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1
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Ocena zmian w drzewostanie sosnowym na gruncie porolnym po 30 latach od wykonania pierwszych ciec pielegnacyjnych bez zabiegu ochronnego przeciw hubie korzeni

100%
Sierota Z., Malecka M.
Sylwan
|
2003
|
tom 147
|
nr 12
19-26
2

Zmiany drzewostanow swierkowych objetych ochrona scisla w Wigierskim Parku Narodowym

84%
Lozinski J.
Prace Instytutu Badawczego Leśnictwa. Seria A
|
2002
|
nr 1[926-930]
53-74
3
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Zmiany zachodzące w drzewostanach Bieszczadów

84%
Dmyterko E., Bruchwald A.
Sylwan
|
2018
|
tom 162
|
nr 05
The aim of the study was to analyse (on the basis of the data from the State Forests Information System) the changes occurring in the Bieszczady forests in the period of 2007−2016. One of the processes taking place in the study area is the withdrawal of grey alder stands and the appearance of natural regeneration of mainly beech and fir, and in a smaller proportion spruce (fig. 1). Another natural process is the encroachment of fir and beech under the canopy of pine stands, which is favoured by fertile habitats that meet the ecological requirements of these two tree species. As a result of economic activity supporting these processes, alder and pine stands are being rebuilt relatively quickly, turning into fir or beech stands, and sometimes into mixed stands with the participation of other tree species, including spruce (fig. 1). The decline of spruce stands occurs on the dominant area in Poland: in Beskid Śląski and Beskid Żywiecki, the Kaszuby Forest or the Białowieża Forest. The main causes of this process are abiotic and biotic factors, including frequent droughts causing the lowering of the groundwater level and insect outbreaks, especially of bark beetles. The proportion of spruce in the Bieszczady Mountains is relatively small (about 10%), and the high fertility of the habitats compensates, to some extent, the relatively high moisture requirements of this tree species and probably these factors determined the lack of decline of spruce stands in the analysed area. In the last 10 years, the average age of forests in the Bieszczady Mountains increased from 77 to 83 years (tab. 2), mainly as a result of too low volume of harvested timber (fig. 3). Comparing the total harvested volume with the volume of allowable cut determined by the stand growth model, the harvest of the wood raw material was understated by about 25%. The aging of forests is also confirmed by changes in stands in age classes (fig. 2). The aging of the Bieszczady forests is correlated with the process of increasing the threat to these forests by wind (figs. 4−5). The wind damage risk factor increased over the next 10 years in the two highest threat level, and thus the area of threatened stands increased. The forest threat measure in the Bieszczady forests increased in general as well as in individual forest districts (fig. 6). The forests in two of these districts are currently among the most threatened in Poland.
4

Przemiany lasów w strefie ochrony czynnej w Tatrzańskim Parku Narodowym pod wpływem działalności człowieka oraz procesów naturalnych

67%
Krzan Z., Maczka T.
Parki Narodowe i Rezerwaty Przyrody
|
2015
|
tom 34
|
nr 4
5
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Zmiany zachodzące w lasach Ziemi Kłodzkiej w latach 2001-2017

67%
Dmyterko E., Bruchwald A.
Sylwan
|
2019
|
tom 163
|
nr 08
The aim of the study was to assess the changes occurring in the forests of the Kłodzko Region in the recent period (2001−2017), with particular emphasis on the species composition of the stands, their share in age classes and the structure of harvested timber, including live trees, deadwood, wind−broken and wind−fallen trees. The Kłodzko Region located in the Sudety Mountains (SW Poland) covers the forests of four forest districts: Lądek−Zdrój, Międzylesie, Bystrzyca Kłodzka and Zdroje. The declining share of spruce stands (from 83.5% in 2001 to 75.5% in 2017) and the increasing share of beech and larch as well as sycamore stands indicate that these forests are systematically rebuilt. The average age of the stands is very high (81 years). The share of young (<20 years old ) stands is low (only 5%), while those older than 100 years constitute about 35%. The 21st century saw a serious damage to the investigated forests caused by frequent strong winds and long−lasting droughts in the growing seasons. The three hurricanes that took place in the analysed period were the cause of the removal of 1.1 million m³ of timber in the form of wind−broken and wind−fallen trees. The drought in the growing season in 2015 resulted in the salvage harvest of deadwood with a total volume of 1.6 million m³, which corresponds to the volume of four annual allowable cuts determined for the undisturbed growth conditions of trees in the area under research. Using the wind damage risk model, the threat measure Ms reaching a value of above 40 was calculated for the forests of the Kłodzko Region, which are currently among the most threatened in Poland. This threat results mainly from the high share of spruce stands in older age classes with high average height and gaps after previous hurricanes as well as from a large area of stands located at high elevations.
6

Wpływ wieloletnich zmian drzewostanu na obecną strukturę przestrzenną i skład gatunkowy naziemnej warstwy mszystej w płacie zaspołu Abietetum polonicum

67%
Maciejewski Z., Zubel R.
Ochrona Środowiska i Zasobów Naturalnych
|
2009
|
nr 38
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