Growth Regularity And Cultivation Technology Of Catalpa Bungei Plantation

Catalpa bungei is a precious tree species in northern China,with good wood quality and wide distribution.At the present,due to the lack of related research on the growth regularity of C.bungei plantation,the management process is not sufficient scientific.At the same time,there is much research about cultivation technology of C.bungei plantation,but that usually focuses on one aspect of cultivation technology so that a cultivation technology system has not been completed.Therefore,it has great theoretical and practical significance to research growth regularity and core cultivation technology(site selection,fertilization,pruning,etc.)of C.bungei plantation.In this study,the research object is the C.bungei Plantation of Luoning County,Henan Province.81 standard plots are set up to collect data related to site factors,stand factors and cultivation measures.Based on statistical analysis of field test and indoor experiment,the most suitable cultivation mode and site condition for the growth of C.bungei are selected.At the same time,this study selects 7 representative individuals for stem analysis,analyzes the growth regularity of C.bungei and establishes prediction models.Also,through the fertilization and pruning trials of Shishou City,Hubei Province and Jinan City,Shandong Province,the influence of the amount and method of fertilization and the season and strength of pruning to the growth of C.bungei is analyzed.The most suitable fertilization and pruning technology for the growth of C.bungei are summarized.At present,after two years of tests,the following results have been obtained:(1)The growth regularity of height,diameter at breast height(DBH)and volume of C.bungei are different.The rapid growth period of height,DBH and volume is respectively before the 15 th year,between the 3rd year and the 15 th year and after the 15 th year,and the rest are slow growth periods.Also,the C.bungei has not reached quantitative maturity at the37 th year,so the age is greater than 37.(2)Among growth equations of trees,the Sloboda equation is more accurate to predict the growth process of height,DBH and volume of C.bungei.The average relative error of height,DBH and volume is respectively 2.27%,3.23% and 12.13%.(3)The cultivation of C.bungei should be agroforestry mode.Also,the cultivation density should be selected according to the purpose of cultivation.If the cultivation purpose is single high-quality timber of C.bungei,there should be no more than 500 individuals per hectare.If the cultivation purpose is total wood yield of C.bungei,there should be more than 500 individuals per hectare.(4)Site conditions should be considered in C.bungei plantation with traditional forestry mode.Firstly,there is no clear demand about the choice of slope direction.Secondly,a slower slope area that is between 6° and 15° should be selected.Finally,a downhill area should be selected.In addition,among soil physical and chemical property,the height and DBH of C.bungei is more closely correlation with p H,organic matter,total nitrogen and phosphorus and available nitrogen and phosphorus,so the suitable soil for C.bungei should have p H that is close to neutral,good breathability and water holding capacity and high organic matter and nutrient content.(5)The results show that integrated fertilization with water and fertilizer is more suitable for young plantation than conventional fertilization,even though both can increase the growth of C.bungei.Therefore,it is recommended to promote the integrated fertilization with water and fertilizer in the fertilization process of young plantation.The results also show that the fertilization amount is important to growth of C.bungei,so formulated fertilization technique is more suitable.To be specific,each tree is applied with 60 g of nitrogen,20 g of phosphorus pentoxide and 40 g of potassium oxide.(6)The young plantation should be pruned in spring and the branches below 1/2 of height should be cut at one time because this method can improve the shape of C.bungei and has the least impact on the height and DBH of C.bungei.The middle-aged plantation should not be pruned in order to avoid reducing the yield of C.bungei plantation.