Impacts Of Hathpace Soil Preparation And Caudex Cutting On Growth Of Manchurian Ash Seedlings Planting Under Its Natural Forest

It is prevalently poor of Machurian ash's (Fraxinus mandshurica Rupr.) natural regeneration under its mother woodland in Northeast of China. One-year-old ash seedlings were planted under ash natural secondary forest about 50 years old in Laoshan Plantation Station of North East Foresty University (Shangzhi, Heilongjiang province) . By treatments of hathpace soil preparation and caudex cutting with blocks experimental design, the growth of these ash seedlings was thoroughly investigated and analyzed during the first 3 years after planted. The main results were as follows. Heigh content of Soil mean surface moisture (41.26%±7.58%) didn't result in the key facts on the growth of planted ash seedlings under its natural secondary forest. Hathpace soil preparation significantly increased ash seedlings survival during the first 3 years. The role of caudex cutting on ash seedlings survival correlated with that of hathpace soil preparation. The influence of hathpace soil preparation and caudex. cutting on ash seedlings mortality and on their survival was on the contrary during the same period. Through treatments of hathpace soil preparation and caudex cutting, not only the height and basal diameter increments, but also the respective accumulation and distribution of root, stem, foliage and the gross biomass of ash seedlings varied prominently. Furthermore, the results of hathpace soil preparation during the whole growth season in 2004 indicated as follows. The soil mean surface moisture content was significantly decreased. Hathpace soil preparation sharply weakened the correlationship between seasonal change of soil mean surface moisture and seasonal distribution of precipitation. However, the coherence of the soil moisture condition was distinctly enhanced. The soil surface temperature was not improved prominently, but the homogeneity of its daily and seasonal variety was effectively maintained. Both the soil mean and extreme surface temperatures displayed similar seasonal change currents whether hathpace soil preparation or not. In conclusion, the conditions of soil surface moisture and temperature were changed by the treatment of hathpace soil preparation, which highly availed the growth of ash seedlings in this research.