Strict Forest Reserve Research in the Margin of the Carpathians, the Vár-hegy Case-Study

Sixteen forest reserves are situated in the northern part of Hungary which belongs to the Carpathian region according to EURAC delimitation (Ruffini et al. 2006). These Hungarian forest reserves expand the natural forest remnant/forest reserve net of the Carpathians towards the lower hilly region, representing the deciduous beech and oak forest belts near their lower (xeric) distribution limits. This paper outlines the Hungarian forest reserves belonging to the Carpathian region and the preliminary results of current projects in the Vár-hegy Forest Reserve (Bükk Mts., Hungary) as a case study. The alteration of tree species composition was investigated here based on the reconstruction of forest history in the previous 130 years (management period) and analyses of forest stand inventory. In another project CO2 sequestration changes of these forest stands were modeled since the clear-cutting in the 1880th and carbon stored in the forest ecosystem compartments was estimated. Our results show that the forest reserve stands are presently in a transition state from the managed forest towards a more natural mixed forest with several age-classes

The effects of stand characteristics on the understory vegetation in Quercus petraea and Q. cerris dominated forests

The shelterwood system used in Hungary has many effects on the composition and structure of the herb layer. The aim of our study was to identify the main variables that affect the occurence of herbs and seedlings in Turkey oak-sessile oak (Quercus cerris and Q. petraea) stands. The study was carried out in the Bükk mountains, Hungary. 122 sampling plots were established in 50-150 year old oak forests, where we studied the species composition and structure of the understorey and overstorey. The occurence of herbs was affected by canopy closure, the heterogenity and patchiness of the stand, the slope and the east-west component of the aspect. The composition of saplings was significantly explained by the ratio of the two major oak species in the stand and the proximity of the adult plants. An important result for forest management was that sessile oaks were able to regenerate almost only where they were dominant in the overstorey

The role of seed bank in the dynamics of understorey in an oak forest in Hungary

We studied the potential role of seed bank in the dynamics of the understorey in a turkey oak-sessile oak forest (Querceteum petraeae-cerris) in Hungary. We used long-term records of the herb layer (1973–2006) and the seed bank composition of 2006 to assess the role of seed bank in the regeneration of herb layer. The total cover of herb layer decreased from 22% (1973) to 6% (1988), and remained low (<10%) till 2006; coinciding with the increasing cover of secondary canopy dominated by Acer campestre. We found a low density seed bank (ca. 1300 seeds/m2). Altogether 33 species were germinated from the soil samples. A few generalist weed species composed the majority of seed bank. It was possible to assign a seed bank type for 19 species; 14 species out of 19 was long-term persistent. We found that the characteristic perennial forest herbs and grasses had only sparse seed bank. The Jaccard similarity between vegetation and seed bank was low (<30%). Our results suggest that the continuous establishment of forest herbs are not based on local persistent seed bank; it should be based on vegetative spreading and/or seed rain

Biotic and abiotic risks of soil biochar treatment for food safety and human health

Pyrolysis technology facilitates the heating of organic waste biomass in a very low oxygen environment to temperatures over 400 °C. The high carbon content and surface area of the char produced via slow pyrolysis makes it suitable for a range of purposes that would sequester the carbon it contains. For example, there is a growing interest in its use as a soil amendment, which enhances plant growth and nutrient use efficiency

The effect of climate change on soil organic matter decomposition

In the last few decades the climate of Síkfkút ILTER Forest (Hungary) became warmerand dryer. Due to the climate change the species composition of forest has been changing, and thetotal leaf litter production has been slightly decreasing. According to our long-term litter manipulationfield experiment, which is part of ILTER Detritus Input and Removal Treatments (DIRT) Project, aftera 4-5 year treating period, at the No Litter, No Root and No Input treatments the soil organic C and Ncontent, the soil bacterial and fungal count, the soil pH, the soil enzyme activity, and soil respirationdecreased. Increased soil temperature raises soil respiration exponentially, and thus if the average soiltemperature increased by 2 oC at the dry Síkfkút site, soil respiration would increase by 22.1%. Thisincrease would be higher (29.9%) at a wet site, such as Harvard Forest in the USA. Increasing soilrespiration can speed up global warming through a positive feedback mechanism