0 1 Chen Yongzhong, Hunan Forestry Science Research Institute

I. Biological Characteristics of Camellia oleifera Camellia belongs to Camellia of Theaceae, and is an evergreen shrub or small tree. The height of the tree is generally 2 ~ 8m, and the age of the tree can reach over 1000 years. Capsules are spherical, orange, oval, olive and so on. Fruit colors are cyan, red, bluish yellow, red yellow and so on. Camellia oleifera generally enters the high-yield stage after 3 ~ 5 years and 7 ~ 8 years. Camellia oleifera grows to 70 ~ 80 years, and then gradually enters the aging period. Camellia oleifera grows from new shoots, which can be divided into spring shoots, summer shoots, autumn shoots and winter shoots according to different germination seasons. Usually, camellia oleifera is dominated by summer shoots, and winter shoots are common in young trees with vigorous growth. Spring shoots began to germinate in early or middle March and basically ended in early or middle May. Summer shoots generally begin to germinate in the middle and late May and end in late July. The second summer shooting started in mid-July and ended in late August. Autumn shoots usually germinate in early September and end in mid-June1o. Camellia oleifera flowers mostly grow on well-developed spring shoots, and a few well-developed summer shoots can also differentiate into flower buds. Flower bud differentiation begins to form after the new shoots stop growing, and generally takes shape in the middle and late May and late June. Camellia oleifera flowers mostly bloom in late June of 1O, and the peak period is 165438+ 10, and a few varieties of spring flowers bloom in February-April. Camellia oleifera is an insect-borne bisexual flower. After pollination and fertilization, the ovary gradually expanded in mid-March to form young fruits. From the end of March to the end of August, the fruit of Camellia oleifera mainly increased in volume, and the fruit of Camellia oleifera matured in the early or late June of1o. At this time, a large number of upright buds open, forming a strange phenomenon that flowers and fruits appear at the same time, commonly known as "holding a child to conceive."

Second, the high-yield cultivation technology of Camellia oleifera The high-yield cultivation of Camellia oleifera must strictly implement the Seed Law of People's Republic of China (PRC), the High-yield Camellia oleifera Forest, the Measures for the Quality Management of Forest Seeds and the Regulations on the Quality Management of Camellia oleifera Seedlings of the State Forestry Administration. As well as some local standards and regulations, improve the awareness of improved varieties of forest trees, put an end to the use of non-improved seedlings in the construction of camellia oleifera industrial bases, and adhere to the improved, standardized and scientific production of camellia oleifera. 1 Selection of afforestation site Red soil, yellow soil and red-yellow soil should be selected for Camellia oleifera forest land. The soil depth is more than 60cm, the soil is loose, fertile, moist and well drained, the groundwater level is below 1m, and the pH value is 4.5 ~ 6.5. In hilly areas with an altitude of 10o ~ 500m, sunny slopes and semi-sunny slopes should be selected, and the slope direction should be south, east or southeast. The selected forest land should be open and free from cold wind, and the middle and low slopes with a slope below 25 degrees are suitable. 2. Before the planning and construction of Camellia oleifera forest land, a comprehensive planning and design should be made for the forest area. It is necessary to concentrate on contiguous areas as far as possible, divide forest classes and small classes according to topography, landforms and landforms, and plan roads, forest roads and work areas. Where conditions permit, irrigation, water storage and drought-resistant facilities should also be considered. 3. Soil preparation, fertilization and soil preparation should be carried out one year or half a year before afforestation, preferably in the summer and autumn of the first year. Weeds, shrubs and tree shrews must be removed from the forest land in the early stage of soil preparation. Manual cleaning, mechanical treatment or chemical herbicide treatment can be used. The land preparation methods include full reclamation, belt reclamation and pit reclamation. According to the requirements of forest site conditions, topography, slope and management mode, as well as capital and labor, we should choose according to local conditions. Apply farm manure 10 ~ 20kg, cake manure 1kg or compound fertilizer 0.3 ~ 0.5kg to each hole, and then backfill the topsoil. The covering soil should be 10 ~ 15 cm higher than the surface, and the pit should be filled to make it look like a steamed bun. 5. Improved varieties and strong seedlings are the basis of high yield and the premise of high yield, high