The Soil Seed Bank Characteristics And The Relationship With The Vegetation In Different Forest Types In Changbai Mountain Area

Coniferous and broadleaved mixed forest which have high productivity, a large amount of material and containing a large number of valuable timber species is the top ecosystem in Northeast China's mountainous areas.It's famous for its unique construction and rich species diversity in the northern temperate forest of the world. In recent years, due to large areas of logging, its original type has been replaced by different types of secondary type. This study selected two kinds of coniferous and broadleaved mixed forest, two kinds of secondary birch forest and two kinds of plantations in Changbai Mountains as an object of study. By large numbers of field investigation, sampling observation and laboratory analysis, we discuss diversity characteristics of species composition, the composition characteristics of the soil seed bank and similarities between the soil seed bank and standing vegetation or seedlings in different types of forest. Main results are as follows:1. In five forest types, the order of the size of species diversity index are as follows: Coniferous and broadleaved mixed forest>Secondary birch forest>Primeval forest>Pinus sylvestris forest>Korean pine forest; in the same forest types, in addition to virgin forest, the size of the species diversity both as follows: Shrub layer>Herb layer>Tree layer.2. Because different vegetation composition between five different forest types, resulting in the types and reserves of forest soil seed bank are different, the virgin forest: 1306.9grain/m~2; Coniferous and broadleaved mixed forest:1195.7grain/m~2; Secondary birch forest: 2080.5grain/m~2; Pinus sylvestris forest: 91.5grain/m~2; Korean pine forest 131.9grain/m~2.3. In primeval forest and coniferous and broadleaved mixed forest, the horizontal distribution of soil seed bank to express as uniform distribution; In secondary birch forest,pinus sylvestris forest and korean pine forest, the horizontal distribution of soil seed bank to express as clumped distribution. The vertical distribution of soil seed bank is extremely obvious that the number of seeds in litter layer accounted for 70.6% of the total, in 0-5cm soil layer accounted for 20.1% and in 6-10cm soil layer accounted for 9.3%.4. Soil seed bank and the ground vegetation is relatively high similarity in the coniferous and broadleaved mixed forest, primeval forest and secondary birch forest(C_j = 0.52, 0.4, 0.4). But soil seed bank have a low similarity with the ground vegetation in pinus sylvestris forest and korean pine forest (C_j = 0.11, 0.25). Seedling abundance and diversity of the original forest were highest in different forest types, soil seed bank and seedling similarity is also high (C_j = 0.53), but have lower similarity in coniferous and broadleaved mixed forest and secondary birch forest(C_j = 0.35, 0.33).5. A small number of seedlings under the forest, primeval forest: 0.08 plants/m~2, coniferous and broadleaved mixed forest: 0.28 plants/m~2,secondary birch forest: 0.11 plants/m~2. Under natural conditions, The rate of transform the seed in Soil seed bank into seedlings is very low which less than 0.03%.