Forest Litter Interception Model for a Sessile Oak Forest

Abstract Models that describe hydrological processes in forests may help to estimate the consequences of forestry interventions or of climate change. The authors employed a hydrologic model for estimation of forest litter interception of a middle-aged sessile oak (Quercus petraea) stand. Antecedent water content and the storage capacity of the forest litter were the main parameters of the model. The antecedent water content of the litter was estimated by the daily precipitation and temperature data, collected in Hidegviz Valley research catchment in a three year measurement period (2006-2008). The measurements were done by an instrument we developed ourselves, where the undisturbed forest litter samples were enclosed in frames and measured in daily time steps.</jats:p

Soil Erosion Analysis in a Small Forested Catchment Supported by ArcGIS Model Builder

To implement the analysis of soil erosion with the USLE in a GIS environment, a new workflow has been developed with the ArcGIS Model Builder. The aim of this four-part framework is to accelerate data processing and to ensure comparability of soil erosion risk maps. The first submodel generates the stream network with connected catchments, computes slope conditions and the LS factor in USLE based on the DEM. The second submodel integrates stream lines, roads, catchment boundaries, land cover, land use, and soil maps. This combined dataset is the basis for the preparation of other USLE-factors. The third submodel estimates soil loss, and creates zonal statistics of soil erosion. The fourth submodel classifies soil loss into categories enabling the comparison of modelled and observed soil erosion. The framework was applied in a small forested catchment in Hungary. Although there is significant deviation between the erosion of different land covers, the predicted specific soil loss does not increase above the tolerance limit in any area unit. The predicted surface soil erosion in forest subcompartments mostly depends on the slope conditions.TÁMOP 4.2.1/B-09/KONV-2010–0006TÁMOP 4.2.2. B–10/1–2010–0018EU/European Social Fun

Észak-alföldi akác, nemesnyár és kocsányos tölgy erdőállományok hatása a talajvízre és ionforgalomra

Az alföldi erdőállományok hidrológiai folyamatokban betöltött szerepe a mai napig vita tárgya. Ennek egyik oka a folyamatokban szerepet játszó, nagy számú és variabilitású lokális tényező.Egy 2012-óta zajló kutatássorozat összesen 108 mintaponton, egyszeri mintavételezés, állományfelmérés és talajvíz monitoring segítségével vizsgálja az erdőállományok talajvízszintre és a talaj ionforgalomára gyakorolt hatását.Az eredmények általánosságban az állományok alatti talajvíz depresszió és az ionakkumuláció tekintetében is megerősítették a hipotézisben megfogalmazottakat. Ugyanakkor rávilágítottak arra is, hogy fafajok eltérő vízfelvételi stratégiája, illetve az egyéb lokális tényezők (topográfiai elhelyezkedés, talajtextúra) alapvetően befolyásolják a lezajló folyamatokat.A fentiekből következik, hogy az erdőállományok talajvízre gyakorolt hatását, nem helyes kizárólag azok nagyobb mértékű párologtatása alapján megbecsülni, ahhoz szükséges a tényezők komplex megközelítése. Ebben lehet lehet hasznos eszköz a talajvíz monitoringja és a talajban történő iontranszport vizsgálata is

Soil erosion analysis in a small forested catchment supported by ArcGIS Model Builder

To implement the analysis of soil erosion with the USLE in a GIS environment, a new workflow has been developed with the ArcGIS Model Builder. The aim of this four-part workflow is to accelerate data processing and to ensure comparability of soil erosion risk maps. The first submodel generates the stream network with connected catchments, computes slope conditions and the LS factor in USLE based on the DEM. The second submodel integrates stream lines, roads, catchment boundaries, land cover, land use, and soil maps. This combined dataset is the basis for the preparation of other USLE-factors. The third submodel estimates soil loss, and creates zonal statistics of soil erosion. The fourth submodel classifies soil loss into categories enabling the comparison of modelled and observed soil erosion. The workflow was applied in a small forested catchment in Hungary. Although there is significant deviation between the erosion of different land covers, the predicted specific soil loss does not increase above the tolerance limit in any area unit. The predicted surface soil erosion in forest subcompartments mostly depends on the slope conditions

Groundwater uptake of different surface cover and its consequences in great Hungarian plain

Forest cover in Hungary has increased from 1.1 to 2.0 million hectares during the last century. The EU (European Union) promotes further afforestation; thus, 15,000–18,000 ha are being forested each year, mainly in the Hungarian Great Plain. In terms of species used for afforestation, poplar plantations are preferred over native oak woodlands

Észak-alföldi akác, nemesnyár és kocsányos tölgy erdőállományok hatása a talajvízre és ionforgalomra

