Ecology and Management of Black Walnut (Juglans nigra L.) in Hungary

Background and Purpose: Black walnut (Juglans nigra L.) was one of the first forest tree species introduced and acclimated from North America to Europe in the 17th century. Although native to North America, black walnut is now naturalized and widely planted throughout Europe. In Hungary, this species has played an important role in forest management. Black walnut can grow on various sites, but careful site selection and well-planned management practices are needed to produce successful plantations. Due to the increasing interest in black walnut growing in many countries this study complied with the aim of giving a summary on the base of research and improvement connected with the species over the past decades. Materials and Methods: Black walnut produces a well-closing, favourably differentiated stand structure in consequence of the great genetic diversity of single trees. It utilizes well the leaks of the tending cuttings. In this manner, because of its quick height growth, the systematic, individual selective method can be favourably combined with more frequent stem number reduction. The objective of tending should be to produce a high proportion of good quality saw logs from stands of yield class I, II, III and IV, and some other smaller-dimension industrial wood from stands of yield class V and VI. Conclusions: In Hungary, black walnut is one of the most valuable exotic tree species, mainly because of its wood excessively used in furniture industry. Black walnut is used in furniture industry both as solid wood and veneer. This species is among the most expensive furniture woods in the world due to its appealing surface figure and colour. Its wood is also used for making musical instruments, turned and carved ornaments, statues and marquetry. Black walnut stands are to be important in carbon sequestration, soil stabilization, and water quality protection as well

Promising Leuce poplar clones in sandy ridges between the rivers Danube and Tisza in Hungary: a case study

An intensive integrated research and development work has been carried out on the improvement of Leuce poplars including primarily the native white poplar (Populus alba L.) and its natural hybrid grey poplar (Populus × canescens). More than 70 percent of the Leuce poplar stands can be found on calcareous sandy sites in the Danube–Tisza region, so they play a significant role in the poplar management of this part of the country. The most important task ahead of Hungarian poplar growers is to improve the quality of poplar stands and plantations based on selecting new clones and cultivars. The growth and yield of four promising Leuce poplar clones was evaluated on a marginal site in central Hungary. The clones ‘H 425-4’ (Populus alba L. × Populus alba L.), and ‘H 758’ (Populus alba L. Mosonmagyaróvár 124) seem to be suitable for wood production, while the ‘H 427-3’ (Populus alba L. × Populus alba L. cv. Bolleana) and ‘H 422-9’ (Populus alba L. × Populus grandidentata (Michx)) clones (with decorative stem form) could be better used for tree lines and ornamental plantations

Hegylábi parlagokon kialakuló élőhelyek típusát és növényzetének fajösszetételét befolyásoló tényezők

Magyarországon az 1950-es évektől folyamatosan keletkeznek parlagok, melyek egy jelentős részén a növényzet spontán szukcessziója zajlik. A hegylábi lejtőkön, az erdő és az erdőssztyepp átmeneti zónájában a kialakuló növényzet típusa nehezen megjósolható, mert ezt számos lokális tényező is befolyásolja. Kutatásunkban a térbeli helyzetnek (kitettség, lejtés, erdőtől való távolság), a felhagyás korának és a cserjésedésnek a hatását vizsgáltuk a parlagokon kialakuló növényzet összetételére. Mintegy 170 ha-nyi, fokozatosan felhagyott parlagterületet vizsgáltunk a Pilis-hegységben. A parlagokat a felhagyás ideje alapján 3 korcsoportba, a cserjésedettség mértéke alapján pedig 3 folttípusba soroltuk. Minden típusban 12-12 db, 2x2m-es növényzeti felvételt készítettünk, összesen 108 db-ot. A háttérváltozók hatását a fajgazdagságra és néhány fajcsoportra (gyep specialisták, erdei specialisták) általánosított lineális modellek segítségével vizsgáltuk. A cserjék mennyiségének és az erdőtől való távolságnak esetünkben nagyobb hatása volt a fajgazdagságra és a fajösszetételre, mint a felhagyás óta eltelt időnek. Cserjék megtelepedése nélkül fajgazdag száraz gyepek alakultak ki a parlagokon, a cserjésedés viszont az erdei fajok számát növelte, ezáltal valószínűleg az erdő kialakulását segíti

Weak evidence of long-term extinction debt in Pannonian dry sand grasslands

Habitat loss is one of the major drivers of the reduction in biological diversity worldwide. European dry grasslands are particularly endangered. However, the persistence of populations can temporarily mitigate species loss - a process referred to as 'extinction debt'. We test this hypothesis using historical and present day habitat maps and current plant biodiversity data collected in the forest-steppe zone of Europe. In 16 5 km × 5 km study sites, representing the landscape heterogeneity of the Kiskunság region (Hungary), 86 20 m × 20 m vegetation plots were surveyed in open and closed calcareous sand grasslands. Grassland diversity was measured as the number of specialist species, defined by statistical fidelity measures using primary and secondary grassland plots. Landscape context was quantified using the areal extent of semi-natural forest-steppe vegetation in a 300 m neighborhood of the plots, based on recent and historical maps (1783, 1860, 1950s, 1987-1989 and 2005). The number of specialist species was estimated with Poisson generalized linear models using the present landscape context, climatic conditions, and a proxy of soil type as covariates. To test for the effect of historical legacies, Pearson residuals from the present models were tested for significant relationships between the residuals and the historical landscape contexts using linear models. We found that the present landscape context had no significant relationship with the specialist species richness of the primary grassland fragments. However, we found a significant relationship between the historical landscape context of the 19th century and the residuals of the present model. Even though the extent of natural vegetation in the 20th century showed more drastic changes, the landscape context in 1950s and 1987-1989 exhibited no significant statistical relationship with the residuals. This delay of species loss is consistent with the extinction debt hypothesis. © 2013 Elsevier B.V. All rights reserved