Practice-Oriented Yield Table for White Poplar Stands Growing under Sandy Soil Conditions in Hungary

Abstract

Background and purpose: White poplar (Populus alba L.) and its most important natural hybrid, the grey poplar (Populus x canescens SM.) are native tree species in Hungary, covering 3.2% of the forested area. Thanks to their favourite silvicultural and growth characteristics as well as the wood utilization possibilities, their present area is increasing continuously. The most important task ahead of Hungarian poplar growers is to improve the quality and to increase the quantity of poplar stands for wood production. To determine their growth rate and yield as exactly as possible, a yield table has been constructed which is based on the currently applied silvicultural practice. Material and methods: Chapman – Richards function with three parameters was successfully used as a growth function for constructing the height growth model. The white poplar yield table was constructed from data gathered on 50 permanent and 40 temporary plots (cca. 500-1000 m2). The age of the stands varied between 5 and 45 years. In the course of the stand surveys the key stand characteristics were measured, and then, on the basis of data collected, were calculated such major stand structure features as the average height, diameter (DBH), volume, basal area and stem number given separately for the main (remaining), secondary (removal) and total stands per hectare. Results and conclusion: The numerical (tabulated) yield table of normative nature presents data given to six yield classes (base age: 25 years) including the most imOriginal scientific paper portant stand structural and yield features expressing in terms of main stand, removing stand (which can be removed in tending operations) and the total stand. It is based on the Hungarian applied tending operations’ practice. The published yield table has already been utilized in the field of the relevant forest inventory as well.