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NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.

2024

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Sammendrag

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.

Sammendrag

Biochar is a recalcitrant carbon-rich solid produced by pyrolysis of organic residues, and its application to soil is considered a promising approach to mitigate climate change, as biochar resists decomposition to readily contributes to soil carbon (C) sequestration. The IPCC provides a basis for future national-scale accounting of the changes in soil C stocks following biochar application to cropland soils. The IPCC Tier 1 approach for biochar is based on fixed emission factors to estimate biochar C sequestration. In contrast, the Tier 2 approach allows countries to use local emission factors and climate data to calculate the contribution of biochar to soil C sequestration. Accurate accounting of biochar C sequestration is essential for ensuring the credibility of C offsetting projects, as well as providing incentives for implementing biochar in C credit schemes, calling for comparative analyses of the different biochar Tier approaches. Here we retrieved biochar samples from local producers and measured their H/Corg to estimate the persistence of biochar in Norwegian croplands post application. Various feedstocks were considered, including forest residues, woody wastes, manure, sludge, and straw. For all biochar samples, the 100-year stable C fraction was calculated at ≥ 0.945, thus exceeding the default Tier 1 value (0.8). Biochar sourced from woody- and forestry residues had a Corg content above the default Tier 1 value (0.77). Based on this and data about national feedstock supplies, we compared the theoretical potential of biochar soil C sequestration to mitigate climate change in Norway, using the IPCC Tier 1 and Tier 2 approaches. Biochar C sequestration in soil was calculated at 0.79 Tg CO2-eq yr−1 and 0.92 to 0.96 Tg CO2-eq yr−1, respectively for the Tier 1 and Tier 2 approaches, thus, underlining that the choice of IPCC Tier approach can have a large impact on the estimated mitigation potential of biochar.

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Sammendrag

Tanzania dedicates a substantial proportion (38%) of its territory to conservation, with a large number of Protected Areas (PAs) managed under various regimes. Nevertheless, the country still experiences high rates of deforestation, which threaten the ecological integrity and socio-economic benefits of its forests. We utilized the Global Forest Change Dataset (2012–2022) and implemented a Propensity Score Matching (PSM) approach followed by a series of binomial logit regression modeling. Our objectives were to evaluate (1) the likelihood of PAs in avoiding deforestation compared with unprotected forest landscapes, (2) the variability in effectiveness among the different PA management regimes in avoiding deforestation, (3) evidence of leakage, defined here as the displacement of deforestation beyond PA boundaries as a result of protection inside PAs. Our findings reveal that, despite ongoing deforestation within and outside of PAs, conservation efforts are, on average, three times more likely to avoid deforestation compared with unprotected landscapes. However, the effectiveness of avoiding deforestation significantly varies among the different management regimes. National Parks and Game Reserves are nearly ten times more successful in avoiding deforestation, likely because of the stringent set of regulations and availability of resources for implementation. Conversely, Nature Forest Reserves, Game Controlled Areas, and Forest Reserves are, on average, only twice as likely to avoid deforestation, indicating substantial room for improvement. We found little evidence of the overall leakage as a consequence of protection. These results highlight the mixed success of Tanzania’s conservation efforts, suggesting opportunities to enhance the effectiveness of many less protected PAs. We conclude by proposing potential strategic pathways to enhance further the climate and ecosystem benefits of conservation in Tanzania.