Eucalyptus is a tropical tree species. Climate (temperature) conditions are closely related to the success or failure of introduction when it is introduced to subtropical areas with high latitudes. Therefore, special attention should be paid to the introduction of provenances with similar latitudes or similar latitudes. Jiangxi can popularize the natural hybrid varieties of Eucalyptus rubra selected in this province since 1976, such as the second generation of Eucalyptus Dayu No.5, 10 DBH 42.8cm, and the height is 21m; "Eucalyptus Chijiang No.8", 23 years old, DBH 58.8 cm, 24 meters high. Guixi 1 Eucalyptus discovered by Australian experts in Guixi Smelter in 1988 has a DBH of 17cm and a height of12 m.. 199 1 year 65438+At the end of February, guixi city was hit by a low temperature of -9.2℃, and the annual "Guixi 1 Eucalyptus" withered, leaving only new branches and leaves, with an average growth of 1.9 m; Most of Camptotheca acuminata, Eucalyptus verticillata and Eucalyptus globulus were frozen to death. Cutting promoted the average height growth of young trees after germination to 2.3 m, 2 m and 1.95 m respectively. These improved varieties were introduced and cultivated in Jiangxi, Hunan, Hubei, Anhui and Jiangsu.
In recent years, Gannan introduced Eucalyptus grandis, Eucalyptus urophylla and Eucalyptus urophylla from Guangdong, with a planting area of over 654.38+10,000 mu. Jishui county in central Jiangxi province was also introduced. 1In the spring of 1999, Eucalyptus grandis and Eucalyptus grandis introduced in Jishui County suffered severe freezing injury at -5.7℃ on February 23rd of that year. After stem cutting and fertilization in the following year, the height growth of young shoots reached 3.5 meters and 3.6 meters respectively, and the forest phase recovered rapidly. Therefore, in the case of freezing injury, it is feasible to take management measures such as flat stubble fertilization to build a short-term industrial raw material forest.
First, the south is suitable for selecting improved varieties.
(1) Red Eucalyptus
Eucalyptus urophylla is native to the Australian outback, with wide adaptability, drought resistance, barren and periodic flooding resistance, strong cold resistance and germination ability, and is suitable for all kinds of soil growth. It grows vigorously on alluvial soil with PH value of 5 ~ 5.8. It grows well on heavy red soil. It has the characteristics of early rapid growth. Under normal circumstances, the growth peak of tree height and DBH is 4 years after afforestation, and the growth peak of tree height in a year is 5-65438+ 10 month, accounting for 70% of the annual growth. After six years' reclamation, the hilly land in guixi city, northeast Jiangxi, has an average height of 8.3m, DBH 14cm, and the average annual cumulative growth per mu 1.4 1 m3.
(2) Eucalyptus grandis
Eucalyptus grandis has faster growth rate and stronger germination ability than Eucalyptus rubra, but its cold resistance is poor, so it is suitable for cultivation in southern Jiangxi. Eucalyptus grandis was introduced to Jishui County, Jiangxi Province in 1999. In June of that year, container seedlings were planted. By the middle stage of 12, the average tree height was 2.5 meters, and the highest was 3. 1 meter. After suffering from severe low temperature, most of them suffered from severe freezing injury. However, after timely mowing and drying, they were nursed and topdressing in the spring of the following year. In May, they removed the sprouting plants (leaving a strong seedling). 1 year and 3 months later, the average height is 3.5 meters and the average DBH is 5.7 cm. By the beginning of 2005, the average 6-year-old trees were as high as15m, and the average DBH was14cm, which could be cut into fibers.
(3) eucalyptus globulus and eucalyptus globulus; E.maidcnii)
Eucalyptus globulus is the earliest eucalyptus named and introduced. Eucalyptus globulus and Eucalyptus globulus (Eucalyptus bicolor and Eucalyptus pseudoglobulus) are closely related, so it is called Eucalyptus globulus group. Eucalyptus globulus is fast-growing, cold-resistant and adaptable, which is suitable for development in low mountainous areas south of central Jiangxi. Jiangxi introduced eucalyptus globulus from Yunnan in the spring of 1993. It was planted in containers that year, and 200 mu was planted in June. After two years of investigation, the average tree height is 4.2 meters and DBH is 3.96 cm. The investigation of the best sample plot (downhill) shows that the average tree height and DBH are 17.438+0 m and 6.9 cm, respectively. According to the cold tolerance test of this variety in guixi city, Jiangxi Province, at the low temperature of -7℃, the leaves withered and the main tips were frostbitten. Slight frostbite at -6℃; Normal growth at -3.7℃. This variety is easy to bleach and has high pulp yield, so it is an important tree species for producing fiber raw materials. High-grade aromatic oil can be extracted from leaves, and the oil content of adult leaves is 2% ~ 3%. At present, Eucalyptus globulus is widely used as oil forest and timber forest in Guizhou, Yunnan and Sichuan.
