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Mistletoe (Viscum album L.) is a semi−parasitic plant and, as long as it is not present in large quantities, it does not pose a lethal threat to trees. Due to its ability to carry out photosynthesis, its effect on the host is negligible. However, recent droughts have made heavy impact on forests and mistletoe in recent years began to appear on a larger scale in regions and in places where it has never been a threat before. For this reason, there is an urgent need to broaden our knowledge about this species. This work includes a review of the literature on the biology and ecology of mistletoe. The main purpose of this research is to analyze the methods for assessing the number of mistletoe on individual trees and in the stands as well as to prepare new method adapted to Polish conditions. New method that was proposed is based on random sample plots, each consisting of 15 trees on which impact of mistletoe is assessed. On every sample plot the mistletoe occurrence, location in the crown, estimate of the percentage within the crown and the number of mistletoe on a tree is assessed. In addition, for further analysis, information on stand (forest habitat type, site index) as well as measured trees (age, diameter, Kraft class, crown length, loss of assimilation apparatus, crown type) levels is recorded.
In this paper, we present problems with the management of the forests acquired by the State Forests from the State Land Fund. This was particularly an issue in forest districts with a significant share of private forests, e.g. eastern part of Poland. The problem becomes more and more valid because of the latest amendment of the Forest Act in 2016. It gives the State Forests the right of the first purchase of private forests attributed to sale. They may receive forest stands that will generate specific economic problems related to care, conservation, felling maintenance, etc. These are mostly stands with typical features of private forests, resulting from abandoning economic operations, selective acquisition, as well as from the size, shape and neighbourhood of the plots. This study presents the characteristics of almost 2,000 tree stands acquired from the State Land Fund between 1992−2016 by the Siedlce Forest District (SFD), which is a part of the Regional Directorate of the State Forests in Warsaw. SFD has low forest cover (18%), a strong fragmentation of forest complexes and a very large share of private forests (over 75%). The analysis was based primarily on the descriptions of forest stands and the quantitative and qualitative characteristics, presenting at the same time the problems that SFD has with conducting rational forest management in acquired plots. The current status of the forests transferred from the State Land Fund was assessed as unsatisfactory. The main problems in local conditions are: (i) inadequate fixation in acquired parcels next to private forests (difficulty in locating treatments and custody over the State property), (ii) depleted tree stands, (iii) inadequate parcels (too narrow) and (iv) complications related to co−ownership of parts seized plots. The need to carry out joint−assembly works (mainly land consolidation) or to introduce land communities that would facilitate the management of these forests was demonstrated.
Nowadays in forestry, we observe an increase in threats that rise the uncertainty and risk of the forest management. This is caused, inter alia, by increasing intensity of forest and environmental damage as well as by the conflict of expectations for the use of forest resources. As a result, there is a problem of achieving the goals of sustainable development and adaptation of the forest ecosystems to new challenges. The aim of the presented study was to assess the regional variety of the need and the urgency of stands conversion. The feature was determined for all stands of the State Forests older than 20 years. Three assessment criteria were selected: (A) silvicultural target (compatibility of the species composition with the planned one), (B) stands stability (resultant from 5 auxiliary sub−indices), and (C) stock level (including 2 auxiliary sub−indices). The majority of stands has consistent species composition (over 60% in total), however only a small fraction of stands was found with a species composition incompatible with the planned one (average 6.34%). Stands with medium stability accounted for about 70%, while those with poor growing stock status make up about 70% of stands under analysis. The regional diversification of the needs for stands reconstruction seems to be strongly correlated with the incompatibility of stand’s species composition with habitat conditions. The largest fraction of stands requiring conversion was observed in Wrocław, Kraków and Katowice regional directorates of the State Forests. This situation may change in the future due to dynamic changes resulting from modifications of the climate and the deterioration of health condition of dominant Scots pine stands in central and north parts of Poland. Private forests were not taken into consideration in this research. It may impact the overall picture in regions of the high share of private forest ownership.
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