The climate crisis is shifting the seasons: the fruit blossom is coming BR-Research earlier and earlier. But despite global warming, the blossoms could freeze to death more often in the future – and apples from Lake Constance could become a luxury item.
Daniel Willhalm bends down between the green leaves and picks up a hand-sized ball. “The kind is called Gandalf,” he says. It is a particularly sweet cantaloupe. The fruits are ripe in about two weeks. Willhalm then sells the freshly harvested melon with the orange-colored, juicy flesh at weekly markets in the Allgäu.
“Many were skeptical at first: ‘They can’t taste good here, far too little warmth, far too little sun, they actually come from Spain, Turkey, somehow from the hot countries.’ But we convinced,” he says. The fruits grow here above Lindau on Lake Constance in six rows under an open foil tunnel. Next door numerous watermelons grow outdoors. They still have to mature a little longer.
For a number of years, Willhalm has not only experienced that, in addition to pears, cherries and strawberries, peaches, apricots and recently melons also cope well with the climatic conditions on Lake Constance. Other apple varieties are now growing there than before. Like “Fuji”. A crisp, late variety. The master gardener also mentions “Braeburn” and says: “When we started growing fruit in Lindau, that would not have been possible.” In the future you have to be a little willing to experiment. He is already worried about climate change.
The soil in the apple orchards is hard, dry and rutted. Further down, says Willhalm, it’s still damp. Nevertheless, he is thinking about expanding his irrigation system. Drop by drop then reaches the roots of the young apple trees via hoses.
A lot of fruit is traditionally grown in the Lindau region.
Tens of thousands of euros for hail protection
He just stretched tens of thousands of euros in hail nets over the trees to protect them. Willhalm says: “It’s the case that we used to have very little hail in Lindau. Of course it happened again and again. The strength of the storms is simply increasing.” For some time now, he has also been observing longer, much more constant weather phases than before.
Like this year. First it rained for weeks, now it has been sunny and warm for weeks, with hardly any rain. In the future, Willhalm and his colleagues will face completely different problems, all over Germany.
And that sounds paradoxical at first: the earth is warming up more and more and the number of frosty days is decreasing overall, while the blossoms of the apple and pear trees freeze to death in spring. The consequences are crop failures and damage to the fruit. Of course they can still be eaten, but they are not allowed to be sold. In fact, that’s already a reality.
In recent years, flowering has always been around two weeks earlier than the 30-year average. The following frost days in 2017, for example, led to losses. Farmer Willhalm says: “That was the first year in which we had that massively in our region. We still had a 35 percent harvest on the farm.”
Extensive data analysis
And the development will increase as the climate crisis progresses. Every ten years, flowering starts around five days earlier. This is shown by data from the German Weather Service (DWD) and the Bavarian State Office for the Environment (LfU), which data journalists from the BR looked at more closely and processed interactively.
While the apple blossom in Bavaria in the 1990s was still early/mid-May (May 4-9), today the trees begin to sprout buds as early as the end of April (April 24-29). In the south and east of Bavaria, this development will be stronger in the future than in Franconia and the Upper Palatinate.
Apple cultivation is fundamentally at risk
Nationwide, the risk of frost in the early flowering period in the northern growing areas will continue to increase, according to research from the Humboldt University in Berlin, for example. According to some models, the climatic changes in the south could even endanger the fruit-growing areas around Lake Constance. And in the middle of the century. Germany in 2050 without apples from Lake Constance?
Climate researcher Carl-Friedrich Schleußner examined this in more detail with a colleague from the HU Berlin. Farmers have approached the scientists themselves. You’ve wondered if there could be more frost damage despite warmer winters and climate change. “And we can answer that question in the affirmative,” says Schleußner.
Higher risk of crop failure
The following applies: The fewer climate protection measures, the stronger the warming and the earlier spring and the earlier the blossom, the higher the risk of crop failures: “Because frost doesn’t mean that we have to have minus ten degrees to avoid frost damage to fruit trees or blossoms to get, but only below zero.” And the scientist sees another problem.
In order for apple trees, for example, to be able to sprout their blossoms at all, they need periods of rest and cold. Farmers speak of cold shock. The vegetation has to shut down in order to be able to start again in spring. “And the problem is that this cold phase is no longer sufficient to put the plant in this state at all,” says climate researcher Schleußner.
Not cold enough for apple trees anymore
While in the north of the country, for example in cultivation areas such as the Altes Land and on the Lower Rhine between Cologne and Kleve, the risks of frost damage will continue to increase in the future, the surveys, especially in the direction of Lake Constance, could even indicate “that maybe in itself Apple growing is in danger because the winters aren’t cold enough anymore.”
Schleußner speaks of “increasingly Mediterranean climate conditions” that will be seen in parts of southern Germany. He says: “We don’t have any apple orchards in southern Italy – there’s a reason for that.”
A melon plant with fruit – the fruit grows here above Lindau on Lake Constance in six rows under an open foil tunnel.
Insurance against frost damage
Fruit grower Willhalm is therefore experimenting more and more with the unknown. His melons, for example, seem to be thriving. And when it comes to frost, you don’t have many options, he says. In the fight against cold nights, the farmers on Lake Constance, for example, light small fires in the plantations. One or two degrees more from the warm smoke sometimes damage the trees.
In other places that are closer to rivers, farmers sprinkle their systems with water, for example on the Lower Rhine and in the Old Country – the frozen water then wraps around the flowers like a protective shield. However, frost protection irrigation is expensive and requires an enormous amount of water. Willhalm has now insured his business in order to at least be financially secure in the event of a frost.