: 2016

The evaluation of vegetation degradation monitoring and vegetation restoration in the coal exploration area was rarely conducted from the perspective of landscape. However, researches on the coal exploration area at landscape scale will be helpful to understand the spatial distribution pattern of vegetation. In this study, we took eastern Shanxi (Yangquan Nanzhuang coal) coal mining areas as the interference sources, and set up six equidistant lines with the distance of 800, 1 500, 2 100, 2 800, 3 500 and 4 200 m according to the quadrant sampling. Meantime, five sample lines with each length of 100 m were deployed along the direction perpendicular to the contour by using LFA (Landscape Function Analysis) method. The patch area index and landscape structure index were calculated by measuring patch quantity, patch width per unit length and average distance and size between patches per unit length. The surface soil health was evaluated around the sample lines. The evaluation index involved four vegetation indexes, i. e., surface coverage (rainfall erosion protection), perennial vegetation coverage, litterfall status and cryptogam vegetation coverage, and seven indicators of soil physical and chemical properties, i. e., degree of soil erosion, soil sediment, surface soil roughness, surface soil characteristics, soil collapse coefficient and soil texture. The purpose of the study was to reveal the distance which coal mining affected local landscape structure and function and its mechanism. The results showed that the effect of coal mining on soil total porosity and soil saturated water content weakened along the increase of distance from the coal mining area. This induced index of soil stability, soil permeability and nutrient cycling to rise accordingly. With the increase of distance from the coal mining area, each indicator related with LFA presented the trend of slow increase to rapid increase and to a stable level. Landscape function developed towards in favor of water and nutrient conservation. When the intensity of coal mining was 3.2 million tons/ year, nature reserve and city planning and construction should guarantee the minimum ecological safety distance of 4 370 m. © 2016, Editorial Department of Journal of Beijing Forestry University. All right reserved. Source

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