quality and high efficiency. Afforestation seedlings are required to be Camellia oleifera varieties that have passed the joint examination (recognition) by the national and provincial forest variety examination and approval committees, and seedling size has reached Grade I or above. According to "Improved Variety Breeding and Seedling Quality Classification of Camellia oleifera" (LYl730.3—2008), the annual grafting container, Xinwei, has a height of 7cm and a ground diameter of more than 0.20cm, while the biennial grafting container, Xinwei, has a height of 30cm and a ground diameter of more than 0.30cm. One-year-old family Xin Wei's height 15cm, ground diameter above 0.20cm 6. Whether Camellia oleifera can survive after timely planting is closely related to the planting season. According to local climatic conditions, the aboveground parts of seedlings should be planted in rainy season or when growth stops. Afforestation is generally carried out in February and March of 18. 7. Density control The excellent strains of Camellia oleifera have high yield per plant, and only a reasonable number of plants can effectively form the population yield. The planting density should be 2 ~ 2.5m, 2.5~3.5m and 90 ~ 120 plants per mu. Generally, plants per mu 1 1O are suitable for low hills, and the spacing between plants is 2m×3m. Planting density should be selected according to local conditions. 8. Scientific tending management? (1) Young forest management ① Timely replanting and cultivation? If missing or diseased plants are found, strong seedlings of the same age should be replanted, and management should be strengthened to keep the growth of replanted seedlings basically consistent with that of forest seedlings. At the same time, the seedlings planted incorrectly or with bare roots should be righted and ridged in time. (2) Tending time and frequency are generally three years in a row, twice a year, mainly weeding, loosening soil, cultivating soil, cultivating soil and expanding holes. The first time is May-June and the second time is August-September. The newly-built camellia oleifera forest land can be intercropped with crops to replace tending. (4) Fertilization can be applied appropriately in the year of planting. When conditions permit, after the saplings resume growth in June and July, some dilute human excrement and urine can be properly poured, or 25-50g urea or special fertilizer can be applied to each plant. From the second year, every March, the newly sprouted money lasts about half a month, and 50 ~ 100 g of nitrogen fertilizer can be used per plant; 1 11in early October, soil mixed fertilizer or organic fertilizer was applied as overwintering fertilizer, and each plant was 5 ~ 10 kg. With the increase of tree age, the amount of fertilization will increase year by year. ⑤ There are many crops suitable for intercropping and interplanting in young camellia oleifera forest, but the selection should be reasonable. To choose short plants on the ground, sparse branches and leaves, small root disc range in the underground part, poor growth and low fertility; Crops with strong adaptability, acid resistance, barren resistance and drought tolerance, and without the same pests and diseases as camellia oleifera, lianas are not suitable for use. For example, potatoes are spring crops, soybeans and peanuts are summer crops, and rape, peas and broad beans are winter crops. Intercropping crops should be about 60 cm away from Camellia oleifera plants. ⑥ When the length of camellia oleifera is about 1m, the trunk should be shortened at the place where the young trees are 0.5 ~ 0.8m from the ground. When new branches germinate, 4 ~ 5 strong branches with different directions and the upper and lower spacing of 1o ~ 15cm should be selected as the main branches. Young forest pruning and shaping, focusing on light construction, controlling long branches, promoting the growth of main lateral branches and cultivating natural round-headed happy crowns. When the distance between the main branches is too large, the branches with good cultivation prospects should be selected as the secondary branches, and the distance between the main branches and the secondary branches should be kept at 6 o ~ 70 cm, so that the lateral branches can receive sufficient sunshine. The redundant branches and over-dense branches sprouting on the base or trunk of the main branch should germinate early or be cut off in time. ⑦ Control characteristics of anthracnose of camellia oleifera: Anthracnose mainly harms leaves, branches, buds and fruits, and often causes deciduous leaves, dead branches, buds and fruits. At the beginning of the disease, brown spots appeared on the peel, and then expanded into brown circular spots, sometimes several of them combined into irregular shapes, with no obvious edges, and the diseased fruits fell early; Leaf lesions mostly occur at the tip or edge of leaves, which are