Experts diagnose ancient trees and propose countermeasures.
Trees are like people, in their long "tree life", it is inevitable to experience "three diseases and six pains", from time to time to encounter typhoons, heavy rain, floods and other natural disasters, especially for ancient trees more than a hundred years. People who are sick need treatment, and tree diseases also need to find a tree doctor to "prescribe the right medicine".
On January 12 this year, Guangzhou Nansha District held a letter of appointment ceremony for the "Tree Doctor" expert team, which was the first "Tree Doctor" expert team established in Guangzhou, with a total of 9 experts joining to "take the pulse" of the trees on the ground. The reporter learned that these 9 experts specialize in tree cultivation, soil, pests and other related fields, and over the years, they have left their figures in Guangzhou's Baiyun Mountain, Panyu, Zengcheng, Conghua and even Zhaoqing, Huizhou, Shaoguan, Qingyuan and other places outside the city.
How does the "Tree Doctor" team diagnose and treat local trees? What are the unique features of their diagnostic and therapeutic techniques? Recently, the reporter followed the expert team of "tree doctors" all the way to Nansha to treat trees, during which experts showed their unique medical skills and medical methods in the field of tree treatment.
A century-old banyan tree: first lead its roots and then cure its disease
In a green belt of a main road not far from the Nansha District Government, a 154-year-old ficus tree quietly unfolds its emerald "canopy", and the earliest main root of the banyan tree is intermingled in the middle of the later whisker roots, the branches are scattered, the branches are rooted again, and many roots hang straight to the ground and stick into the soil; and some root systems are slowly hanging down along the tubes that were placed not long ago.
On the day of the interview, the reporter followed Professor Chen Hongyue of the College of Forestry and Landscape Architecture of South China Agricultural University, Dr. Shan Jiang and Yuan Zhonggui, chief economist of the Nansha District Housing and Urban-Rural Development Bureau (Landscaping Bureau), to the old banyan tree. Chen Hongyue is an expert in tree cultivation and ancient tree protection, and Shan Zhaojiang specializes in the prevention and control of tree pests and diseases, and they are all members of the "Tree Doctor" team.
"Banyan trees are the most common species of ancient trees in Lingnan." Chen Hongyue told reporters, "The overall growth of this banyan tree is good, the leaves and canopy are relatively luxuriant, in order to prevent problems before they occur, we still found some problems after careful diagnosis, and proposed countermeasures." ”
Chen Hongyue introduced that the treatment of this banyan tree mainly starts from three aspects. The first is to dismantle the hardened part near the main green space of the banyan tree after consultation with the local village committee, otherwise it will restrict the development of the banyan root system. The green area near this ancient tree is very large, enough for the overall growth of the root system of the banyan tree, after the brick is removed, it is also necessary to cultivate soil and fertilize, "We will use some fertilizers specially used to treat ancient trees, mainly with an appropriate amount of slow-acting organic fertilizer, the ancient trees are older and the same as people, the body will be relatively weak, can not use the medicine of the big tonic, but slowly strengthen its physique." In terms of soil cultivation, we will also use more loose, well-breathable humus soil and other substrates to promote the root growth of future banyan trees. ”
The second is to strengthen the overall support of the banyan tree. Chen Hongyue said that at present, the tree body is tilted, the center of gravity has been shifted, once the typhoon blows, it is easy to appear the overall lodging of the tree, so it is necessary to support the banyan tree. As early as five or six years ago, the relevant departments in Nansha District had already used steel pipes to support this banyan tree to avoid lodging. This time, the "Tree Doctor" team pays more attention to helping this banyan tree to lead the roots, once the root system of the banyan tree grows on the ground, it will grow thicker and thicker, becoming a pillar of nature, "We are preparing to use bamboo to do the work of root introduction, break the middle of the bamboo tube, fill in organic fertilizer and soil, and let the root system grow smoothly from the branches to the soil." When these root systems grow and thick, the steel pipes can be removed, and the trees as a whole will be more natural and beautiful. ”
Experts inspect the soil of ancient trees.
The third is to prune the overlapping and intertwined branches of the banyan tree, Chen Hongyue said: "The banyan tree has its natural growth potential, and what we have to do is to try to go with the trend, so that the tree can grow stronger." ”
The monolithic river focused its attention on the decaying branches of a banyan tree. He said: "This section of the branch is mainly caused by wood rot bacteria, we will think after the diagnosis, it is not appropriate to deal with it now, because the branch is still connected to another section of the banyan tree, very thick side branches, once the 'scraping bone to cure poison', the side branches are likely to break in strong winds." At present, there are many air roots in the side branches, and the top priority is to set up a support for the side branches, and then quickly introduce the roots for the side branches, and the roots grow up to become new trunks before dealing with the corrupt branches. ”
Shan Hujiang said: "We have carefully investigated, there are only some banyan tube thrips that harm the young leaves of banyan trees, but it is not a big problem, it is not as long as there are insects to kill, but to pay attention to the overall growth of the tree, can not do a 'general anesthesia surgery' for a 'pimple'." ”
Century-old lychee tree: slowly replenish the body Do not attack with fierce medicine
After leaving the ancient banyan tree, the "Tree Doctor" team rushed to see the second "patient" of the day, a century-old lychee tree. More than 120 years ago, villagers in Shajiao Village, Lannuo Town, planted 17 concubine smile lychee trees in the Hengli River town, and today, most of these 17 century-old lychee trees are still leafy and lush. But in the middle of this row of lychee forests, there is one tree that grows weaker than other lychee trees, although the branches still have green leaves, but there are some dead branches, and the fruit-bearing lychees are much less than other trees.
