| In this paper, state owned Pengzhou forest farm which located in the western margin of Sichuan Basin is selected as the study area. Based on the stand maps(1:10,000) and subcompartment cards of the 1988 second type inventory of forest resources conducted in study area,conducted by the theory and method of landscape ecology,used GIS,VDDT (Vegetation Disturbance Dynamics Tool) and TELSA (Tool for Exploratory Landscape Scenario Analyses), taked rodent damage and earthquake as natural disturbances, harvesting as human disturbance, closing the land for reforestation, artificial stimulating naturalregeneration and reforestation as management measures,6 scenarios had been set up based upon different disturbances and forest management measures to simulate and forecast the landscape dynamics of study area.The main conclusions are demonstrates as follows:(1) At the beginning of the simulation(1988), the rank of the first-grade landscape type’s area was shrub land(13735.68 hm2)>forest land(9367.1 hm2)>open forest land(4049.08 hm2)> unused land(3271.32 hm2)> suitable land for forest(1590.97 hm2)> young afforested land(323.81 hm2).Shrub land distributed most widely with the largest area, which was the main landscape type of study area. Forest land was dominated by natural plantations,which were dominated by Abies fabri plantations. Artificial plantations were mainly distributed in the southeast of study area, Cryptomeria fortunei plantations’area was biggest, Cunninghamia lanceolata plantations’was less, and Metasquoia glyptostroboides plantations’was least.The differentiation of young afforested land’s, suitable land for forest’s and open forest land’s patches was relatively high, others’ were low.After 80 years’ natural succession, forest land area increased 2996.25 hm2, young afforested land area decreased to 0, open forest land decreased 2672.44 hm2. In the early stage of succession, forest land was mainly formed by near-mature stand and mature stand, when it come to late stage of succession.the over-mature stand were most.(2) Under the forest management measures such as closing the land for reforestation, artificial stimulating natural regeneration and reforestation,the rank of the first-grade landscape type’s area was turn to forest land(14468.82 hm2)> shrub land(13735.68 hm2)> unused land(3271.32 hm2)> open forest land(699.26 hm2)> suitable land for forest(82.02 hm2)> young afforested land(47.09 hm2).The patch density of forest land decreased nearly half, those of open forest land and suitable land for forest increased over 1 time and nearly 10 times.(3) The influence of rodent damage on artificial plantations were:the area percentage of young growth and half-mature forest of Cunninghamia lanceolata and Cryptomeria fortunei increased,and those of the rest decreased,the age structure of Cunninghamia lanceolata plantations and Cryptomeria fortuneii plantations was becoming smaller.During 80 years simulation,466.95 hm2 trees were killed by common rodent damage,805.03 hm2 trees were killed by severe rodent damage.(4) The influence of harvesting on artificial plantations were:the age structure of srtificial plantations was becoming smaller,and young growth and half-mature forest were most,over-matuer forest was missed. During 80 years simulation,the total volumes of harvested Cunninghamia lanceolata,Cryptomeria fortunei and Metasquoia glyptostroboides were 237557.36m3,755203.81 m3 and 301950 m3, at the same time, the annual area of artificial plantations decreased 402.78 hm2 (20.79%).(5) The interaction between rodent damage and harvesting is:under the influence of rodent damage,the the total volumes of harvested Cunninghamia lanceolata, Cryptomeria fortunei decreased 43.38% and32.09% during 80 years; under the influence of harvesting, the total area of trees killed by common rodent damage and severe rodent damage both increased nearly one time.(6) Earthquake caused the areas of forest land, open forest land and shrub land decreased 15.78%,13.28% and 17.99%.Meanwhile, earthquake increased the spatch densities of forest land, open forest land, shrub land, suitable land for forest and unused land.(7) Under the comprehensive effects of existing management measures and the main disturbances,after 80 years’ dynamics, the area of forest land, young afforested land and unused land increased 32.27%、100.68% and 22.99%; the area of open forest land, shrub land,and suitable land for forest decreased 53.59%、2.92% and 95.44%.Finally,the rank of the first-grade landscape type’s area was shrub land> forest land> unused land> open forest land> young afforested land> suitable land for forest. The spatch densities of the first-grade landscape types all increased, the effected degree by disturbances ranked as uitable land for forest> unused land> open forest land> young afforested land> shrub land> forest land.The areas of Abies fabri plantations, Betula albo-sinensis plantations, Acer franchetii plantations,Cryptomeria fortunei plantations, Cunninghamia lanceolata plantations, Metasquoia glyptostroboides plantations increased 24.35%,20.62%,8.28%, 154.48%,111.91% and 356.74%,and the effected degree by disturbances ranked as Cunninghamia lanceolata plantations> Abies fabri plantations> Cryptomeria fortunei plantations> Acer franchetii plantations> Metasquoia glyptostroboides plantations> Betula albo-sinensis plantations.The area and area percentage of young growth increased,and those of the rest age groups all decreased. |
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