The tree is greater than the sum of its parts: nature's ways of adapting to the climate crisis

Different species of trees that grow next to each other create a new tree - a cage - that combines the advantages of both species, and is able to cope with the rapid changes in the environment. A new Israeli study inspires cautious optimism

"Genetic variation is important for trees, the method uses its evolutionary tools to overcome the difficulties of the climate." Photo: Benny Shalmon
"Genetic variation is important for trees, the method uses its evolutionary tools to overcome the difficulties of the climate." Photo: Benny Shalmon

Last July, a new record was set in global warming - the average temperature of the earth was the highest measured Since the beginning of measurements in the 19th century. There is no doubt that the climate crisis is already here and that it is not expected to slow down soon. New studies conducted by the Vulcani Institute in collaboration with KKL-Junk and presented In the 52th Annual Conference on Science and the Environment They show how the tree species in Israel change and adapt themselves to the increasing heat and dryness. The studies describe a process that could in the future lead to the formation of new tree species that are more adapted and resistant to the changing climate.

"Many acacia trees in the prairie are dying as a result of a decrease in the frequency of rains and floods," explains Gil Siaki, director of the forest department in the southern region of KKL-Junk. "At the same time, acacia trees were observed that are impressive in size and provide a source of food and shelter for many animals, and are characterized by a massive amount of flowering that almost did not produce pods. After a DNA test, the acacias were identified as cage trees - a combination of the species spiral acacia and the Negev acacia," he says.

Fertilization between species is often known from the animal world - such as the mule which is a combination of a donkey and a horse. But, "Intersexual fertilization in plants is a wider phenomenon than among animals," explains Dr. Rakfat David Schwartz from the Volcani Institute. "We are a hybrid of two parents who mixed their genes and gave birth to an offspring. There are plants that self-fertilize, but with most plants, fertilization is specific to each individual." The study revealed that the enclosures are not fertile, meaning that the "new" trees created cannot continue to fertilize additional trees, similar to the case of the barren mule. The enclosures created are particularly interesting because they are more resistant and prosperous Better than the spiral method and the Negev method. "Genetic variation is important to trees, and the method uses its evolutionary tools to overcome The difficulties of the climate," she explains. In the article published in the magazine "Yer" on the issue of the presence of enclosures between the spiral method and the Negev method in Nahal Shekata, the combination is described that allows the method to take features from two different species and create a more durable enclosure that is adapted to the new conditions created following the climate crisis, primarily the reduction of the amount of available water .

A pine prison in the Yatir forest. Photo: Aviv Eisenband, KKL-Junk

"Genetic examination of material extracted from the needles of the trees showed that these are hybrids between the Jerusalem pine and the Brutia pine." Photo: Aviv Eisenband, KKL-Junk

Not just the method

"In the last decade, individuals were discovered in the KKL-Junk forests, especially in the south of the country, in the old plots that were planted with the Rotia pine species, which showed remarkable resistance to the habitat conditions," says Aviv Eisenband, director of the Forestry and Professional Development Department in the KKL-Junk Forestry Division. "These trees are characterized by their outstanding size and remain green and vital, while the other trees in the plot looked smaller and under severe drought," he explains. Brutia pine, also called Cypriot pine, is a species that originates from Cyprus and Turkey and was brought to the KKL-Junk forests. "A genetic examination of material extracted from the needles of the trees showed that it was a hybrid between the Jerusalem pine and the Brutia pine," explains Eisenband. The test was conducted in a similar way to the research in Shimit, but it is pine In a fertile enclosure, which will continue to further generations of enclosures and in the future may be distinguished as a separate species of pine.

To examine the differences between the caged and the two species from which it was created, the researchers collected pine seeds and found that 5 percent of them were caged. "At the end of the summer the seeds fall to the ground, and at the end of the winter a large part of them germinate, but few of the sprouts survive the dry summer months," explains David Schwartz. After collecting the seeds, the researchers sowed them in five plots, in different parts of the country - from Carmel to Beit Govrin. At the end of winter, 8 percent of the seedlings that germinated were from the seeds of the enclosures, and at the end of the summer, 22 percent of the surviving sprouts were from the enclosures. Furthermore, in the seedlings that were in Beit Govrin, the driest area tested, 42 percent of the sprouts at the end of summer were from the enclosures.

The study of the pines found clear differences in favor of the stock compared to the weak parent in every trait - in the rate of growth, in the physiological traits and in their behavior in response to the lack of water. "Measurements of trunk volume and diameter showed that crossbreeds of Brutia pine with Jerusalem pine show rapid growth compared to Brutia pine in the same plot," says Eisenband. The findings showed that the resulting enclosure had advantages in dealing with drought in Douma To the Jerusalem pine and a higher resistance to harmful aphids, similar to Brutia pine. "The combination of the best traits from both parents explained the advantage of the enclosures in the forest," explains David Schwartz.

Regenerating forests

"The importance of the research is in showing the potential for increasing the 'toolbox' of the planting planners at KKL-Junk, with spontaneous enclosures of Brutia pine and Jerusalem pine. These cages have hybrid vigor (reproductive ability), which gives them both the ability to grow and support vital growth and a better resistance to drought compared to rotia pine trees. These findings are of utmost importance in view of the consequences of the expected climate changes in our region and the continuation of informed and research-based activity in afforestation in Israel," explains Eisenband.

The climate crisis may significantly damage the pine trees and in the acacia trees, and already affects a variety of ecosystems in the world. "Understanding the genetics and physiology of the caged trees is very important from a scientific point of view and may help in the future in examining the possibilities of vegetative propagation (al-sexual reproduction, a.k.a.) or seed multiplication in deliberate hybrids, and this in order to improve the resistance of the trees to the changing climate conditions," explains Siaki. The methods are A key species in the areas where they grow. "Their roots hold the soil, animals feed on them and take shelter under them - and from an ecological point of view the place is in danger," says David Schwartz.

The research on the tree cages sheds light on the adaptation process of nature, even when the changes are rapid and extreme. It gives room for cautious optimism, but also makes clear how important it is to follow and preserve what exists. "There is a situation where the new population has the opportunity to adapt to the new conditions," she concludes.

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