The influence of the density of the natural regeneration of the seedlings of Hungarian (Quercus frainetto) and Turkey oak (Quercus cerris) on the individual changes of trees following the woodland stage.
2014; Volume: 44; Issue: 1 Linguagem: Inglês
ISSN
1841-8317
Autores Tópico(s)Seedling growth and survival studies
ResumoThe woodland stage in the mixed stands of Hungarian and Turkey oak triggers ecosystem processes on account of the passage from the individual growth stage to gregarious growth. Interspecific and intraspecific competition due to density and competition for resources leads to a level of self-regulating of the ecosystem that makes each tree to behave according to the global strategy of the stand to ensure maximum stability. In the context of the current climatic changes, the Turkey oak has been affected more than the Hungarian oak, which has taken advantage of the well-known frequency rate (2-5 years), managing to install through higher natural regeneration rates. The proportioning of the mixed stands can be achieved through forestry works. For these reasons, research on the behaviour of the Hungarian oak and the changes at different growth stages is needed. Knowledge about the changes of each individual tree leads to the management of works in space and time in order to protect them in the competition with the Turkey oak. INTRODUCTION The need to maintain the Hungarian oak in theGetic Plateau has become a serious concern in forestry. The ecological value of the Hungarian oak is given by its ability to optimallyexploit the areas with heavy compact soils and with a very high content of clay, to which we add the economic value of the Hungarian oak. The physiological decline of the Hungarian oak was highlighted by the decrease of the natural regeneration capacity caused by high frequency rates and/or lack fructification (Bercea, 2008, 2013). In this context, the current climatic changes, in-depth research on the evolution of the Hungarian oaksamplesfollowing the woodland stage is required, not only in terms of the changes caused by the gregarious state, but also regarding its relations with the Turkey oak samples, with a view to protecting the Hungarian oak through forestry works. Our research aims to highlight the changes undergone by the Hungarian oak in the state of thickness of naturally regenerated mixed seedlings, as well as the scientific grounding of the methods to facilitate them. MATERIALS AND RESEARCH METHODS The research was conducted in sample areas plantedin 1998, located in phytoclimatic average conditions for the Hungarian and Turkey oak trees in the widespread forests in the western part of the Getic Plateau,at Simian, Strehaia, Filiasi, Melinesti, Dragasani (Bercea , 2007). In the forest of Macrea, thesample unit 82 M (ua) of the RD furthermore, research focused on the evolution of the Hungarian and Turkey oak trees during the growth and development stages. Measurements and observations were carried out in the former open group cuts during the regeneration process by applying progressive cutting to two 2-metre wide samples, one tothe south and the otherto the east-west. The results of the measurements and observations were recorded in tables for each species and for the whole stand. Tables were processed using Excel, and plotted using the same software. The density of the seedlings, expressed as the number of seedlings/m , is influenced by the area in which they were planted. The lowest density of seedlings was recorded in the centre (C), followed by a steady increase in the number of seedlings in the middle (m) and peripheralarea (P). Starting from the peripheralarea to the outer area (o) under the woodland, the density of the seedling increases sharply due to the larger number of fully grown trees able to bear fruit and due tothe microclimatic conditions allowing for the planting and growing of seedlings in this area (Fig. 1) Fig. 1 Density of seedlings according to the position in the group cut (Bercea, 2007) The high density of seedlings springing out in 2004, in the outer area of the group cuts, was steady all over the years over which measurements were made. The result of variance analysis on the density of the Hungarian and Turkey oak seedling, depending on the area of the group cut, is indicated as significant (p), highly significant (***), and is explained by the negative effect of heat and light the central (C) and middle (m) areas during summertime (Bercea, 2007). The continued research in 2012 and 2013 emphasized the natural elimination process characteristic of young trees (Bercea, 2013). Research was further carried out in the same woodland in 2013 si 2014 in order to identify and determine the natural trees pruning in the former regeneration group cuts, in compliance with the trial markets to the north-south and east-west. The height of the specimens and the prunned stem were measured for the two species. Desimea puietilor in functie de pozitia in interiorul si la marginea ochiurilor
Referência(s)