brown to brown, round, semi-circular or irregular; The diseased spots on the branches are mostly rectangular or prismatic, the affected parts are sunken, the xylem is black, and the edges are wavy or irregular. Canker spots can also be seen on the trunk of big trees when they are grafted to change crowns. Time of onset: It usually occurs in the high temperature and high humidity season from May to August, and the peak of onset occurs in July-August, and a large number of fruits and leaves will fall in the forest from August to September. Control methods: ① Comprehensive control: cooperate with afforestation measures to reduce the source of disease and remove diseased leaves, diseased branches, diseased fruits and historical diseased plants; ② chemical control: spray 1% bordeaux solution (tung sulfate: quicklime: water =1:1:kloc-0/00) regularly in spring and summer seedling stage, and use 50% carbendazim and other systemic fungicide for control in early stage. Characteristics of Camellia oleifera soft rot: Camellia oleifera soft rot, also known as defoliation, mainly occurs on fruits, leaves, buds and branches, causing a large number of fruit drop and dead branches. Brown or yellow-brown water stains appear after leaf infection, and the diseased leaves fall off within 2-3 days; After the bud tip is damaged, it is yellowish brown and dies soon. After the fruit is infected with the disease, there are pale yellow spots like water, and there are small brown spots in the center of the disease spots, which often fall off within 2-3 weeks. Time of onset: the peak period is usually March-June and 10- 12. In southern China, it may happen all year round, leading to seedling death after defoliation. Control methods: ① Comprehensive control: mainly take forest management measures to remove diseased leaves and fruits on trees or on the ground and eliminate overwintering germs; ② Chemical control: 1% bordeaux mixture has better control effect, followed by carbendazim and tobrazine. Characteristics of root rot of Camellia oleifera: Root rot mainly harms annual seedlings of Camellia oleifera. The pathogen first infects the roots and necks of seedlings near the ground. At first, the affected tissues were brown with white hairs on them, and quickly spread upward on the soil surface. The roots of the damaged seedlings rotted, the leaves withered and fell off, and finally died. The onset time: April-May and 9-65438+ 10 are the peak months of onset, and July-August is the death period of severe disease strains. Prevention and control methods: ① comprehensive prevention and control: from the choice of nursery land, pay attention to soil quality and drainage; ② Chemical control: After the disease onset, remove the seriously ill plants and cover them with hydrated lime mixed with soil, or irrigate the roots with 5 o% triadimefon and 5 o% carbendazim. Main pests and their control measures will cause economic losses. Camellia oleifera pests mainly include leaf-eating pests, such as inchworm and tea borer, including thorn moth, moth, scarab, leaf beetle and so on. Branch pests, represented by tea-leaf moth and oil-tea scale insect, include oil-tea borer and scale insect; Dry-eating pests represented by blue-winged longicorn beetles; And seed pests such as tea seed weevil. Prevention and control of pests and diseases of Camellia oleifera: ① Comprehensive prevention and control: strengthening forest management, pruning and removing pests and weak branches, and eliminating overwintering pests; ② Biological control: protecting natural enemies; ③ Chemical control: 2-3 years old leaf-eating pests of LEPIDOPTERA and COLEOPTERA can be controlled with 90% trichlorfon and 50% phoxim EC, sucking pests such as aphids and scale insects can be controlled with 40% dimethoate EC or omethoate EC, and boring pests such as tea borer and tea borer should be controlled with 40% omethoate EC and other chemical pesticides with strong imbibition at the peak of adults, early hatching of eggs or peak of larval migration. (2) Forest management ① There are many kinds of soil improvement and reclamation, such as total reclamation, strip reclamation, cave reclamation and bench reclamation, furrow fertilization and tending. Among them, step reclamation is simple and easy, and the effect of increasing production is remarkable. Stepped reclamation is a kind of terraced field with high outside and low inside, and furrows in the outside, which is formed on the basis of comprehensive deep excavation and cutting down shrubs and weeds. The width of terraced fields depends on the slope. The slope of 15 degree can be made into a terrace with a width of 3-4m, and if it exceeds 15 degree, it can be made into a terrace with a width of 1-2m. Drains, storage tanks and grit chambers should be dug on both sides of the ladder. Reclamation includes winter reclamation and summer reclamation. The depth of winter reclamation is