Spatio-Temporal Dynamics Of Forest Resources And Landscape Pattern In Tangwanghe Forestry Bureaus

By means of spatial analysis function of geographic information system software, spatio-temporal dynamics of forest resources and landscape pattern in Tangwanghe Forestry Bureaus of Heilongjiang Province was studied based on the forest type map, topography and survey data of the Bureaus in 1988 and 2008. The main conclusions were as follows:(1) The database of forest resources of Tangwanghe forestry bureaus in 1988 and 2008 has been established, and showed that forestland increased by 16485.46hm2 with increasing rate of 9.38% during twenty years. The area of open forestland, marsh, lake, selection cutting land and other class reduced. Clear-cutting land and burned area was on the verge of disappearance. Wilderness and grazing land had vanished completely.(2) Korean pine forest of Tangwanghe forestry bureaus substantially reduced in 2008 compared to 1988, and the area decreased by 19076.48hm2. The area of Korean pine forest and Larix gmelinii forest reduced 86.71% and 33.10%, respectively. While the area of Betula platyphylla forest, broadleaved forest and conifer-broadleaved forest increased by 82.78%, 39.51% and 42.31% respectively. The other main species transformed in various degrees.(3) The natural forest increased by 9270hm2 and plantation forest increased by 728.66hm2 in Tangwanghe forestry bureaus from 1988 to 2008. The area ratio of younger forest, middle age, and matured forest of Tangwanghe forest was 1:5.8:1.5 and 1:2.6:0.1 in 1988 and 2008.(4) The number of landscape patches in Tangwanghe forestry bureaus increased by 2793 in the past twenty years, and the incresing rate was 29.40%. Mean patch size reduced 22.75%. Landscape patch density increased from 0.0424 to 0.0548. Largest patch index increased from 0.4% to 0.5%. Edge density increased from 8.7657m/hm2 to 14.881m/hm2. Contagion Index decreased from 79.87 to 73.29. Shannon diversity index increased from 0.6168 to 0.8343. Shannon evenness index increased from 0.2679 to 0.3357. The amplifications all exceeded 20%. The forest landscape patches were gradually divided by boundary. Heterogeneity and diversities of landscape increased. The forest landscape tended to fragment gradually.(5) The total area, the size ratio and the edge density of forestland patches in these two stages were the largest of the twelve landscape factors of the first category (class) in Tangwanghe Forestry Bureaus. The area of forestland patches in these two stages was 175702.79 hm2 and 192188.25hm2 respectively. The ratio of patch size was 78.352% and 85.732% respectively. Edge density was 7.537 hm2 and 12.56 hm2 respectively. The mean patch size of lake was the largest, with 427.42 hm2 and 275.66 hm2 respectively. The largest patch index of marsh was the largest, with 0.352% and 0.507% respectively.(6) Broadleaved forest, coniferous forest and conifer-broadleaved forest possessed the dominant position throughout of the twelve landscape factors of the second category (species) in Tangwanghe forestry bureaus. Moreover, the superiority increased constantly. The area of most coniferous forest reduced. The area of Korean pine reduced with the greatest amplitude of 86.71%. The degree of landscape fragmentation of conifer-broadleaved forest, coniferous forest, Betula platyphylla forest, Poplar forest and spruce-fir forest increased while those of Tilia amurensis forest, Quercus mongolica forest, Pinus sylvestris var. mongolica forest and Larix gmelinii forest decreased.