Az alföldi erdőállományok hidrológiai folyamatokban betöltött szerepe a mai napig vita tárgya. Ennek egyik oka a folyamatokban szerepet játszó, nagy számú és variabilitású lokális tényező.Egy 2012-óta zajló kutatássorozat összesen 108 mintaponton, egyszeri mintavételezés, állományfelmérés és talajvíz monitoring segítségével vizsgálja az erdőállományok talajvízszintre és a talaj ionforgalomára gyakorolt hatását.Az eredmények általánosságban az állományok alatti talajvíz depresszió és az ionakkumuláció tekintetében is megerősítették a hipotézisben megfogalmazottakat. Ugyanakkor rávilágítottak arra is, hogy fafajok eltérő vízfelvételi stratégiája, illetve az egyéb lokális tényezők (topográfiai elhelyezkedés, talajtextúra) alapvetően befolyásolják a lezajló folyamatokat.A fentiekből következik, hogy az erdőállományok talajvízre gyakorolt hatását, nem helyes kizárólag azok nagyobb mértékű párologtatása alapján megbecsülni, ahhoz szükséges a tényezők komplex megközelítése. Ebben lehet lehet hasznos eszköz a talajvíz monitoringja és a talajban történő iontranszport vizsgálata is

Groundwater uptake of different surface cover and its consequences in great Hungarian plain

Abstract Introduction Forest cover in Hungary has increased from 1.1 to 2.0 million hectares during the last century. The EU (European Union) promotes further afforestation; thus, 15,000–18,000 ha are being forested each year, mainly in the Hungarian Great Plain. In terms of species used for afforestation, poplar plantations are preferred over native oak woodlands. The groundwater uptake of trees can be a significant water balance element of forested areas in shallow groundwater environments within the Hungarian Great Plain. Forests can cause water table depressions and subsurface salt accumulation in areas with negative water balance. This study examined the hydrological impact of forest cover in the Hungarian Great Plain. Within the framework of this research, climatic water balance, water table depth and salinity, subsoil layering, tree species and stand age were analysed as influencing factors. This paper compares the effect which an oak forest, a poplar plantation and a pasture have on groundwater uptake and salt accumulation. Results The water table level was roughly 0.4–0.5 m lower beneath the oak forest and the poplar plantation than it was beneath the pasture. Forest groundwater use was 1.5–2 times higher than that of grassland. Groundwater uptake of oak forest was greater than that of poplar plantation during the monitoring period. Salt accumulation, which shows water use in the longer run, was slightly higher for poplar in deeper layers. Conclusions The greater amount of groundwater used by trees does not lead to a higher salt uptake as only a slight accumulation of salt was measured beneath the forests. Overall, hybrid poplar was slightly less favourable than native oak when considering salinization effects. However, even greater groundwater uptake by trees over longer timescales could cause more significant salt accumulation under pronounced drought conditions due to climate change

Factors controlling the daily change in groundwater level during the growing season on the Great Hungarian Plain: a statistical approach

The phenomenon of diurnal fluctuation in the groundwater level (GWL) often reflects the water uptake by plants. The rate of evapotranspiration from the groundwater (ETgw) can be calculated from the daily rate of change in GWL, but several factors may influence the vertical groundwater dynamics. The occurrence of diurnal fluctuation and the daily rate of change in GWL were determined in 20 monitoring wells on the Great Hungarian Plain with different vegetation cover (Quercus robur L., Robinia pseudoacacia L., Populus × euramericana and unforested control sites) and with differences in the water table depth (WTD) and in soil and salinity characteristics. ETgw was calculated for eight selected sites. Forest vegetation significantly increased the occurrence of diurnal fluctuation (8 out of 11 cases), and the mean daily change in GWL multiplied by the specific yield (S y) was 2.2 times higher for forest sites than for the unforested control sites. The median daily change in GWL showed a significant negative correlation with S y, where the vegetation effect was manifested as ETgw-induced diurnal fluctuation. A significant correlation was obtained at each monitoring well between the meteorological parameters controlling the evaporative demand and the daily rate of change in GWL. A reduction in groundwater uptake after rainfall events and increasing groundwater consumption during dry periods were also revealed. A significant positive correlation was found at some study sites between the daily change in GWL and WTD, and between ETgw and the leaf area index (LAI). Mean ETgw was 8.2 mm day−1 for oak stand and 0.4 mm day−1 for black locust stand, while it ranged from 1.7 to 6.0 mm day−1 for the four poplar stands, which may reflect the variability in water demand, LAI, groundwater and soil characteristics