Exploring Fall and Winter's Hidden Effects on Forest Biodiversity

"A clear difference between summer and winter that we see," Hedwall explains, "is that in summer, both deciduous and coniferous trees affect the forest microclimate similarly. But after leaf fall, deciduous trees have very little effect, while conifers help keep the forest interior warmer than outside." This shift affects understorey plants, whose survival is tied to temperature and light conditions under the canopy.

Unique Challenges in Northern Sweden

Comparing northern Sweden’s forests to warmer regions, Hedwall notes that northern forests, being more open, are less effective at buffering temperature changes. This makes them more vulnerable to climate events like heatwaves, highlighting the need for adaptive forest management.

Supporting Biodiversity Under Climate Change

Hedwall’s work on plant-pollinator interactions provides essential data to support biodiversity, showing that tree species, forest density, and age directly influence forest understorey and pollinators. “In managed forests, these factors are shaped by management decisions, so forest managers play a key role in enhancing ecosystem resilience to climate change,” he says. He suggests that managers focus on diverse tree species, such as pines or deciduous trees, to better support pollinator populations.

Preparing for the Future

Hedwall emphasizes that fall and winter are ideal times for forest owners to plan for biodiversity, as these seasons lead into spring regeneration efforts. “The decisions we make today,” he concludes, “from tree selection to forest management practices, shape our forests' resilience for the future.”