(4) Round-toothed snakehead, also known as round-toothed snakehead.
Big tree, the original tree is more than 25 meters high, DBH is 2 meters, the trunk is straight, and the dry wood is half the height of the tree. Drought resistance is stronger than Eucalyptus grandis and weaker than Eucalyptus rubra, and it likes acidic soil growth. Eucalyptus tenuifolia introduced from Kennedy River in Australia in Yangjiang, Guangdong is the best, with an average height of12m, DBH10cm and a volume of 8.68 cubic meters. In Yudu County, Jiangxi Province, 1903 was introduced by French missionaries. The 82-year-old DBH 1 10cm tall tree.
Eucalyptus tenuifolia has a wide range of uses, and wood is used as raw materials such as pulp, fiber and particleboard. Tannin can be extracted from bark, and essence can be extracted from leaves. Flowering period is a good source of honey.
Second, promote container seedling raising.
Container seedlings have the advantages of high survival rate, short seedling raising time, low cost and prolonged afforestation season, and have been widely popularized throughout the country.
(1) Seeding container seedling raising
Seedling raising is generally divided into two steps, that is, sowing in the nursery first, and transplanting the seedlings into nutrient bags for cultivation when the seedlings grow 3-4 true leaves and the height of the seedlings is 3-5 cm.
1. Before sowing, soak the seeds in 0.5% potassium permanganate solution for half an hour for disinfection, take them out and drain them, then soak them in GGR6 (commonly known as ABT6) solution (1 g GGR6 plus 4 kg of water) for 4 hours to accelerate germination, and then sow them after filtering.
Afforestation in early spring can be sown in late September of the first year, and afforestation in May and June can be sown in late February to early March. Choose a sunny day or a cloudy day, mix the seeds with 2-3 times of sieved fireclay and spread evenly. The sowing amount of Eucalyptus rubra, Eucalyptus tenuifolia and Eucalyptus longan per square meter is 25-30g; Eucalyptus globulus and Eucalyptus globulus are sown 50 ~ 100g per square meter. After sowing, it is advisable to cover with fine soil without seeds. Then cover the bed with pine needles or thatch to avoid seeing the bed soil, and spray water to moisturize it. After sowing, build an arched insulation bed with plastic film frame.
Emerge 4 ~ 7 days after sowing. When 80% of the new buds are exposed, the mulch is removed in batches. When the seedlings grow 2-4 true leaves and the height of the seedlings is 2 cm, spray 0.5% urea every 5-7 days for 2-3 times. When the height of seedlings is 3 ~ 4 cm, all the plastic films are removed for hardening seedlings. When the seedling height is 5 ~ 6 cm, it can be moved into a container for cultivation.
2. After container seedling seeds are sown, containers, sites and nutrient soil should be prepared at the same time. As far as possible, container seedbeds should be selected in afforestation areas with flat terrain, closed water sources and convenient management. The east-west width of the seedbed is 1 m, and the bed surface is required to be flat. 8 cm× 12 cm plastic film container with holes on both sides should be selected. After filling, cylindrical bags with a height of 10 cm and a diameter of 5 cm will be formed, and 400 bags (plants) will be discharged per square meter. The trail is 60 cm wide and can support16 ~180,000 plants per mu.
Nutrient soil should be made from local materials, and materials with high fertilizer efficiency and good permeability should be selected. Generally, fireclay ash or a mixture of 67% forest topsoil, 30% pig manure (semi-dry) and 3% phosphate fertilizer is selected for composting for 30 days, and then 5 kg of 0.5% potassium permanganate solution is sprayed (mixed while spraying) for disinfection. When bagging, it must be compacted and filled and placed on the set seedbed.
The day before the seedlings are transplanted into the bags, the seedbed and soil container bags should be watered to facilitate the seedlings taking and transplanting. If the taproot of the seedling is too long, you can trim it a little. When transplanting, draw a small hole in the center of the container with a small bamboo stick, transplant one plant in each container, and then press hard. Pay attention to keep the nutrient soil in the bag moist within one week after transplanting; After 10, the seedlings have survived, which can be combined with water application 1% ~ 5% human feces or 0.5% urea solution; After 1 month, compound fertilizer was mainly applied to promote the lignification of seedlings. Spring sowing is prone to damping off, stem rot and powdery mildew due to the high humidity of seedbed. Pay attention to ditch cleaning and drainage, and spray 1: 1: 100 bordeaux solution or 50% carbendazim solution. The cutworm is mainly trapped or captured artificially by cabbage leaf bait at night.
After 40 days of transplanting, the seedlings can leave the nursery when they grow to about 25 cm. Two weeks before leaving the nursery, topdressing, water control and seedling hardening should be stopped, that is, the soil next to the container seedlings should be torn, the containers should be moved one by one, and the main roots should be cut off to promote the growth of lateral roots. Container seedlings should be kept dry, wet and wet. If they wither, they must be watered in time.
