tailieunhanh - Báo cáo lâm nghiệp: "Stability of the development of basic stand parameters of beech yield tables constructed on the basis of short-term observations on research plots"

Tuyển tập những bài báo cáo nghiên cứu khoa học hay nhất được đăng trên tạp chí JOURNAL OF FOREST SCIENCE đề tài: Stability of the development of basic stand parameters of beech yield tables constructed on the basis of short-term observations on research plots. | JOURNAL OF FOREST SCIENCE 56 2010 7 323-332 Stability of the development of basic stand parameters of beech yield tables constructed on the basis of short-term observations on research plots R. Petrás J. Mecko National Forest Centre - Forest Research Institute in Zvolen Zvolen Slovakia ABSTRACT We compared the development of yield curves of mean and top height and development of mean diameter according to yield tables of beech which were constructed on the basis of short-term investigations with empirical data of repeated measurements on permanent research plots. We performed our study on 86 permanent research plots with 550 repeated measurements. The length of the interval of repeated measurements on the research plots is in the range of 10-43 years. We quantified differences in the development of model and empirical curves by help of basic statistical characteristics. The results show that the actual growth of mean heights is more intensive than in models of yield tables. An opposite situation is for mean diameters. The development of top heights corresponds to the actual growth of beech stands. Keywords beech mean diameter mean height top height yield curves yield tables At present yield tables are used very broadly in forest practices and as stated by Eckmullner 1992 with regard to all restrictions positive as well as negative aspects of their use it is necessary to consider their use also in future. As the last author Pretzsch 2001 summarized the issues of their history and construction for about the last four generations. On an example of mostly German authors he analysed in detail the most important methodical issues separately for each generation. Based on his classification we can consider the 3rd generation of yield tables constructed on the basis of regression fitting of stand data from research plots by mathematical functions the most distributed. A basis of their high value and reliability is in addition to appropriate methodology especially reliable .