On May 18, the Guo Ke team of Institute of Botany, Chinese Academy of Sciences found a fir tree with a height of 83.2 meters in the mountainous area along the Chayu River in Chayu County, Tibet, setting a new record for the tallest tree in China. This article was written before this discovery, and recorded the discovery process of Sindabu, the tallest tree in Chinese mainland, and its story with human beings.
In the process of searching for the tallest tree, they witnessed the transformation of local people from hunters to forest protectors, and also realized that there are many places in nature that are difficult for human beings to reach.
Looking for the "tree king" Sindabu and making it public is to show the public the ecosystem it represents, the real virgin forest and its value to human beings.
This article first appeared in Southern People Weekly.
Editor/Zhou Jianping rwzkjpz@ 163.com
Menba people in Green Village have always known that there are several towering trees in the mountains. Walking all the way down the mountain from the village and passing the most remote village households is a virgin forest. The life of the green village once depended on it to a great extent. People slash and burn in the forest, cut down trees to build houses, and here they need firewood to cook and keep warm. For men who often walk in the forest, giant trees, like rivers and peaks, become a calibrator for identifying directions. Women generally don't go into the mountains, and occasionally when they use baskets to help transport firewood, they will sigh, "This tree is really big."
The tallest tree is a Bhutan pine, almost twice as tall as the surrounding trees, and it takes four adults to hold it. There is a Bhutan pine tree behind it, almost as tall and as strong as it. Fell in the 1950 earthquake with magnitude 8.6. Fortunately, it didn't fall down, but it also broke the trunk in the earthquake and grew the top again next to the broken branches.
The forest where it grows is about 1700 meters above sea level. Warm and humid air currents in the Indian Ocean bring abundant precipitation, and Medog's heavy valley evaporates perennial fog, forming a typical mountain rainforest.
It has countless neighbors. The largest number of shrubs is mainly acanthaceae, which grows as tall as people. There are flowers of Malan in Compositae under the bush, which will bloom like stars around 10 and shine under the fog. Some broad-leaved trees, such as Schima superba and Cyclobalanopsis glauca, surround it, and ferns of all sizes fill the gaps with soil. The oldest species is Echinococcus from the dinosaur era. It also comes with many orchids, azaleas, chrysanthemums, radishes and Parthenocissus tricuspidata.
In the hundreds of years of its growth, few people know its existence except the Memba people who live here. It is hidden in the rain forest of the green village, the rain forest is hidden in the endless forest of Medog, and the whole Medog is hidden among the snow-capped mountains on the plateau, like a "hidden lotus".
In 20 13, Li Cheng, the head of Xizijiang Ecological Conservation Center, broke into the "Lotus Mystery" and found the tree. He put forward the viewpoint that the tallest tree in China is Bhutan pine, and made important preliminary work. Nine years later, with the joint efforts of Shanshui Nature Conservation Center, Xizijiang Ecological Protection Center, Professor Guo Qinghua from Peking University Institute of Remote Sensing and Geographic Information System, and the Forestry and Grass Bureau of Motuo County, Linzhi City, Xizang Autonomous Region, this tree was identified as the tallest tree in Chinese mainland at that time on May 8, with a height of 76.8 meters.
Li Cheng named it "Sindabu", which means "Tree God" in Menba language.
Potential tree king
It is not easy to measure the height of a big tree. The most traditional way is climbing survey. In 202 1 year, the 72-meter-high Taiwania flousiana in Gaoligong Mountain, Yunnan Province was measured in this way. But climbing such a height requires professional protection. The closer you get to the top of the tree, the greater the danger.
Since 20 13 discovered Sindabu, Li Cheng has been thinking about how to measure its specific height. 20 16 he prepared a simple laser rangefinder, and the measured figure was 79.8 meters. 20 18 years retest score 8 1 m. He felt that the data was inaccurate and wanted to measure it with a drone, but the drone was out of control and hung on the tree next to it.
202 1, Li Cheng made up his mind to give a conclusion to Xindabu, and contacted Guo Qinghua through Lv Zhi, a professor at Peking University. Coincidentally, Guo Qinghua of Peking University also wants to find the tallest tree, and is leading a team to make a map of forest canopy height distribution in China. They collected the lidar data of tens of thousands of ground and unmanned aerial vehicles in China, and combined with the spaceborne lidar data, they found that the canopy height of the forest in southeastern Tibet is one of the highest areas in China, with an average height of 25 to 30 meters or even higher, much higher than the mainland, and there may be the tallest tree in China.
