(1) Sessile oak (Quercus petraea (Matt.) Liebl.) is one of the most important commercial species cultivated at low altitudes in the Czech Republic, and overaged coppices are a significant part of oak stands in the region. In order to secure a high-valuable timber production (e.g., through conversion of such stands into coppices-with-standards), knowledge of the potential and limits of generative regeneration is essential. This study was conducted in three oakdominated over-aged coppice stands in different stages of conversion into coppices-with-standards and characterized by different basal area (BA, from 9.3 to 14.1 m 2 ha -1 ) and relative diffuse radiation (ISF, from 12.1 to 35.5%). The study stands were compared with respect to seed predation following acorn fall and oak regeneration parameters. At the time of their fall the acorns represented a sought-after source of food for large mammals (particularly wild boar). At the end of acorn fall, 13-67% acorns were lost due to animal predation. A control evaluation conducted the following spring revealed a decrease of 92-97% in fallen acorns. Despite the major animal impact, a high reserve of acorns and saplings remained in the stands (4 600-29 000 acorns and 66 000-310 000 saplings per ha). With increasing light intensity the oak regeneration density decreased, while the height and age variability of oak regeneration increased. Although saplings were capable of surviving several years under unfavorable light conditions (even below 12% ISF), they require a minimum of 20% ISF (i.e., BA < 16 m 2 ha -1 ) to achieve sustainable height increment. Based on our results, for conversion of such stands into coppices-with-standards we recommend a maximum of 200 reserved trees (BA = 16 m 2 ha -1 ) to achieve successful height growth of the understorey.

(1-2) This study focused on the comparison of two contrasting forest regeneration types and their susceptibility to drought stress. Transpiration and biomass production were studied on young sessile oak trees Quercus petraea (Matt.) Liebl. regenerated as sprouts and seedlings, and grown in a coppice experimental site in the Czech Republic. Biomass production was estimated using destructive methods, while transpiration was derived from sap flow measurements and assessed according to the plant biometry and microclimatic conditions. Sprouts were characterized by a significantly higher diameter, height, leaf area and above-ground biomass and by a lower wood density as compared with seedlings of the same age. Moreover, the sap flow of sprouts was higher than that of seedlings, which was explained by the plant dimension. Transpiration, expressed as sap flow scaled to plant leaf area, did not differ between seedlings and sprouts when soil water was not limiting. However, during drought periods, when soil water potential dropped below -1.4 MPa, sprouts transpired significantly more than seedlings. Our results confirm that sprouts have access to a larger water pool via the old stump root system and are able to draw more water under drought. Moreover, sprouts seemed to be less susceptible to water limitations than seedlings of similar age. Less influence of drought on sprouts may partially explain their higher above-ground biomass production. Based on our results, coppice could be an appropriate management system to be adopted in sites characterized by frequent or extreme drought periods.

Based on yield tables for oak high forest and oak coppice (both first site class) and using assortment tables and assortment prices in the Czech Republic in 2009, a set of variants of conversion of high forest to coppice was simulated. Average annual cut and average gross value of annual cut of such conversions were compared with those of well-established (in terms of the age structure balance) variants of coppice and high forest. Under the existing ratio of assortment prices, established coppice does not reach the gross value yield of high forest. No variant of simulated conversions was more financially profitable than the initial high forest. Furthermore, we found out that a +16.8% increase of the current fuel wood price would counterbalance the mean annual increment of gross value of the best coppice and the worst oak high forest variant. On the other hand, a +164.7% fuel wood price increase would be necessary to counterbalance the mean annual increment of gross value of the worst coppice and the best high forest variants.

No abstract

ABSTRACT:The paper deals with the establishment of the coppice and coppice-with-standards research object under the project Biodiversity and Target Management of Endangered and Protected Species in Coppices and Coppices-withStandards Included in the System of NATURA 2000. It summarizes reasoning which preceded the selection of the site and provides a detailed description of the methodology of experimental site establishment. It specifies the rules of felling which was planned with the objective to simulate the impact of coppice and coppice-with-standards on biodiversity of endangered and protected species. It also describes the stand condition prior to and after the implemented felling, with additional emphasis on coppice-with-standards. Individual felling variants which were implemented were characterized by varying felling intensity. Close attention is paid to the evaluation of standards which is expressed by a system of score classes.