Study On Decomposition Process Of Main Tree Species Stumps In Broad-leaved Korean Pine Forest In Changbai Mountain

There are lots of stumps left in the broad-leaved Korean pine forest in Changbai Mountain to chang the forest environment. The peripheral nutrient around the stumps changed during the stump decomposition to be the part of the nutrient pool in the broad-leaved Korean pine forest. The correlation study about the stump decomposition is rare at home and abroad. Many study focus on the the stump above or under the soil seperatly. Few combined the stump nutrient loss with the fungi activity together. We need to combine the stump above and under the soil together to fill the research gaps in the forest ecology system. And it is the first time to study both fungi activity and nutrient together to describe the stump decomposition in the broad-leaved Korean pine forest in Changbai Mountain. The research is the supplement for the forest ecology nutrient circulation.We select the main tree species in Changbai Mountain, include Pinus koraiensis,Fraxinus mandshurica,Betula platyphylla and Pobulus davidiana, to research the stump's decomposition.We focused on the nutrient lossing in the stump and soil around the stump, the corse fiber loss and the density changes during the stump decomposition to describe the stump decomposition. The wood rotting fungi are the driving of the stump decomposition. The investigation shows that different tree species stump has different decomposition process. The environmental factors and the material composed in the stump both affect stump decomposition. Hard wood tree species Pinus koraiensis and Fraxinus mandshurica need more time than soft wood tree species Betula platyphylla and Pobulus davidiana to finish the decomposition. The sequence is: Pinus koraiensis>Fraxinus mandshurica>Betula platyphylla>Pobulus davidiana.The main fungi species on the stump are belong to Agarcales and Aphyllophorales, some are Ascomycetes. All fungi parasite on the stump with the selectivity for they have different enzyme activity. The polypore is the main fungi on broad-leaved stumps, but on the conifer, it is Tricholomataceae and Pleurotaceae. The fungi species was reduce after interspecies competition on the Pinus koraiensis stump in 12 years. But the fungi amount increase with the further decomposition. For Betula platyphylla, the fungi species and amount, in the initial period of the stump decomposition, are both more than the end of the 12 years which was the period we invested. So Betula platyphylla decomposed completely in 12 years. For Fraxinus mandshurica, the fungi amount changed little during 12 years, but the species arise in the 10th year of the sutmp decomposition. The Pobulus davidiana decomposed mostly in 5th year, after that the fungi amount decreased. After the 12 years decomposition, the fungi species and amount was lest on the Pobulus davidiana stump.The research shows that there was positive correlation between the fungi amount and the stump diameter, negative correlation between the fungi amount and the light intensity. The correlation isn't same for different tree species.From the data we know that the stump nutrient and the corse fiber loss were consist with the fungi activity on the stumps. It is the stump section that fungi's activity was intense and at the same time, that was the place where decomposition was most intensive. The decomposition activity began from the stump section and the root. And the corse root decomposition is less than the section of the stump. The heart of the stump near the soil surface decomposed slowly.