| dc.description.abstract | This study investigates the climate-growth relationships of Norway spruce (Picea abies) across a north-south gradient in Norway. The research encompasses ten forest sites spanning 325 kilometres from Stor-Elvdal (north) to Aremark (south), within the boreal and southern boreal vegetation zones. Tree-ring analyses of 125 trees revealed distinct regional differences in radial growth responses to temperature and precipitation.
From 1960 to 2022, mean temperatures significantly increased at all sites, extending the thermal growing season (TGS) by an average of 18 days. The most substantial warming trends occurred in the Mid and North regions, where average annual temperatures rose by up to 3°C. Precipitation trends varied, with mild increases in the South and Mid regions, while the North region remained relatively stable. The climate-growth correlations revealed distinct regional patterns: in northern sites,
June temperatures had the strongest correlation with Basal Area Increment (BAI), highlighting the thermal limitations of radial growth at these latitudes. In contrast, southern plots demonstrated a greater sensitivity to July precipitation, indicating more hydrological sensitivity. BAI analyses indicated a general stabilization or increase in growth in northern plots. Conversely, southern plots experienced a marked decline starting around 2010, persisting at least until 2019. Overall, the results confirm that northern forest stands are primarily limited by temperature, whereas southern forests rely more on precipitation for growth. Thus,
improving our understanding of where the boundaries between temperature and precipitation limitations lie. As average temperatures continue to rise, these constraints may shift, underscoring the importance of monitoring the impact on forest ecosystems. Understanding these regional differences in climatic sensitivity is crucial for developing adaptive forest management strategies in the face of climate change.
Future research should incorporate a more holistic approach, utilizing additional data and extending the study to more sites and species to refine our understanding of climate impacts on boreal forests. | |
