Characteristics Of Pit And Mound Microsites, Gap Makers And Species Diversity In Picea Asperata And Abies Nephrolepis Forest

Nearly 25 years, Picea asperata and Abies nephrolepis is one of the important forest communities in Heilongjiang province, have been discovered Picea asperata and Abies nephrolepis tracts phenomenon valley of death in Xiaoxing’anling. Many scholars at inland and abroad have been investigated of the gaps regeneration, but the research about the regeneration on different gap makers or pit and mound microsites was blank, this test would provide a theoretical basis and experimental data for protection and restoration of Picea asperata and Abies nephrolepis forest ecosystem.We set up a 1.5hm2 permanent standard plot in the Picea asperata and Abies nephrolepis forest. All the gap makers were studied in the plot to determined the tree the species, basal diameter, DBH, height, breakage height, formation mode, decayed level and microsites characteristics of pit and mound complex of all the gap makers. And the species, abundance, height, cover of all herbs and shrubs were measured and estimated on the plots, and their important value and richness were calculated of all pit, mound, contrast and the position of east, south, west, north and contrast in the permanent standard plot.The result showed that the number of uprooted trees was 36, which was the biggest, the number of stem breakage and base breakage was 17 and 6, respectively. There were 33 Abies nephrolepis, 19 Picea asperata.5 Betula platyphylla, and 2 Pinus koraiensis of all the gap makers in the plot. The frequency of tree species forming pit/mound complex decreased in the order of Abies nephrolepis(54.1%), Picea asperata(27%), Betula platyphylla (13.5%), and Pinus koraiensis (5.4%).29 of the 36 uprooted treefalls were located in north direction. There was significant positive correlations between pit volume and pit width, between pit volume and mound height, between pit depth and mound thickness; there were significant positive correlations between mound volume and its superficial area, between pit volume and its superficial area. On three microsites. species richness, Pielou evenness index. Simpson eco-dominance index, Shannon index decreased in the order of intact site, pit bottom, and mound top. The importance value of Rubus sachalinensis is the biggest on mound. Pit bottom was beneficial to the growth of Urtica laetevirens and Impatiens nolitangere. Species richness on mound top and on pit bottom was the biggest when decayed level of uprooted treefalls was level 2(0.94) and level 5(1.72), respectively. Plants’ average total coverage and their average density were in the sequence of intact site>mound top>pit bottom.The value of Pielou evenness index(J). Simpson eco-dominance index(D). Shannon index(H) were listed in the order of all uprooted tree>stem breakage>base breakage. Within the plots of uprooted tree and breakage, the important value of Aegopodium alpestre was the biggest, 14.2 and 13.2. respectively. The dominant species in the plots of uprooted trees are Impatiens nolitangere and Urtica fissa, but Aconitum carmichaeli in the plots of breakage. Under the same decayed level of treefalls, species richness in the plots of uprooted trees was more than in the plots of breakage. Except the stem breakage west plot shrubs’ richness was the biggest,the herbs’ and shrubs richness in the east, south, west, north plots were all uprooted tree>stem breakage>base breakage. The herbs’ richness in the east, south, west, north plots of base breakage and stem breakage were smaller than the control, but opposite in uprooted tree plots.