Production potential and stability of a broadleaved mixed oak/hornbeam forest stand situated on a eutrophic site, Ždánický les

HURT, V.: Production potential and stability of a broadleaved mixed oak/hornbeam forest stand situated on a eutrophic site, Ždanický les. Acta univ. agric. et silvic. Mendel. Brun., 2012, LX, No. 6, pp. 135–144 The paper focuses on assessing the growth and production of a mixed oak/hornbeam forest stand established by combined regeneration in 1940 to 1942. The stand is situated at an altitude of 460 m. Since 1961, it is le to its natural development. The 25–year–old stand was characterized as an individually mixed, both diameterand height-diff erentiated pole-stage stand. The proportion of tree species was as follows: sessile oak 77 %, hornbeam 19 %, birch 1 %, lime 1 %, black poplar 1 %, wild cherry tree, wild service tree, and fi eld maple. During 41 years of measurements, the proportion of oak slightly decreased to 76 %, on the other hand, the proportion of hornbeam increased to 22%. The initial growing stock of the 25–year–old stand, 75 m3.ha−1, increased to 323 m3.ha−1 at an age of 66 years in 2008. At present, current volume increment ranged between 6.3 m3.ha−1.year−1 and 11.6 m3.ha−1. year−1 during years 1967 and 1998. Since the age of 61, the growth of the stand has decreased and then even ceased due to increased mortality of oak. sessile oak, hornbeam, birch, mixed stand, natural development, mortality, production Among autochthonous species of oak, sessile oak (Quercus petraea Matusch) and pedunculate oak (Quercus robur L.) are most common in the Czech Republic. Pubescent oak (Quercus pubescens Willd.) and turkey oak (Quercus cerris L.) can be found in considerably lower proportions in warmer areas. According to Zelena zprava [Green Report] (Mze, 2010), at present, oak occurs on nearly 7 % of timber land, however, its proportion could reach up to 19 %. Oak is our autochthonous broadleaved species being ranked among the most abundant natural components of Central-Europen vegetation. At the same time, it belongs to the economically most important Central-Europen tree species. The sense of its cultivation (even on the most fertile soils) does not consist in the total production of wood. The primary purpose of oak stands is based on the production of quality timber assortments which can be grown on fertile soils at proper tending. Oak is considered to be diffi cult to cultivate. Especially, forest tending must not be neglected and exceedingly slender trees or excessive release of stand allowed. In other case, decrease of annual increment of trees and spreading crowns occur. Quality oak stands usually do not occur in monocultures but in mixed stands. Considerable attention has been paid to problems of management of oak in the Czech Republic as well as in European countries. For example, it is possible to mention some monographs: VYSKOT et al. (1958), KLEPAC et al. (1996) and JOHNSON, SHIFLEY, ROGERS, (2009). According to GAYER (1898), BOUDRU (1889) and SEKYRKA (1901), the most suitable mixtures for growing valuable oak logs are: sessile oak – beech, sessile oak – hornbeam, pedunculate oak – ash or elm. Moreover, authors recommend mixtures of: spruce – oak, pine – broadleaves (late-fl owering