Impacts of soil conditions and light availability on natural regeneration of Norway spruce Picea abies (L.) H. Karst. in low-elevation mountain forests

& Key message Natural regeneration of P. abies (L.) H. Karst. may reach high densities in lower mountain elevations. The highest densities were found in sites with moderate light availability, with low pH, and not near the riverbank. However, age-height classes differed in the predicted magnitude of response, but were consistent in response directions. Mosses and understory species typical of coniferous forests were positively correlated with regeneration density. & Context Norway spruce Picea abies (L.) H. Karst. in Central Europe is at risk under climate change scenarios, particularly in mountain regions. Little is known about the impact of environmental factors on the natural regeneration of P. abies in lowelevation mountain forests. & Aims We aimed to assess impacts of distance from the riverbank, soil pH, and light availability on natural P. abies regeneration. We hypothesized that (1) natural P. abiesregeneration would depend on light availability and soil pH and (2) there are understory plant species which may indicate the microsites suitable for natural regeneration of P. abies. & Methods The study was conducted in the Stołowe Mountains National Park (SW Poland, 600–800 m a.s.l.). We established 160 study plots (25 m2 ) for natural regeneration, light availability, soil pH, and understory vegetation assessment

Nature 2000 and forestry: misunderstandings, achievements, challenges

Wstąpienie Polski do UE i w konsekwencji przyjęcie Dyrektyw „Siedliskowej” i „Ptasiej” oraz tworzenie Europejskiej Sieci Ekologicznej Natura 2000 spotkało się z przeważnie niechęcią leśników i ich zastrzeżeniami co do zasadności zgłaszania konkretnych obszarów do sieci Natura 2000. W latach 2006-2007 w LP została przeprowadzona powszechna inwentaryzacja przyrodnicza, poprzedzona przygotowanymi przez poszczególne RDLP bibliografiami odnośnie siedlisk i gatunków ujętych w w/w Dyrektywach UE. Wyznaczanie obszarów sieci Natura 2000 spowodowało aktywizację i wymusiło integrację działań służb ochrony przyrody, jednostek Lasów Państwowych (LP), lokalnych samorządów, organizacji pozarządowych, przyrodników i naukowców. Powszechna inwentaryzacja, oprócz pozytywnej mobilizacji ponad 7000 osób, zaowocowała utworzeniem obszernej bazy danych. Obecnie w sieci Natura 2000 znalazło się ponad 2500000 ha lasów, tworzących OSOP – obszary ptasie oraz SOOS – obszary siedliskowe. Warunki, zapewnienia odpowiedniej ochrony są znane, ale dla ich spełnienia konieczne będzie znalezienie praktycznych rozwiązań. Tak więc, niezależnie od zróżnicowanych poglądów odnośnie ilości, wielkości i lokalizacji obszarów sieci Natura 2000 leśnicy stają obecnie wobec wyzwania, jakim jest konieczność określenia zasad gospodarowania w tych obszarach zgodnie z duchem i literą Dyrektyw UE.Adoption of the “Birds” and the “Habitats” Directives that form the European Ecological Network “Nature 2000” was one of the Poland’s obligations after its joining the European Union. At the beginning, Polish foresters have expressed rather reluctant approach towards the necessity of these Directives implementation. In 2006 – 2007 the State Forests General Directorate initiated a nationwide inventory of the natural values of Polish forests. The preparatory works have been carried out in each State Forests Regional Directorate. They included very detailed query in existing bibliography as far as both species and habitats listed in the Directives were concerned. Planning of the range and composition of the Polish “Nature 2000” network elicited and integrated activities of all bodies involved, including the nature conservation boards, forest districts, local governments, NGOs, and naturalists – amateurs and researchers. In turn, the nationwide inventory that positively involved more that 7 000 persons resulted in preparing of very wide and valuable database that confirms a high biodiversity of the Polish forests and some non-forest ecosystems. At present, some 2 500 thousands hectares of the Polish forests are included into the “Nature 2000” network, either as the Special Protection Areas (SPAs – see the “Birds” Directive) or as the Special Areas of Conservation (SACs – see the “Habitats” Directive). Requirements that should be fulfilled in order to secure the protection/survival of habitats and/or plant and animal species are generally known, however the practical solutions in each individual case of concern have to be identified and implemented. Thus, despite foresters individual approaches concerning the number, size and distribution of the “Nature 2000” network areas, they became confronted with a necessity of developing the forest management rules adapted to these areas in accordance with the Directives’ premises and regulations

The structure of forest stands in theTatra National Park: The results of 2016-2017 inventory

The composition and structure of forest stands in the Tatra National Park were examined using data gathered in 2016 and 2017 from 617 circular sample plots (0.05 ha each). The diameter at breast height of all living trees, standing dead trees, snags, and wind throws was measured along with diameters and lengths of fallen logs within the plot boundaries. Tree height was measured for all living trees within the core (0.01 ha) of the sample plots. Using the obtained data, height-diameter curves were calculated for all major tree species and in the case of spruce, the height-diameter relationships were also calculated separately for each of the three elevation zones (up to 1200 m, between 1200 and 1400 m, above 1400 m). For each elevation zone and park protection zone, we also determined the volumes of live and dead trees. The volume of living trees in the Tatra National Park amounted to 259 m3/ha, which was higher than the volume of dead trees (176 m3/ha). Snags constituted the largest part of the dead wood whilst over 97% of the standing dead trees were spruce Picea abies. Among living trees, the share of spruce ranged from 81% in the low elevation zone to 98% in the middle zone. Other significant species in the lower zone were Abies alba (11%) and Fagus sylvatica (4.5%), while in the middle and upper elevation zones only Sorbus aucuparia occurred in significant numbers. Furthermore, in the lower elevation zone, Fagus sylvatica was the only species displaying significantly higher volumes in the ‘strict protection’ zone compared to the other park areas. In the ‘landscape protection’ zone, Picea abies was the most dominant species and the share of other species in the lowest elevation zones calculated based on tree density was smaller than calculated based on tree volume, indicating problems with stand conversion from spruce monoculture to mixed forest

Species composition, elevation, and former management type affect browsing pressure on forest regeneration in the Tatra National Park

Effects of ungulate pressure on the development of young generation of trees is one of the most important issues in ecology and forestry. Ungulate pressure influence on the development of natural regeneration has been also reported from several national parks. Our study on the effects of ungulate browsing on the young generation of trees was conducted on more than 500 sample plots controlled during one growing season. The overall browsing pressure ranged from 7.6% in seedlings to 20.3% in low saplings. The pressure of ungulates on the regeneration of Picea abies, the dominant species in the Tatra National Park, was by and large below 1%. Broadleaved species were browsed more frequently. The relationship between the plot altitudes and browsing intensity was statistically significant for seedlings and low saplings; at the higher altitudes, the browsing pressure was greater. There was also observed a statistically significant relationship between the type of former management and the browsing degree in seedlings; in the areas subjected to “landscape protection”, the intensity of browsing was higher when compared to strictly protected areas. Pressure exerted by ungulates on tree regeneration was very unevenly distributed, i.e. some plots were heavily browsed and many others - not browsed at all. The most affected tree species were Salix caprea and Sorbus aucuparia, although the percentage of browsed individuals rarely exceeded 50%. Other species favored by ungulates was Acer pseudoplatanus; despite the high browsing pressure, this species was present among seedlings and tall saplings, suggesting that it would be able to recruit to the tree layer. Abies alba was browsed less frequently than the deciduous trees; however, among the tall saplings it was the third most browsed species