(2) Cultivation of cutting container seedlings
In order to maintain the excellent genetic characteristics of eucalyptus and solve the problems of differentiation of advantages and disadvantages, uneven stand, poor quality and low yield caused by improved variety breeding, superior trees are usually used to cut off sprouting strips or super seedlings in nurseries, and a provenance scion nursery is established for tissue culture or cutting seedlings for afforestation. Tissue culture can be used for industrial seedling raising, which can provide a large number of high-quality seedlings in a short time, but it is technically difficult and costly. At present, cutting seedling raising is mostly used.
1. Insert the bed to build a simple shade shed with a height of 2 meters and a light transmittance of 40%. In the shed, a number of hotbed frames with east-west length 10 m and internal width 1 m are made of bricks, with walls 40 cm high and north walls 50 cm high; 3 cm water holes are left at the bottom of the north and south walls every 50 cm, and a small mouth is symmetrically left at the top every 50 cm to place wooden sticks to support the agricultural film; The bed bottom is padded with pebbles and 15cm coarse sand, and then the bed surface is covered with sterilized river sand with a particle size of 0.2 ~ 0.3cm (disinfected with 1% potassium permanganate for 4 hours and then washed with clear water) with a thickness of 15cm ~ 20cm.
2. Cutting treatment and planting. Collect robust, semi-lignified sprouts from the cutting nursery of provenance, put them into clean water, cut them into 6- 10 cm in time, leave two leaves at the top, cut off 1/2- 1/3 leaves, and cut off other leaves (more than two leaves can be left at the top of super seedlings). Disinfect15min in 0.2% permanganate solution (i.e., dissolve 1g powder in 5 kg warm water), drain water slightly, and then soak in GGR6 solution (i.e., soak1ggr6 in 2 kg water) for 5min10min, and take out sticky talcum powder or powder. The row spacing is 3cm× 3cm, the cuttings are cut vertically, and the depth is about 1/2. After manual compaction, cover the plastic film in time, keep the temperature at 20℃ ~ 30℃ and the relative humidity at 85% ~ 95%. When the temperature exceeds 30℃, demould and ventilate; If macula is found, spray 0. 1% Baijunjing in time. Cuttings that germinate young roots after 10 ~ 15 days can be moved into container bags for culture. When the young roots of container seedlings grow to 5 ~ 10 cm, it is necessary to uncover the film and practice the seedlings. After about 30 days of cultivation, the seedlings can be taken out of the nursery for afforestation when the height is 25 ~ 30 cm.
Third, container seedling afforestation
(1) Planning and selection of afforestation areas
According to the differences of geographical latitude, climate and eucalyptus adaptability, Jiangxi can be divided into three regions;
1. The annual average temperature in most parts of southern Jiangxi is above 18℃, with historical extreme low temperature of -3℃ ~ 5℃ and extreme low temperature of -2℃ ~ 4℃ in recent 14 years. Therefore, 13 counties (cities) south of Doudu, Shangyou and Ruijin are suitable for developing fiber raw material forests. In recent years, Hong Kong Guangjin Group, Zhejiang Luyuan Company and Jiangxi Hongwei Company have settled in and developed, and built a large area of eucalyptus grandis and eucalyptus grandis base forest.
2. The south of 27 degrees north latitude includes Shicheng, Ningdu, Xingguo and Chongyi counties in Ganzhou, Jishui, Taihe, Wan 'an, Suichuan, Yongxin, Jizhou, Qingyuan and Ji 'an counties in Ji 'an, and Nanfeng, Guangchang and Cheng Nan counties in Fuzhou, with an annual average temperature of 17℃~ 18℃. The extreme low temperature in recent 14 years is -2℃ ~ 5.8℃, which is suitable for developing fiber timber forest and diesel forest. The varieties should be Eucalyptus rubra cultivated in this province and Eucalyptus grandis, Eucalyptus grandis, Eucalyptus urophylla and Eucalyptus tenuifolia cultivated in South China. Eucalyptus yunnanensis can be selected in mountainous areas.
3. Because there is Wang Huai in the north of guixi city in the northeast of Jiangxi, the cold air is not easy to soak, which forms special climatic conditions. The annual average temperature is 65,438 08℃ and the annual rainfall is 65,438 0900 mm, including Yuehu in Yingtan City, yujiang county County, Yiyang in Shangrao City and Jinxi in Fuzhou City, which is suitable for developing timber forests, timber forests and oil forests. The varieties are selected from local eucalyptus urophylla varieties, and eucalyptus urophylla in South China, eucalyptus tenuifolia and eucalyptus globulus in Yunnan can also be introduced.
