O. Janne Kjønaas
Seniorforsker
Forfattere
Johan Asplund Jenni Nordén O. Janne Kjønaas Rieke Lo Madsen Lisa Fagerli Lunde Tone Birkemoe Eivind Kverme Ronold Milda Norkute Ulrika Jansson Damian P. Karlsen Anne Sverdrup-Thygeson Inger Skrede Ine-Susanne Hopland Methlie Sundy Maurice Ulrik G. Botten Regine Krok Håvard Kauserud Line NybakkenSammendrag
The history of forestry in Fennoscandia spans five centuries, with clear-cutting being the dominant practice since the mid-20th century. This has led to a significant transformation of the forest landscape. In this study we investigated long-term effects of clear-cutting on forest structure and dead wood volumes. We established twelve pairs of spruce forest sites in southeastern Norway, each pair constituting of a mature, previously clear-cut stand and its near-natural counterpart with similar edaphic factors. The near-natural stands had 2.8 times higher volumes of dead wood and a larger proportion of dead wood in late stages of decay. The near-natural stands had on average 36.8 ± 9.1 m3 ha− 1 of downed dead wood and 24.1 ± 6.2 m3 ha− 1 of standing dead wood. Corresponding numbers for the previously clear-cut stands were 10.2 ± 2.8 m3 ha− 1 and 11.9 ± 3.7 m3 ha− 1 . Forests with lower volumes of dead wood often also had lower connectivity of old spruce forests, which potentially have further negative effects on biodiversity. Furthermore, near-natural stands displayed greater tree size heterogeneity, resulting in a wider variation in light conditions. While no difference was observed in living tree volume, we found only weak evidence for higher basal area in the previously clear-cut stands, which had a higher stem density with more slender stems and shorter crowns. Our findings suggest that managed forests do not develop structures typical of near-natural forests before they become mature for logging. We stress the importance of a thorough site selection for studies of management effects, as forest management history may be confounded with productivity and other edaphic factors. Experimental designs like ours are vital for testing how differences in structure and deadwood volumes, driven by forest management, translate into variations in biodiversity, carbon sequestration and ecosystem functioning in future studies Coarse woody debris Clear-cutting forestry Norway spruce Structural heterogeneity
Forfattere
Sunil Mundra Dinesh Sanka Loganathachetti Håvard Kauserud Anna Maria Fiore-Donno Tonje Økland Jørn-Frode Nordbakken O. Janne KjønaasSammendrag
Large-scale replacements of native birch with spruce have been carried out in Western Norway for economic reasons. This tree species shift potentially affects biotic components such as the eucaryome, consisting of microscopic animals (Metazoa), protists and fungi, which are key players in the functioning of forest ecosystem. The impact on the belowground eukaryome and its interactions with vegetation and soil properties is not well assessed. We examined the impact of replacing native birch with Norway spruce plantations on the eukaryome of the boreal forest floor in Western Norway using 18S rDNA metabarcoding. The tree species shift from birch to spruce had significant impacts on the eukaryome at both taxonomic (Metazoa) and functional categories (phagotrophs, phototrophs, parasites and osmotrophs). The distinct differences in eukaryome communities were related to changes in understorey vegetation biomass and soil chemistry following the tree species shift. This had a negative effect on eukaryome richness, particularly affecting phagotrophs and parasites, while the opposite was observed for osmotroph richness. Our results indicated that the spruce plantations altered the eukaryome communities and their food-web patterns compared to what was found in the native birch forest soil. This information should be taken into consideration in forest management planning.
Forfattere
Eivind Kverme Ronold Sundy Maurice Vilde Åvesland Torp Celina Alexandria Kostich-Nilsen Ine-Susanne Hopland Methlie Frida Schmidt Markus Osaland Fjelde Ella Thoen Anders Kristian Krabberød Johan Asplund O. Janne Kjønaas Jenni Nordén Rune Halvorsen Tone Birkemoe Line Nybakken Inger Skrede Håvard KauserudSammendrag
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