Century-old lychee forest
Knowing that the "Tree Doctor" team was coming, Lin Zhishan, the village secretary of Shajiao Village, rushed to meet him. Lin Zhishan told reporters: "The fruits of these 17 lychee trees are very sweet, and there is no slag. In a good year, 17 trees can produce almost 2,000 catties of lychees. Because it was planted by ancestors and has good economic benefits, everyone likes this lychee forest on the edge of the village very much, so we found that one of the lychee trees was sick, and we were very anxious. ”
Chen Hongyue and Shan Hujiang immediately investigated the diseased lychee tree. They learned that this row of lychee trees grew on the river embankment, and occasional flooding occurred during the "dragon boat water" season, and the soil condition near the diseased tree was not too good, and the compaction was relatively strong, although the villagers had removed the hardened stones around the embankment, and applied organic fertilizers such as peanut bran to improve the soil, but the tree's growth was still not very good; Shan Jiang said that the trunk of the tree was smooth and tidy, and no signs of disease and insect harm were found.
Therefore, Chen Hongyue suggested that the treatment of trees should start from two aspects, one is to further improve the soil, use special fertilizers for the treatment of ancient trees, and at the same time loosen the soil, increase the permeability of the soil, improve the compaction of the soil, and even replace some softer soil, which is conducive to its root growth; on the other hand, it is to prune off the withered branches of the tree to ensure the nutrition of the tree. Shan Shujiang also suggested that this year is not suitable for this lychee tree to hang fruit, you can manually cut off the fruit, "hanging fruit is very depleting of lychee tree nutrients, we must minimize the reproductive growth of this old tree, promote its nutrient growth, as soon as possible to restore to a healthy level, remove the fruit can let it get the opportunity to recuperate." ”
"At present, we are mainly using 'Traditional Chinese Medicine' to condition the body of this tree, and the diseased tree will not grow again so quickly." For ancient trees that are more than a hundred years old, it is especially taboo to give 'strong medicine', such as applying more compound fertilizer and inorganic fertilizer, which is especially cautious. Chen Hongyue said.
Lin Zhishan told reporters that at present, the maintenance and picking of these 17 century-old lychee trees is contracted by a villager in this village, "because only the villagers in this village have the most affection for these lychee trees, and they will not fertilize and give strong medicine for economic benefits, in order to protect these trees, we basically only apply organic fertilizer." ”
In addition, the relevant person in charge of the greening of Lannuo Town told reporters that in the future, they intend to create a lychee park for these 17 ancient lychee trees to further protect the ancient lychee trees.
"Shoot CT" to detect the hole and "hang the needle" to supplement nutrition
In addition to treating trees in Nansha, "tree doctors" such as Chen Hongyue and Shan Shujiang have also treated many ancient trees in Guangzhou over the years. Shan Jiang said that because of the age of ancient trees, the growth trend becomes weaker, and the trunk or root often rots, which is mainly caused by basidiomycetes or ascomycetes, root rot, "wood rot, root rot is the most common infectious disease in ancient trees." ”
According to the monomer River, termites are the main pests that threaten ancient trees, and others like wood beetle moths, camphor nest borers, camphor silkworm moths, etc. that harm camphor trees are also more serious; the more serious harm to kapok, yellow kudzu banyan trees, human face, white orchid, nanyang jacaranda, etc. is mulberry parasitism, mistletoe parasitism, which will lead to weak tree growth, top branches and death, etc., once the typhoon is blown, it is easy to break branches; as for banyan trees, it is easier to be harmed by pests such as vermilion spotted moths and banyan tube thrips, "Wood beetle moths mainly eat bark, which can easily cause the death of trees." Like the vermilion spotted moth, it has occurred more seriously in the Pearl River Delta region on fine-leaved figs and weeping ficus, and even began to harm alpine figs. This moth can eat the leaves of a banyan tree in two or three days, and there is no effective prevention and control method, and spraying chemicals is still the main prevention and control measure. ”
Shan Shujiang frankly said that some tree diseases will also make the "tree doctor" lack of skills: "In the past two years, the most harmful is pine wood nematode disease, which can be said to be the 'cancer' of pine trees, and once the pine tree is infected, it can only be cut down as soon as possible to avoid endangering other health pine trees." ”
Chen Hongyue and Shan Shujiang introduced that there were originally many traditional methods for diagnosing and treating tree diseases. With the progress of the times, more and more new technologies have been applied to the diagnosis and treatment of ancient trees.