Li Cheng shared the location information of Bhutan pine forest, and Ren Gan, a postdoctoral fellow of Guo Qinghua's research group, brought instruments, and an investigation team was built. From April 28, 2022, they officially began to measure in Medog. According to the observation in Medog, Sung Jae Lee for many years, the investigation team first scanned several distribution areas of Bhutan pine in Gelin Village with unmanned aerial vehicles, and found that there were 1 1 tree with potential height higher than 70 meters. After that, they measured each tree separately with backpack lidar.
Ren Gan has been engaged in remote sensing research and analyzed a wide range of satellite image data, but it is the first time to enter the virgin forest. Before leaving, she bought a jacket and cross-country shoes as hiking equipment. The first tree they measured on the spot was located on the edge of a cliff, which was the longest and the most difficult to walk. During the first measurement, they walked back and forth for 8 hours, but because of the rain, the lidar could not be used normally. The second time I went, I had experience and went back and forth for six hours. This road needs to pass through a large area of dense vegetation, muddy and slippery virgin forest, and then climb a steep hillside. Many times, Ren Gan has to climb the rock with both hands to move forward.
More disturbing than mud, fallen trees and rocks are a large number of mountain leeches, which live among plant leaves and quickly adsorb to clothes, shoes and socks when people pass by, feeding on blood, especially in rainy days. By the time Ren Gan noticed, there were already many leeches rolling around him, one of which was a finger long. She was scared, but no one in the company responded. She can only force herself to calm down and pick out the leeches one by one through her gloves.
When he was bitten by a leech for the first time, Ren Gan heard that salt could be dealt with, so he raised his hand to look for salt everywhere. When he found it, the leech sucked enough blood and fell off automatically. After being bitten several times, she has been keenly aware of the existence of leeches. Whenever any part of her body feels tingling or cold, she can reach out and pick one.
After investigating all the trees in 1 1, it was confirmed that 8 trees were over 70 meters high and 2 trees were over 76 meters high. One is the tree on the edge of the cliff, and the other is Sindabu in the forest, between which the king will be born. Ren Gan and other team members used drones combined with backpack lidar to repeatedly measure the two trees, and used drones to hang fishing lines at the top of the trees for verification. Visually, the tree on the edge of the cliff is taller because its dense roots are exposed, but the roots can't be counted as the height of the tree, and the measurement should be based on the dividing line between branches and roots. On May 8, the results were officially released, and Sindabu became the "tree king" with the advantage of dozens of centimeters.
"Many people urge us to get the results as soon as possible, but we hope to get more accurate data." Ren Gan said, "Lidar is the most accurate measurement method at present, but in order to make the result more intuitive, we measured the object with fishing line and found that the error of lidar is within 10 cm."
During the ten days of intensive research, Ren Gan and the members of the research team were very busy, going out in the field during the day and analyzing the data with the team in Beijing at night. A few days ago, they gathered at 8 o'clock in the morning. Later, they found that there was fog in the mountains in the morning, which would affect the work of lidar, and they waited until the fog cleared.
The natural environment of Green Village is beautiful, with lush forests and snow-capped mountains far away, but Ren Gan seldom lets go to appreciate it. She is used to controlling risks, and the first two things in her mind are to complete the measurement goal and not to get hurt in the forest. Every day, her happiest thing is that when she walks out of the forest in the evening, there is a stream crossing her path, and the sunset makes the river glow with golden light. Ren Gan crossed the stream, looked back and finally took out his mobile phone and took a photo.
Green forest
In the case of tight heartstrings, Ren Gan still felt the healing of the forest. There is a sky between the branches of the new cloth, surrounded by vines and moss on trees. When Ren Gan looked up, she could see that she felt the vitality of the tropical rain forest. There is another place in the forest where three tall Bhutanese pine trees grow. There are not many other trees around, only some low herbs. Ren Gan feels that there is a magical atmosphere here, and he feels very comfortable every time he passes by. When she told Third Sister, a villager in green, Third Sister told her: There is a saying in Menba that there are three brothers at home, and others dare not bully them. "These three trees are like three brothers in a family."
