{"id":113936,"date":"2026-04-12T02:24:00","date_gmt":"2026-04-12T00:24:00","guid":{"rendered":"https:\/\/www.sonnenseite.com\/?p=113936"},"modified":"2026-04-10T11:24:28","modified_gmt":"2026-04-10T09:24:28","slug":"why-treelines-dont-simply-rise-with-the-climate","status":"publish","type":"post","link":"https:\/\/www.sonnenseite.com\/en\/science\/why-treelines-dont-simply-rise-with-the-climate\/","title":{"rendered":"Why treelines don\u2019t simply rise with the climate"},"content":{"rendered":"\n

A global study by the University of Basel reveals a surprising picture: while 42 percent of treelines worldwide are shifting upslope, 25 percent are retreating. This seemingly contradictory trend involves more than just warming. Climate change and human land use are interacting.<\/a><\/a><\/a><\/a><\/p>\n\n\n\n

The climate crisis is pushing treelines upward, at least this is the common assumption. But a new global study paints a more complex picture: 42 percent of treelines shifted upslope between 2000 and 2020, a quarter shifted downhill during the same period.<\/p>\n\n\n\n

The findings show that temperature alone does not explain these changes. Human interventions in the landscape, such as land-use changes, significantly influence how treelines develop. The results of the study were recently published in the International Journal of Applied Earth Observation and Geoinformation<\/em>.<\/p>\n\n\n\n

The researchers examined shifts in the actual treeline using satellite data and compared this with the potential treeline; that is, where trees could theoretically grow based on climate.<\/p>\n\n\n\n

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While climate change is clearly the cause of glacier retreat, the reasons behind treeline positions are complex.<\/h3>\n\n\n\n

Sabine Rumpf<\/p>\n<\/blockquote>\n\n\n\n

The study sheds light on processes that unfold over decades. \u201cThe shift of treelines occurs slowly, it would take a lifetime to fully grasp the changes,\u201d says Dr. Mathieu Gravey of the Institute for Interdisciplinary Mountain Research at the Austrian Academy of Sciences (\u00d6AW).<\/p>\n\n\n\n

Temperature isn\u2019t everything<\/h4>\n\n\n\n

Treelines are considered a particularly vivid symbol of climate change. But this impression falls short, emphasizes Prof. Dr. Sabine Rumpf from the Department of Environmental Sciences at the University of Basel. \u201cWhen you talk to people about climate change, there are usually two images that come to mind: glacier retreat and the shifting of treelines. Treelines are often attributed solely to climate change. But it\u2019s not that simple. While climate change is clearly the cause of glacier retreat, the reasons behind treeline positions are complex,\u201d says Rumpf.<\/p>\n\n\n\n

While temperature fundamentally determines where trees can potentially grow,the actual position of treelines, and how it changes, depends heavily on human use.<\/p>\n\n\n\n

In the European Alps, for example, pastures at high elevations are increasingly abandoned. Where grazing declines, trees can move in again and the actual treeline shifts upward. \u201cIt\u2019s not about whether the alpine region is being used, but how that land use is changing,\u201d explains Rumpf. \u201cThe more alpine pastures are abandoned, the more trees grow back in places where they could have been all along.\u201d<\/p>\n\n\n\n

The study shows that, globally, the more a region has been used in the past, the greater the influence of land use changes on current treeline dynamics. Temperature and land use often have an equally strong impact.<\/p>\n\n\n\n

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It is difficult to distinguish between human and natural influences and triggers.<\/h3>\n\n\n\n

Tianchen Liang<\/p>\n<\/blockquote>\n\n\n\n

The study shows that, globally, the more a region has been used in the past, the greater the influence of land use changes on current treeline dynamics. Temperature and land use often have an equally strong impact.<\/p>\n\n\n\n

Other disturbances such as fires also play a role. On a global scale, 38 percent of downward shifts of treelines can be linked to fire events. \u201cFires are an example of natural disturbances,\u201d says the study\u2019s first author, Dr. Tianchen Liang from the University of Basel. \u201cBut many wildfires, such as those in North America, can no longer be completely separated from human influences. Climate change and other human activities are increasing their frequency and scale.\u201d This highlights the complexity of these interactions: \u201cIt is difficult to distinguish between human and natural influences and triggers.\u201d<\/p>\n\n\n\n

A piece of the puzzle in understanding climate change<\/h4>\n\n\n\n

According to the researchers, the treeline is an important but often misunderstood signal of global change. \u201cThe shifting of treelines is one piece of a large puzzle for understanding the impact of climate change,\u201d says Mathieu Gravey.<\/p>\n\n\n\n

\u201cBut their significance extends beyond science,\u201d says Sabine Rumpf. \u201cTreelines are a striking example of how we, as humans, are changing our environment, directly through land use and indirectly through the consequences of human-induced climate change.\u201d<\/p>\n\n\n\n

Many global environmental changes are abstract and difficult to grasp. \u201cOften, the consequences of our actions are very far removed from what we do in our daily lives. We make decisions in our private lives or at the polls, but the consequences aren\u2019t immediately visible,\u201d says Rumpf. \u201cIt\u2019s extremely difficult to see the effects of our own decisions.\u201d Treelines are an exception. \u201cThey are one of the few changes that are intuitively understandable. In photos from the past and present, you can immediately see how the landscape has changed.\u201d<\/p>\n\n\n\n

This is why it is important to interpret treelines correctly. They respond not only to rising temperatures but to a complex interplay of climate change, land use, and natural disturbances such as fire. The study shows that anyone who wants to understand the consequences of global change must take into account both direct human interventions, such as changes in land use, and climatic changes, which are also caused by human activities. Treelines are thus not merely a thermometer of warming, but a visible expression of multifaceted global changes.<\/p>\n\n\n\n