The Effect of Thinning on the Diameter Increment in Black Locust (Robinia pseudoacacia L.) Stands

• Main Authors: MEILBY, Henrik, RÉDEI, Károly
• Format: Article
• Language: English
• Published: Sciendo 2009-01-01
• Series: Acta Silvatica & Lignaria Hungarica
• Subjects: Robinia pseudoacacia L.; thinning trial; diameter increment
• Online Access: http://aslh.nyme.hu/fileadmin/dokumentumok/fmk/acta_silvatica/cikkek/Vol05-2009/05_redei_mailby_p.pdf
• ISSN: 1786-691X; 1787-064X

Black locust is one of the most important stand forming tree species in Hungary, coveringapproximately 23% of the forested land (410 thousand ha) and providing 23% of the annual timber cutof the country. Hence, during the past two decades several experiments with this species have beencarried out in the country. This paper investigates the influence of thinning on the diameter incrementin an experiment including four plots. One plot was left as an unthinned control plot and three plotswere thinned with various thinning intensities at age 22. The experiment was measured at ages 22, 27,32, and 36. Apparently the thinning intensities applied on two of the plots did not come up to theintensity required to influence the diameter growth of the remaining upper-storey trees. Therefore, fora given tree size the growth of the trees on these two plots did not differ significantly from the growthof similar trees in the unthinned plot. By contrast, significant thinning effects on the diameterincrement of individual trees were observed on the most heavily thinned plot. Here the diameterincrement was enhanced for trees with diameters of less than 20 cm, whereas the largest trees of thestand exhibited moderately increased growth. Apparently a stand density corresponding to the heavythinning treatment (Fw values of 22-23) is required to get a significant thinning response. On the otherhand, to avoid thinning shocks, it may be recommendable to apply two moderate thinning treatmentsinstead of a single heavy one.