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Abstract: Analizirali smo možnosti zaznavanja drevesnih vrst v okviru Monitoringa gozdov in gozdnih ekosistemov (MGGE) s poudarkom na manjšinskih in tujerodnih drevesnih vrstah ter možnosti zaznavanja razlik v pestrosti drevesnih vrst med posameznimi ekološkimi regijami. Zaznavanje minoritetnih in tujerodnih drevesnih vrst bi lahko izboljšali z obsežnejšim šifrantom drevesnih vrst, katerega dopolnitve smo predlagali. Take drevesne vrste bi zajeli z večjo verjetnostjo pri gostejši vzorčni mreži od obstoječe (4 km % 4 km). Opozorili smo tudi na pomen pravilne determinacije drevesne vrste na vzorčni ploskvi. V okviru MGGE smo ugotovili razlike v pestrosti drevesnih vrst med ekološkimi regijami; kot najpestrejša se je pokazala submediteranska ekološka regija.
Keywords: monitoring gozdov, gozdna inventura, seznam drevesnih vrst, manjšinske drevesne vrste, tujerodne drevesne vrste, pestrost drevesnih vrst, tree species diversity, non-native tree species
Published in DiRROS: 02.05.2020; Views: 2539; Downloads: 749
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Abstract: Tree ring eccentricity was used to reconstruct landslide activity in the last 138 years in the Urbas landslide located at Potoška planina in the NW part of the Karavanke Mountains, Slovenia. The research was based on the dendrochronological sampling of Norway spruce (Picea abies (L.) Karst.) in areas of varying landslide intensity. Analysis of a sudden change in the eccentricity index of 82 curved trees concluded that there were 139 growth disturbances and 16 landslide reactivations between 1880 and 2015, with a landslide return period of 8.5 years. Using lidar data, changes in the surface of the digital terrain model (DTM) were compared with changes in the eccentricity index of trees at the same location in the period 2014-2017. On the basis of temporal changes in the eccentricity index and by using spatial interpolation, landslide activity was reconstructed for the period 1943%2015. During this period, landslide intensity increased in the central part of the landslide. Although categorization into seven categories of different stem curvature was proposed, no distinction between categories with respect to their eccentricity index was found.
Keywords: landslide activity, dendrogeomorphology, tree ring eccentricity, eccentricity index, digital terrain model, spatial interpolation
Published in DiRROS: 20.02.2020; Views: 2022; Downloads: 1427
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Abstract: An extended European tree-ring network was compiled from various sources of tree-ring data from Europe, northern Africa and western Asia. A total of 1860 tree-ring chronologies were used to compare correlation coefficients calculated with aggregated day-wise and month-wise mean temperature, sums of precipitation and standardised precipitation-evapotranspiration index (SPEI). For the daily approach, climate data were aggregated over periods ranging from 21 to 365 days. Absolute correlations calculated with day-wise aggregated climate data were on average higher by 0.060 (temperature data), 0.076 (precipitation data) and 0.075 (SPEI data). Bootstrapped correlations are computationally expensive and were therefore calculated on a 69.4% subset of the data. Bootstrapped correlations indicated statistically significant differences between the daily and monthly approach in approximately 1% of examples. A comparison of time windows used for calculations of correlations revealed slightly later onset and earlier ending day of the year for the daily approach, while the largest differences between the two approaches arise from window lengths: Correlations calculated with day-wise aggregated climate data were calculated using fewer days than the monthly approach. Differences in the onset and ending dates of periods for the daily and monthly approaches were greater for precipitation and SPEI data than for temperature data.
Keywords: tree rings, dendroclimatology, tree-ring network, daily climate data, climate-growth relationships, dendroTools
Published in DiRROS: 21.08.2019; Views: 2352; Downloads: 1099
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Abstract: This paper presents results from a comparison of wholewood and cellulose carbon and oxygen isotope ratios for four UK tree species. These species occur within the historic buildings archive as both primary and supplementary construction materials and have been used to reconstruct the climate of the past. New advances in the application of stable isotopes have widened the scope of the isotope approach, but require the time-consuming purification of cellulose. Comparison of the oxygen and carbon isotope signals preserved in the wood and cellulose components confirms and builds upon previous research in this field and provides additional insight into the covariance of these two sample types between species, an
Keywords: stable isotopes, tree ring, dendrochronology, dendroclimatology
Published in DiRROS: 04.02.2019; Views: 5371; Downloads: 3469
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Abstract: In this case study, set in south-west Slovenia, the feasibility of reconstructing green water (the combined amount of evaporated and transpired water in trees and available in the soil) was investigated. In a simplifed scheme, the amounts of green water were calculated as the diference between precipitation and discharge of the Rižana river. Based on the methods of dendroclimatology, the climate signal was tested on black pine (Pinus nigra Arnold) trees growing in the south-western part of the Rižana watershed near the Slovenian sea coast. Results showed that the measured tree-ring parameters of tree-ring width and density are strongly dependent on the amount of green water. The strongest correlation was between available green water in the period May-August and tree-ring width (r=0.61) and latewood width (r=%0.64) (both n=46, p<0.001). The climate signal is signifcant and stable through time, which enabled the reconstruction of green water data into the period before instrumentally measured data. Green water data from the May-August period were extended from 1966 back to 1937 using tree-ring width, and back to 1940 using latewood width. With additional coring of older trees and the extension of existing chronologies, even longer reconstructions could be developed.
Keywords: tree-ring width, tree-ring density, dendrochronology, dendroclimatology, reconstruction
Published in DiRROS: 18.04.2018; Views: 2885; Downloads: 1709
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