Most of the men in the village undertake the work of rangers and patrol the mountains in turn once a month. Sanjay's Chinese is one of the best, and he became the guide of the investigation team. Every time he entered the mountain, Sanjie took a Tibetan knife and a bag of salt and cut a path through the dense ferns with a knife. Ren Gan was worried at first whether cutting down plants would cause damage to the forest, but Sanjay promised not to. "In a few days, if no one leaves, it will grow back."
Sanjay will take the initiative to help with the back when the measuring team leader carries the instrument for a long time. He is used to walking in the forest with heavy loads, and he can't breathe for hours. Before Medog Highway, villagers in green clothes walked around and bought salt and clear oil. They had to walk for three days and send them to a town to buy them. When they go, they bring their own cane crutches, yak ropes and wild peppers.
The forest is in a hurry, and Sanjay just leads the way in front, ignoring chatting. When working in the investigation team, Sanjay was idle, cutting some wild fruits for everyone from time to time, or chanting to a certain plant, such as "This is a palm tree, making a mattress, and the core of the tree can be eaten."
In mid-May, Sanjay fell down while riding a motorcycle, and the work of tour guide was entrusted to his cousin Middle East. The Middle East is also familiar with forests. Earlier, life in green villages was inseparable from forests. People of the older generation think that the forest is where immortals live and immortals can meet their needs.
The Middle East is 49 years old. He remembers that before building a house and burning firewood, he took wood from the forest and cut down many trees taller than the new cloth. When planting corn fields, more trees were cut down. Every year in the third month of the lunar calendar, men go up the mountain to cut down trees and open up wasteland. If the fallen trees can't be brought back, burn them on the spot and plant corn. People outside bring wine to say hello, or they can take wood from the forest at will.
"Some places in Medog have experienced slash and burn,' shaving their heads' and cutting down every tree." Li Cheng has seen the old photos of Medog in the 1980s. There are many bare mountains around the county seat. Due to good growth conditions, secondary forests have re-grown in many places.
More than ten years ago, Medog began to ban the felling of trees. The villagers had to buy wood from bomi county, 700 yuan per cubic meter. With the improvement of living conditions, coal and electricity have gradually replaced firewood. With the financial support of the government, every household has built new houses, and the demand for wood has decreased. The Middle East has not bought wood for five or six years.
The villagers' economic sources are gradually getting rid of their dependence on forests. Huang Jiabin, who worked as a secretary in the village four years ago, took the villagers to develop the under-forest economy, planted precious medicinal materials such as Ganoderma lucidum and Hericium erinaceus in the village, built tea gardens and fish ponds, and used idle houses to open homestays to stabilize the income of the villagers. In addition, villagers can get a forest protection subsidy every year.
Li Cheng is happy with this change. "All the tour guides I have worked with have become friends who have known each other for more than ten years. I watched them change from hunters to forest protectors. "
Unfortunately, the forest that was originally cut down, even if it grows into a secondary forest now, is far from being compared with the original forest in biomass and biodiversity. Most of Medog's giant trees, including Sindabu, are in the remaining virgin forest.
Growth is survival.
After finding Sindabu, the next important task is to study why it can grow so tall.
Li Cheng believes that the existence of giant trees such as Xindabu can reflect the process of primitive forest succession. From the edge of the green village to the forest, the forest within an hour's walk is almost entirely Bhutanese pine. The deeper you go, the higher the Bhutanese pine is and the thicker the tree is. This is a typical secondary forest of Bhutan pine. "First, the conditions here are very suitable for Bhutan pine; Second, there is the same kind of competition within this community. In order to survive, individuals of the same species must grow taller at the fastest speed so as not to be excluded by the same species. " This is the early stage of forest succession.
"Going deeper, you can see some shady evergreen broad-leaved forest trees, such as Schima superba, Cyclobalanopsis glabra, Schima superba and so on. , will invade Bhutan pine forest, develop at the bottom of Bhutan pine forest, absorb a lot of nutrients and occupy a lot of living space. Bhutan pine is a positive tree species, but it can't compete with them. Only by constantly growing and reaching a higher level can the evergreen broad-leaved forest be perfected and the dense evergreen broad-leaved forest canopy not cover it as a whole.