generally 20 ~ 25 cm, and the clods are turned over with the roots facing the sky. The depth of reclamation in summer is generally 1o ~ 15cm, so shallow shovel is needed. Digging once every three years and shallow hoeing once a year. (2) Rational fertilization: apply quick-acting fertilizer in spring at 0.5 ~1.0 kg per plant; In winter, apply 20-30 kilograms of organic fertilizer such as soil mixed fertilizer or farmyard manure, and spray quick-acting fertilizer or foliar fertilizer as appropriate. The fertilization method is to dig a circular or rectangular ditch at the protruding edge of the crown, with the width and depth of 30-40cm, and cover it with soil after fertilization. Fertilization of Camellia oleifera is best to combine mountain cutting in winter and intertillage in summer. In the new year, more nitrogen and phosphorus fertilizers should be applied to promote fruit preservation, oil growth and twig cutting; More phosphorus and potassium fertilizers should be applied in small years to protect fruits and promote flower bud differentiation. (3) In the years with severe drought in water management, especially in the years with poor soil water-holding capacity and in the first 1 and second years after afforestation, 1 ~ 2 artificial droughts should be carried out from June to August, and it is advisable to water them in the morning and evening. (4) The time for scientific pruning is from fruit harvesting to spring shoot germination (165438+ 1 month to February of the following year). Pruning objects are dead branches, diseased branches, long branches and cross branches. Pruning principle is that young trees are lightly pruned and old trees are re-pruned; New year's heavy chopping, young people chop. Methods according to the tree type, cut the lower part first, then cut the middle and upper part; First cut the crown, then cut the outer crown. Do trim evenly, do not overlap up and down, do not crowd left and right, and leave piles too high. The incision should be smooth and slightly inclined, and the incision should be closed with wax or yellow mud. Don't chop branches with machetes, especially big branches, and chop branches with saws to avoid damaging trunk bark and causing diseases and pests.

Third, the comprehensive transformation technology of low-yield camellia oleifera forest (I) Definition of low-yield camellia oleifera forest exists relative to high-yield camellia oleifera forest, and the division standard varies from place to place. Low-yield forest mainly refers to the forest whose production capacity has not been fully exerted or has not been fully exerted. (II) Present situation and significance of low-yield forest transformation At present, the stand area of low-yield camellia oleifera forest in China is very huge, and the proportion of improved varieties in China is less than 10%. The core problems of low-yield forest are mainly the low yield per unit area of large camellia oleifera, the large proportion of secondary forest and the poor production efficiency, that is, the general situation of camellia oleifera "inferior, sparse, dense, old, sick and barren" The main reason is that the management is too extensive, the forest land is barren and serious, and the long-term natural succession leads to mixed varieties and poor quality. The stand is in a wild or semi-wild state, and basically only fruits are picked without input. Through the application of improved varieties of Camellia oleifera and the implementation of projects, the transformation of low-yield forests has achieved good benefits. For example, the rolling implementation of the "2696 Project" aided by the United Nations and the national low-yield forest transformation project has brought Camellia oleifera production to a higher level. Yongxing, Changning and Leiyang counties have transformed 90,000 mu, and the average oil production before the transformation is 1983- 1985. The 4000 mu low-grade forest in Hengdong County increased from 4.2 kg before transformation to 1988 ~ 1989, with an average of 23.2 kg. The annual oil output of the pilot forest of Camellia oleifera clones in Xinshi Camellia oleifera farm in Youxian County reached 40.5 kg/mu in the fourth year after transformation, and now it is basically stable at the level of 30-50 kg. After deducting the investment in that year, the average net income per mu is close to that of 500 yuan. (III) Classification of low-yield forests According to site conditions and yield levels, low-yield forests of Camellia oleifera can be divided into four categories. The first type of forest is a forest with good site conditions, neat forest appearance, high management level and annual oil production of more than 5 kg per mu; The second kind of forest is a forest with good site conditions, general management level, irregular forest phase and annual oil production of 3-5 kg per mu; The third category is the stands with general site