In the diagnosis of tree disease, Chen Hongyue introduced that there are currently some advanced instruments and equipment for ancient trees and famous trees to do "CT", such as the use of stress wave data to determine the internal defects of trees without damage detector, "this machine can specifically detect whether there is decay and hole in the trunk." For the root system of ancient trees, there are also machines like trolleys that use radar detection technology to detect the distribution of underground roots, and their accuracy can detect roots as small as the thickness of a pencil. If you find that some trees have difficult diseases, you can't find out the cause from the outside, and you can also know the situation inside by scanning the machine. ”
Whether the trees grow well or not, the soil is very critical. Chen Hongyue told reporters that there are 9 experts who specialize in soil research, "We will not only measure the pH value and element composition of the soil, but also collect ring knife soil on the spot to understand the physical properties of the soil, such as the ability of soil seepage, permeability, porosity, and whether the soil is partial sandy soil, loam, clay, etc." ”
Chen Hongyue conducted a "health examination" on the ancient tree.
At the same time, some new materials have emerged for the treatment of trees. Trees because of pests and diseases or other reasons often appear tree holes, which will seriously affect its growth and stability, single Jiang told reporters, in order to repair tree holes, in the past will be directly with bricks and cement to fill, but cement, bricks do not have flexibility, once the typhoon trunk is easy to break in the place of repair; now many companies develop and produce shrinkage and wood is roughly equal to the charcoal and polyurethane or urealdehyde resin foaming agent and other new fillers, which makes the flexibility of trees enhanced, more conducive to responding to natural disasters.
In addition, although "hanging needles" for trees are now a common treatment, they are also constantly innovating in injections. Single body Jiang introduced, the hanging needle is mainly hit in the formation layer of the bark, the nutrient solution in the hanging needle is usually rich in nitrogen, phosphorus, potassium and other nutrients necessary for plant growth, "trees are usually absorbed through the root system, and then through the catheter to transport nutrients up, the main need for 'hanging needles' is those root systems have problems, can not absorb enough nutrients of the trees, 'hanging needles' is not a long-term solution, the key is to solve the root problem, so some scientific research units and enterprises are also developing ancient tree special fertilizer to promote the absorption of ancient tree nutrients." ”
One tree, one policy, joint diagnosis: more than 80 diseased trees have been prescribed
Yuan Zhonggui introduced to reporters that in order to protect trees, especially ancient trees, the relevant staff of Nansha District will take the lead in finding out some trees with growth problems, and then contact the "tree doctor" team for joint diagnosis. In addition to Chen Hongyue and ShanZhujiang, the other 7 are Professor Huang Yongfang, Professor Zeng Shucai, Associate Professor Li Yizhen, Associate Professor Weng Shufei of the College of Forestry and Landscape Architecture of South China Agricultural University, Zhu Chun, editor-in-chief of Guangdong Garden, Professor Huang Huazhi of the School of Eco-environmental Technology of Guangdong Light Industry Vocational and Technical College, and Professor Huang Songyi of Zhongkai Agricultural Engineering College, who are mainly engaged in landscape architecture design, construction management, garden trees and soil science 2. Research directions such as diseases and insect pests, development and application of garden plants, and rejuvenation and safety management of large trees.
"At present, there are more than 80 trees diagnosed by the 'Tree Doctor' team, not only ancient trees, but also other green tree species, including more than 10 kinds of trees such as banyan trees, lychee trees, phoenix trees, flame trees, camphor trees and beautiful iso-kapok trees." Yuan Zhonggui told reporters, "For the treatment of these trees, experts are one tree and one policy, and each tree proposes a separate treatment and protection measure." ”
Chen Hongyue told reporters: "The protection and treatment measures proposed by experts are very systematic and comprehensive, including not only conventional soil improvement, tree support, nutrient supplementation, pest control, but also take into account the design of landscape gardens, the impact of buildings and wind direction on trees." At the same time, we will also respect folk customs when protecting ancient and famous trees. ”
Shan Hujiang said that for the prevention and control of common tree diseases and insect pests, there are currently relatively mature measures, but nowadays, many trees in urban greening are newly introduced varieties, and these new tree species often bring new diseases and insect pests, which requires "tree doctors" to keep pace with the times and find and solve problems in time.
Chen Hongyue said: "In addition to vigorously protecting ancient trees, we are also carrying out the census and protection of ancient trees' follow-up resources, we define the age of ancient trees to reach more than 100 years, and the follow-up resources of ancient trees refer to old trees that are 80 to 99 years old, they will soon become ancient trees, and we are investigating and registering." ”
Text/Guangzhou Daily all-media reporter Wu Wei
Photo: Guangzhou Daily all-media reporter Wang Weixuan
[ Editor: Lorenjan ]