"Those trees that can't grow will slowly decline, so you can see so many fallen trees in the forest, some of them are earthquakes, and some are natural deaths. In the end, only those Bhutanese pines that can grow very tall survived, and their height in this forest exceeded the average crown height of mountain rainforests. "
What specific factors contributed to the growth of Sindabu? Li Cheng's first thought was the fog of Medog. By consulting the existing research, he found that there are more foggy days in places where tall trees are distributed all over the world. For example, the northwest coast of California, where giant sequoias grow. "Fog, also called parallel precipitation. Trees transport water upward from their roots to resist the gravity of the earth. The higher the tree, the greater the restriction of gravity on its growth, and the leaves absorb dense fog water, which can reduce the amount of water transported upward by the roots through the trunk. "
The mechanism of many factors acting on tree height is complicated. Guo Qinghua once studied the relationship between water content and tree height, and found that tall trees usually grow in water-rich areas, but too much water will inhibit the growth of trees, which makes the growth of giant trees still a mystery that cannot be completely explained. Guo Qinghua intends to further find out the age of Sindabu and its surrounding community structure, so as to study the influence of local climate, competition among communities and natural interference on its growth.
His interest in giant trees began with redwoods in California. While studying for a doctorate in California and teaching at the University of California, Guo Qinghua often went hiking in Sequoia National Park. After 20 12 returned to China, he always wanted to find the tallest tree in China. "The best way is to scan the crown of the national forest with lidar, so that we can know where there are potential big trees." To this end, he started with the research and development of lidar software and hardware, and drew the national forest canopy height distribution map in early 2022.
"A very important advantage of lidar is that it can emit hundreds of thousands of points per second for CT scanning of the earth. This is called a laser pulse, which can scan the whole forest, including the underground. " Guo Qinghua explained.
At present, Ren Gan is still collecting data with lidar at the scene. In addition to studying Sindabu, she will also drive a drone across the Yarlung Zangbo River to the more remote virgin forest in Medog to explore whether there are taller trees there. Li Cheng and Guo Qing Huadu believe that it is entirely possible to be in Medog, where water resources are abundant and isolated from typhoons and lightning, but it is not easy for human beings to reach.
"The forest can hold everything."
20 13 Up to now, every time I go to Medog, I can surprise Li Cheng. He is mainly engaged in wildlife monitoring and biodiversity protection in Medog. Once or twice a year, he set up an infrared camera in the forest, and the next time he went to collect data, he traveled to every town and most villages in Medog.
In this humid area of the northern hemisphere, where there are almost all vegetation types, infrared cameras can always record new species. In 20 15, they discovered a new species of monkeys-white-cheeked macaque, and there are still species that have not been recorded. "Many scientific research teams in China are constantly discovering new recorded species here, which proves that it has great potential and is an Eden worthy of protection."
Li Cheng was originally engaged in the IT industry, but he changed careers because he loved the forest. He likes hiking in the virgin forest of Medog, and he dares to spend the night in the forest with Tibetan knives and necessities of outdoor life. He has seen bears, jackals, clouded leopards and other wild animals in the forest, but he is not worried. "This place is rich in wildlife food, there is no need to risk attacking people. For example, when I meet a bear, the first thing I do is to pick up the camera quickly. As long as I don't irritate it and scare it, basically after taking a few photos, it will go away. If the bear really wants to attack you, too much equipment will increase the load and may not help you. "
Compared with wild animals, he pays more attention to walking carefully to avoid falling, falling into cliffs or being washed away by water. Shuttle through the rain forest, meet beautiful birds, smell all kinds of flowers, see strange plants, and look for different flavors of wild fruits ... Li Cheng feels that the friendliness of the forest is far greater than unfriendly.
"The forest is a system that can accommodate everything. You can only touch a certain part of the system from the existing knowledge, but by walking, observing and recording it, you will gradually discover its hidden parts, and I will know which plant parts can be eaten directly and will never die of thirst in the mountains. I need not be afraid of the forest. When I walked in, I was very confident. " Li Cheng feels more and more that forests are built on rules. As long as he has mastered the rules, he has mastered the password of the forest passage.
Li Cheng feels that the process of understanding the forest is also a process of constantly breaking through from the original inner world. In the meantime, you will also experience lessons, such as being stabbed by bristles on hemp leaves and eating poisonous wild fruits. Li Cheng believes that these properties of plants are for their own survival and are not malicious. Forests are tolerant. "Usually few plants can kill people with a little taste. This will teach you a lesson, but it won't kill you. "
Looking for Sindabu and making it public is to show the public the ecosystem and the real virgin forest it represents. Li Cheng believes that people naturally love forests. "People have biological properties and will depend on what nature provides. Whether from personal feelings or from the sense of rising to human beings, forests have various levels of value to people. "