conditions, aging and decline, long-term desolation and oil production of 2-3 kg per mu; The fourth type of forest is a forest with poor site conditions or mixed with other tree species for a long time, which is in a natural growth state and the annual oil production per mu does not exceed 2 kg. For the first-class and second-class forests, measures such as deep excavation and reclamation, opening bamboo joints, pruning and rational fertilization are mainly taken to improve the yield per unit area. Select forest land with good site conditions and great development potential for the three types of forests and implement improved variety renewal; Four types of forests can be transformed into ecological forests or other forest species according to the requirements of classified management. (IV) Existence of specific technical measures In view of the above reasons, 65,438+00 specific technical measures were put forward and used selectively according to different site conditions and stand conditions. 1. Clean up the forest land, and thoroughly cut down miscellaneous timber forests and economic fruit trees such as shrubs, weeds and host plants in the camellia oleifera forest. For mixed irrigation forest land, it is necessary to clear it all at once, which is conducive to subsequent operations. When clearing the forest land, it is necessary not only to remove miscellaneous irrigation, but also to cut off the old, disabled and diseased plants of Camellia oleifera. 2. Soil improvement Low-yielding forests are mostly in the wild, with extensive management and long-term barren or semi-barren. The forest land is barren, miscellaneous irrigation is overgrown, the soil is hardened, and the yield is reduced. Through deep excavation and reclamation, all the miscellaneous shrub trees are dug away, which can inhibit the growth of weeds and reduce or eliminate the objects competing with Camellia oleifera for nutrients. Reclamation should be comprehensive and the depth of reclamation should be greater than 20cm. Only deep digging can be really effective, and the purpose of improving soil cannot be achieved if the depth is not enough. Reclamation method is the same as new afforestation. 3. The horizontal slub ditch with the function of water and fertilizer conservation can make the runoff of the whole slope form a segmented interception pattern, which not only prevents the surface runoff and increases the underground runoff, but also can store water to prolong the underground runoff time, improve the soil water content and stability, and at the same time can block some surface soil and forest litter and prevent nutrient loss. To organize a professional team in the slub ditch, pay off according to the mountain to ensure the reasonable setting of the rules of the horizontal slub ditch. Dig a bamboo ditch along the horizontal line around the mountain. The bottom of the ditch is 50 cm wide and 40 cm deep. The length of the ditch depends on the terrain, which can be long or short. It should be determined on the principle of minimum labor input, but not too short. Generally, it is required to be above1.5m. If it is too short, it will not become a ditch, but a hole. The spacing of ditches depends on the slope of the forest. The spacing between upper and lower ditches with a slope greater than 15 degree is 8m, and the spacing between ditches below 15 degree is 10m. The last slub ditch should be set 7 ~ 8m below the top of the mountain, and the next slub ditch should run 4 ~ 5m above the edge of camellia oleifera forest at the foot of the mountain. 4. Density control Camellia oleifera is due to natural germination and regeneration, man-made destruction or diseases and insect pests in the long-term growth and development process. As a result, the forest stands have been under one roof for generations, and the good and the bad are mixed, and the forest is chaotic. Stand density is too high, branches and leaves are staggered, squeezing each other, not only? It causes mechanical damage to each other, and more seriously, it causes excessive vertical growth, weak reproductive growth and competition for space, which affects the yield and quality of tea oil. It is necessary to cut down trees with unreasonable tree structure, trees with poor fruit or trees without fruit, and young trees under the forest. Through thinning, the canopy density is adjusted between 0.7 and 0.8 to maintain a reasonable light transmittance in the stand. For the open space in the forest or the place where the density is too thin, replanting should be carried out to make full use of soil fertility space and improve the yield per unit area. Replanting should use more than 2 years of camellia oleifera seedlings. Remember to dig nearby small trees and seedlings for replanting. Every year, while reclaiming, shoveling and fertilizing, special management is carried out to replant young trees and promote their rapid growth. 