Will we be able to continue enjoying sweet cherries produced in the Blue and White region in a few decades? A new study raises concerns that the warming caused by the global climate crisis will make it very difficult for cherry trees in the Golan Heights to survive.
By Racheli Vox, Angle - a news agency for science and the environment
At this time of early summer, cherry trees are loaded with ripe, juicy fruit. Whether we buy them at the supermarket or visit orchards that offer an experiential self-picking experience, there is no doubt that eating sweet red cherries is one of the fun treats that the month of June brings. However, it may be more difficult to enjoy home-grown cherries in the future. In a new study to be presented at the 2019 Annual Conference on Science and the Environment, to be held at Tel Aviv University on June 19-20, researchers found that the rise in global temperatures caused by the climate crisis will make it very difficult for cherries to survive – and could leave Israel without cherries for many years to come.
The cherry is a deciduous tree, meaning a tree that is characterized by its fall in autumn. The origin of the cherry, like other deciduous trees, is in cold regions, so it has evolved so that it can survive harsh winters. In winter, the trees go into hibernation, which includes, among other things, the loss of leaves. In order for the tree to wake up from hibernation at the end of winter and begin to bloom, it needs to be "convinced" that winter has fully occurred - so this will only happen after the tree has experienced a sufficient amount of cold hours.
Even compared to other deciduous trees, cherries are considered particularly sensitive and need many cooling hours each winter: from 800 to over 1,000 hours, depending on the variety. If the trees do not receive a sufficient amount of cold hours, their annual dormancy and growth cycle can be disrupted. When such a situation occurs, the quality and especially the quantity of the fruits produced by the tree are very low. This also damages the tree over time, and may shorten its lifespan. For this reason, in Israel cherries are grown in areas above 600 meters (mainly in the Golan Heights), where the temperatures are relatively low.
Today, as the climate crisis leads to rising temperatures in Israel, there is concern that the number of cold hours in winter will decrease – which could lead to it no longer being possible to grow cherry trees and other deciduous trees in Israel.
Decrease in cooling hours
The new research, carried out as part of the master's thesis of Miri Kupermintz from the Porter School of Environment and Earth Sciences at Tel Aviv University, under the guidance of Prof. Hadas Saaroni from Tel Aviv University and Dr. Baruch Ziv from the Department of Natural and Life Sciences at the Open University, dealt with the sweet cherry - The common and well-known species of cherries also called Gudgden. The researchers built a forecast for the state of the cherries between 2070-2050. To this end, they relied on blossoming and blossoming data from the cherry orchard in Ramat Magashim, on climate data from a meteorological station near the orchard, and on regional meteorological forecasts (which include, among other things, the expected hourly temperatures).
When the researchers examined the current state of the cherries, they found that over the past 20 years the fruits have enjoyed relatively good conditions: although the average temperature in Israel increased at a rate of about half a degree per decade, this increase was mainly manifested in the summer months, and the cherries received a sufficient amount of cooling hours in the cold winters.
However, the future does not hold good for the Cherries. According to the results of the study, between the years 2070-2050 a 20 percent decrease is expected in the rate of cooling hours that will accumulate in the significant part of the season (November to the end of January) compared to the situation in the last 20 years. As a result, in at least 9 of the 20 years examined, the amount of cooling that is critical to the success of the cherry crops will not accumulate. For comparison, in the last twenty years this happened in only two years.
Although the current study deals only with cherries, other common and beloved fruit trees, such as the apple and the plum, belong to the deciduous group and need cooling hours. Currently, it is not known how these trees will be affected by the expected rise in temperatures in our region, but scientists find it difficult to be optimistic. "Climate change is a very big threat to local agriculture and the country's resilience to climate change," Kopermintz says.
develop new varieties
What can be done to continue growing cherries in Israel in the future? According to Kupermintz, there is no existing means that the farmers in Israel can use to compensate for the significant lack of winter cold that is expected in the next 20 years and is essential for growing fruit trees. This is because today the farmers are already using the existing coping methods in order for the trees to bear fruit in the best quality and quantity in the Israeli climate. These methods include, among other things, spraying preparations that break dormancy, using shade nets in the summer and special pruning measures. "In other countries, where temperature-sensitive crops are grown, a solution (for example for coffee crops) is offered to move the crops to a higher and cooler location," she says. "We in Israel do not have such an option."
According to Cooperminz, the best strategy may be to develop new cherry varieties. "It is necessary to develop varieties that are more resistant to heat and require less winter cold," she says.
Responding to and adapting to the challenges posed by the climate crisis for the cultivation of many food products, including fruits, requires extensive research, risk analysis, and early planning. "Today, there is not enough investment in appropriate research in Israel," says Kupermintz. "There is a great lack of knowledge on this subject, not just in the field of cherries. We need to ensure that studies are conducted that will provide this information, so that we can understand what is expected of us and plan how to deal with the future."
Kupermintz calls on the decision-makers to wake up, before it's too late - and delicious cherries will no longer be a matter of routine in the summer months. "There is little interest among the general public in the consequences of the climate crisis. Perhaps that is why the state and its institutions hardly take a position, plan or set policies in the area of the climate crisis and its consequences," Kopermintz concludes. "The climate changes are already happening and their impact will get worse in the foreseeable future. They are expected to affect the lives of each of us and not for the better. That's why we must give attention and focus to building a policy to handle all aspects of the crisis."