In addition, Shangrao, Dongxiang and Nanchang in northeast Jiangxi, Yichun and Xinyu in northwest Jiangxi and south of the first line, it is also successful to choose Eucalyptus rubra for afforestation on sunny slopes or under mountains and nests. For example, Eucalyptus guixi introduced by Nanchang Changbei Jiangxi Academy of Forestry 1989, 199 1 suffered a once-in-a-century cold injury at the end of February, and the average height of 13 was 16 ~ 65438 after cutting and regeneration.
(2) Planting density and soil preparation
1. The afforestation density is generally per mu 1 10 ~ 170 plants, and the plant spacing is 2m× 3m or 2m× 4m. There are 200 ~ 300 trees per mu in the dual-purpose forest for wood and oil, with the row spacing of 2m× 1.5m or1.5m×1.5m. Oil and wood can be steamed after cutting in the early stage and cultivated into fibers or large-diameter timber in the later stage. There are 300 ~ 400 oil-bearing forests per mu, with row spacing of 1m× 2m or 1m× 1.5m, and low-growth forests are managed.
2. Eucalyptus is a deep-rooted tree species and grows well in deep, loose and fertile soil. Deep ploughing and soil preparation is the key measure for afforestation in low hills of red soil.
Soil preparation should be carried out 3 months before afforestation, using large holes for soil preparation, with specifications of 50 cm× 50 cm× 40 cm or 60 cm× 60 cm× 50 cm, and the topsoil and subsoil should be stacked separately. In places with flat terrain and good conditions, it is best to prepare with grooves. Trenches should be dug along contour lines, with a width of 50 cm and a depth of 40 cm.
Eucalyptus is sensitive to phosphorus and potassium fertilizer, so we should bury about 1 kg grass at the bottom of each hole, and then return the topsoil to the hole. At the same time, 0.3 ~ 0.5 kg compound fertilizer is applied in the middle of the hole, and then the soil is filled. Or apply 0.5 ~ 1.0 kg compound fertilizer in the middle of each hole, mix it evenly with the soil, and then fill it up to 5 cm above the surface.
(3) container seedling cultivation and afforestation
It is best to choose cloudy days or sunny days after rain for afforestation. When planting seedlings in plastic bags, they should be placed horizontally in the means of transport to prevent the stems from breaking. When planting, first dig a hole slightly larger and deeper than the soil of the container bag in the center of the hole, put the container seedlings with film, straighten and tamp the loose soil around them, and then fill it up until the soil of the container seedlings is covered.
(4) Tending management and thinning
Generally, it will be closed for 2-3 years after afforestation. In the young forest stage, in addition to weeding, chopping wood and loosening soil in time before enclosure, compound fertilizer with high phosphorus and potassium content should be applied, and 0.5 kg should be applied to each hole. Eucalyptus timber forest is generally not thinned, but timber forest and oil forest must be thinned for 3 ~ 4 years, and tender branches and leaves can extract oil. Cultivate large-diameter timber as the target stand, thinning it in the fourth year after planting, and keep it less than 100 plants per mu. At this time, it is in the period of vigorous growth, and 0.5 kg compound fertilizer is applied to each hole after thinning. For oil-bearing forests managed by dwarf forests, 30-50 kilograms of compound fertilizer should be applied per mu after each branch is harvested.
(5) Cutting and regeneration
1. Under the condition of intensive management, the cutting age is the fastest growing period from 4 to 6 years after afforestation, and the average annual growth and annual growth both reach the peak. Therefore, as the raw material forest of pulp and fiberboard, it can be cut in 5 ~ 7 years. It generally takes 15 ~ 25 years to cultivate large-diameter timber forests such as plywood. Oil-bearing forest, which is dominated by oil refining, is managed by dwarf forest, and tender branches and leaves can be collected 1 ~ 2 times a year after the second year.
2. Cutting method In order to facilitate cutting and regeneration, block cleaning can be used. Before cutting, the cutting design should be done well, and the height of cutting pile should be reduced as much as possible. The cutting height of medium and small diameter timber is controlled at 5 ~ 7 cm, and the cutting height of large diameter timber is controlled at about 10 cm.
3. Eucalyptus in-situ regeneration has strong germination ability, and the germination regeneration can be carried out for 2 ~ 3 generations. After cutting for about 20 days, more than 95% of the stumps will grow adventitious buds, and each stump has more than 10 buds, which grow rapidly and have a straight shape, but the wind resistance is poor. When the buds grow to 50 cm high, they should start to sprout and leave strong strips to set the plants. During the first tillering, 2 ~ 4 plants were planted on each stump, and the tillering was removed for the second time, and 1 ~ 2 dominant tillering strips were left on each stump. Germination grows fast and aging is fast. It is necessary to loosen the soil and topdressing at least twice in time, each topdressing is 0.5 kg per cut.