5. Due to the long-term desolation and neglect of management, the crown of the tree is closed and chaotic, and the branches are dense and overlapping, and there are many branches such as overgrowth, germination, pests and diseases, overlapping branches, weak branches in the cavity, waste branches and drooping branches. These branches affect operations such as reclamation, fertilization and ditching; Consumption of nutrition bears no or little fruit; Some affect the ventilation and light transmission in the forest, forming pathogen carriers. So it needs pruning. The pruning method is the same as that of newly planted Camellia oleifera. 6. Rational fertilization Camellia oleifera has been barren for a long time, extensively managed, with poor growth and low yield, which has a lot to do with the serious lack of fertilizer in the soil. Therefore, comprehensive reclamation and applying a certain amount of fertilizer are the key technical measures to greatly increase the yield of Camellia oleifera. The following principles can be followed when fertilizing: P and K fertilizers are the main fertilizers in the new year. Nitrogen fertilizer is mainly used in small years; Organic fertilizer is mainly used in autumn and winter, and quick-acting fertilizer is mainly used in spring and summer; Give more to big trees and less to small trees; High-yield trees are applied more, and trees that bear no fruit or little fruit are applied less or not; Trees with strong growth should apply less N and more P and K fertilizers, while trees with weak growth should apply more N fertilizers. P and K fertilizers should be applied to stands with good site conditions and strong growth potential, and N fertilizers should be applied to trees with poor site conditions and weak growth potential. The amount of fertilization is 20 ~ 3 okg/ mu of urea, 40 ~ 60kg/ mu of phosphate fertilizer, 65,438+00 ~ 20 kg/mu of potash fertilizer, and more than 500kg of organic fertilizer per mu. Fertilization method is the same as new afforestation of Camellia oleifera. 7. Replace inferior plants. Stand with poor variety type, aging trees and low productivity. Inferior plants can be roughly divided into two types: one is that there are few fruits due to old age, infirmity, growth decline and unreasonable tree structure. The other is due to poor genetic basis, good growth potential, vigorous vegetative growth and reasonable tree structure, that is, no fruit or less fruit. For the former type, the inferior plants should be removed when clearing the forest land, and the improved varieties should be replanted and replaced in the pit. For the latter, the crown can be replaced by grafting big trees. 8, prevention and control of pests and diseases, to implement the principle of "prevention is more important than treatment", based on afforestation technical measures, biological measures and drug control, comprehensive prevention and control. Strictly master the technical standards of forest thinning, pruning and forest land cleaning. Intergenerational thinning should be reasonable, and all the old, weak, sick and residual plants should be cut off to completely eliminate germs. Nitrogen fertilizer should be applied in moderation. Especially for stands with good site conditions and vigorous growth, less nitrogen fertilizer should be applied to prevent excessive growth of nutrients, which is conducive to the occurrence of diseases and pests. 9. Camellia oleifera pollinated by bees is an insect-borne cross-pollinated plant. There are more than 5O kinds of insects that can pollinate Camellia oleifera flowers, such as bees, flies and ants, among which the best pollination effect is the native bee. In order to fully protect the soil bees, the soil bees emerge from lO to165438+1late October, so don't smoke, burn soil ash or spray pesticides in the forest. Artificial bees have pollination function, but the nectar concentration of Camellia oleifera is high, which is toxic to bees, so it is not suitable to keep bees in Camellia oleifera forest. 10, timely harvest and strict harvest time. The seeds of cold dew should be harvested before and after the cold dew festival, and the first frost type should be harvested before and after the first frost festival, generally in the "first three and then seven" of the solar term. All localities should conclude village rules and regulations, unify the picking time, and prevent the disorderly picking of tea fruits and premature picking. (5) High grafting can be used to transform the plants in the third forest or the first and second forests. This method is suitable for changing the crown of big trees. It is a technology of grafting first and then breaking the rootstock. Easy to operate and restore the tree potential. Widely used in cutting seedling and high-yield demonstration forest construction, collection of germplasm resources and cultivation of ornamental camellia sinensis.