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Waser L.T.,Swiss Federal Institute of forest | Kuchler M.,Swiss Federal Institute of forest | Jutte K.,Landesforst Mecklenburg Vorpommern | Stampfer T.,Landesforst Mecklenburg Vorpommern
Remote Sensing | Year: 2014

Forest disturbances in central Europe caused by fungal pests may result in widespread tree mortality. To assess the state of health and to detect disturbances of entire forest ecosystems, up-to-date knowledge of the tree species diversity is essential. The German state Mecklenburg-Vorpommern is severely affected by ash (Fraxinus excelsior) dieback caused by the fungal pathogen Hymenoscyphus pseudoalbidus. In this study, species diversity and the magnitude of ash mortality was assessed by classifying seven different tree species and multiple levels of damaged ash. The study is based on a multispectral WorldView-2 (WV-2) scene and uses object-based supervised classification methods based on multinomial logistic regressions. Besides the original multispectral image, a set of remote sensing indices (RSI) was derived, which significantly improved the accuracies of classifying different levels of damaged ash but only slightly improved tree species classification. The large number of features was reduced by three approaches, of which the linear discriminant analysis (LDA) clearly outperformed the more commonly used principal component analysis (PCA) and a stepwise selection method. Promising overall accuracies (83%) for classifying seven tree species and (73%) for classifying four different levels of damaged ash were obtained. Detailed tree damage and tree species maps were visually inspected using aerial images. The results are of high relevance for forest managers to plan appropriate cutting and reforestation measures to decrease ash dieback over entire regions. © 2014 by the authors.

Leinemann L.,University of Gottingen | Kahlert K.,Thuringer Landesanstalt fur Wald | Arenhovel W.,Thuringer Landesanstalt fur Wald | Voth W.,Landesforst Mecklenburg Vorpommern | Hosius B.,ISOGEN
Allgemeine Forst- und Jagdzeitung | Year: 2010

The main objective of the survey was the characterization of Hybrid-Species of the Sorbus latifolia aggr. with universal (ccmp) cpDNA markers. In total, 141 samples of 12 Sorbus species including the two ancestral species Sorbus aria and Sorbus torminalis were investigated. Beside eight botanically characterized HybridSpecies {Sorbus acutisecta, Sorbus decipiens, Sorbus heilingensis, Sorbus isenacensis, Sorbus latifolia, Sorbus multicrenata, Sorbus parumlobata, Sorbus subcordata) the species Sorbus pinnatifida and Sorbus intermedia were analysed (see Table I and Figure 1). Isozyme gene markers were applied to investigate apomictic regeneration in one species {Sorbus heilingensis) with overall 68 progenies of ten seed parents. The cpDNA analyses displayed 10 haplotypes (see Table 2). In Table 3 the haplotype frequencies within the single species are shown. Two out of a total of 10 haplotypes (S-9 and S-14) were characteristic for the ancestral species Sorbus aria and Sorbus torminals, respectively, with frequencies of about 70% each. Other haplotypes are rare in these two species. With the exception of one Sorbus latifolia tree all hybrids showed solely haplotypes of the two potential ancestral species. One of the rare haplotypes (S-22) of the ancestral species displayed frequencies higher than 50% in some of the hybrid species. Thus, a third unidentified ancestral species is possibly involved in the formation of this hybrid aggregate. The distribution of haplotypes within and between the single hybrid species indicates that hybridisation between Sorbus aria and Sorbus torminalis is possible in both directions. Each of the taxonomically distant species Sorbus pinnatifida and Sorbus intermedia showed unique haplotypes. The investigations concerning apomictic regeneration in Sorbus heilingensis revealed unexpectedly high estimates of sexual regeneration of 96% since only 4% of the progenies showed identical patterns to their particular seed parents.

The goal of this study was to estimate the need for forest liming in Mecklenburg-Vorpommern (Germany). As "reinventing the wheel" is usually pointless, seven already existing guidelines from other German regions were used. The study was based on inventory data of the national forest soil inventory program (BZE-2). The frequencies of potential sites for liming were calculated for the whole sample. Additionally, to get an overview of the most preferential sites, the frequencies for different soil type groups were calculated separately. Unfortunately the results showed a high degree of differences and contrarieties. As a result of these findings, the initial goal of estimating the need of forest liming by already existing guidelines could not been accomplished. © DLV GmbH.

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