Growth and Yield of Black Locust (Robinia pseudoacacia L.) Stands in Nyírség Growing Region (North-East Hungary)

Background and Purpose: In Hungary the black locust (Robinia pseudoacacia L.) can be considered as the most important fast-growing stand-forming exotic tree species. Due to its favourite growing technological characteristics as well as its wood utilization possibilities the present area occupied by black locust stands amounts to 460 thousand hectares. Of its growing districts Nyírség (North-East Hungary) has a distinguished importance where the area of black locust stands is appr. 22 700 hectares. The Nyírség region can also be considered as one of the best black locust growing regions in the Carpathian basin. To determine their growth rate and yield as exact as possible a local numerical yield table has been constructed on the basis of surveys of the experimental plots established in pure, managed black locust stands. Material and Methods: The local black locust yield table was constructed from data gathered on 105 sampling plots with average area of 1 000 m2. The total area of the experimental plots was 9.295 ha. In the course of the stand surveys the key stand characteristics were measured, and then, on the basis of data collected, were calculated 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: Black locust yield table presented in this paper is the first local one in the history of the Hungarian black locust research. The programmable editing procedure allows extension and formal change of information content of the yield table according to different demands. This type of yield tables (standards) somewhat reflects the local growing-technological (forest tending) characteristics better way, on the other hand refer to the trend of quality and quantity changing of black locust stands growing in a given area