NITROGEN NUTRIENT MECHANISM IN SECONDARY SUCCESSION PROCESS OF THE MIXED BROAD-LEAVED/ KOREAN PINE (PINUS KORAIENSIS) FOREST

INTRODUCTlONThemixcdbroad-leaved/Pinuskor`IiensiSforestwhichisoneofthemainforestsofNortheastChina,isintlleCllangbaiMountail1s(JilinProvince)a11dtheXiaoxing'anMotu1-tains(inHeilonroIangProvince).Thisistl1empicalmixcddeciduous/co11iferforestvegcta-tionofthcarca.But,duetocuttingandanunbalancebctWeenharvesti11gandanntlalin-crement,themixedbroad-leaved/PinuSko-raiensIjforestsha1,ebeenreplacedwithsec-ondaryforests(includingthelargearPaofsecondaryforestleftfrol11thepast)sinceltsclearcutti…

NITROGEN NUTRIENT MECHANISM IN SECONDARY SUCCESSION PROCESS OF THE MIXED BROAD-LEAVED/ KOREAN PINE (PINUS KORAIENSIS) FOREST

Chemical and biochemical analysis methods were used to monitor the vedations of nitrogen nutrient among the dominance trees species in secondary succession process of the mixed broad - leaved/Korean pine forest on Changbai Mountains, Northeast China. Amounts of total nitrogen, anunonium and NRA in soils of virgin broad-leaved/Korean pine forest which is in climax were higher than those of secondary birch forests those are in succession Stage. The amount of nitrate was in the other hand. In climax, dominance trees species are tolerant mesophytic trees such as Pinus Koraiensis, Tilia amurensis, Acer mono and also Fraxinus mandshurica, they are all ammonium nitrate adapted species, but they show a preference for the anunonium rather than those of the pioneer trees species in secondary birch forest, such as Populus davidiava and Betula platyphylla. Because they have more ammonium in their leaves and roots, especially Pinus koraiensis. Populus davidvana and Betula plaaphlla are intolerant trees, amounts of nitrate and total nitrogen is higher in their leaves and roots and also NRA in their leaves, so they preference for the nitrate rather than the others.In secondary birch forest, the regeneration trees species adapt their nitroggn nutrient to the variation of nitrogen nutrient situation in soil, finally they could survival well and the secondary birch forest would succession to climax. In climax, dominance trees species adapt their Nitrogen nutrient to the situation in soil and there are not strong competition in nitrogen nutrient among them, so they can coexist well and keep the climax as stable vegetation.