Morphological features

Dense shade large tree, 20 meters high; bark persistent, dark brown, 2 cm thick, slightly soft and loose, with irregular oblique cleavage grooves; shoots angular.

Eucalyptus

Juvenile leaves opposite, blade thickly leathery, ovate, 11 centimeters long, up to 7 centimeters wide, stalked; mature leaves ovate-lanceolate, thickly leathery, unequal in side, 8-17 centimeters long, 3-7 centimeters wide, lateral veins numerous and conspicuous, gently slanting toward the margins at an 80-degree open angle, glandular dotted on both surfaces, with the intramarginal veins 1-1.5 millimeters from the margins; petiole 1.5-2.5 centimeters long.

Umbels stout, with 4-8 flowers, the peduncle compressed, within 2.5 cm; pedicels short, not more than 4 mm long, sometimes longer, thick and flattened; buds 1.4 -2 cm long, 7-10 mm wide; capsule hemispherical or obconical, 7-9 mm long, 6-8 mm wide; capitulum about as long as the calyx tube, the apex contracted into a rostrum; stamens 1-1.2 cm long, anthers elliptic, longitudinally divided.

Capsule ovate-potentate, 1-1.5 cm long, slightly contracted in the upper part, slightly enlarged at the mouth of the capsule, with 3-4 petals, y hidden in the calyx tube. Flowering period April-September.

Environment

Born in sunny plains, slopes and roadsides. Leaves are harvested throughout the year. It is cultivated in southern and southwestern China. The trunk is high, the root system is developed, and the transpiration is also large, known as the water pump, easy to cause soil sand, not conducive to the growth of other plants. Generally able to grow in areas with annual precipitation of 500 millimeters, annual precipitation of more than 1,000 millimeters of growth is better.

Born in acidic red soil, yellow soil and deep alluvial soil, but grows well in deep, loose, well-drained soil. The main root is deep and strong wind resistance. Most of the root necks have wood tumors, with the role of storing nutrients and sprouting renewal. Generally 3~4 years after afforestation can be flowering and fruiting.

Distribution

Eucalyptus is native to most of the Australian mainland, with a few growing on the neighboring islands of New Guinea and Indonesia, as well as the Philippine archipelago, where it was introduced in the 19th century, and as of 2012, it is cultivated in 96 countries or regions. The main distribution center is in Oceania, and there is a certain amount of distribution in Fujian, Guangxi, Guangdong, Yunnan and Sichuan in China.

Eucalyptus is diverse, adaptable and versatile. It grows in a wide range of environments, from the tropics to the temperate zone, with -18℃-resistant Eucalyptus dichromaticus, Eucalyptus gunni and -22℃-resistant Eucalyptus snow. It can grow in areas with annual precipitation of 250-4000mm, from coastal to inland, from plains to high mountains (2000m above sea level). Its body shape also varies greatly, including the world's rare tree height of 100 meters of large trees, there are also short and multi-stemmed bushes, and some both drought-resistant and flood-resistant tree species.

Species classification

There are dry sclerophyll forest types, wet sclerophyll tree types, savanna types, dry sclerophyll tree types, and alpine meadow types.

Eucalyptus has a wide variety of species, with 522 species and 150 variants. The five species that can be planted are blue eucalyptus, straight-drying blue eucalyptus,

lemon eucalyptus, large-leaved eucalyptus and leaf-viewing copper eucalyptus.

Reproduction Methods

Reproduction by seeding, grafting, cuttings and stem tip tissue culture.

Pictures of Eucalyptus(3) Cultivation techniques Land preparation

Usually manual, mechanized land preparation has been greatly promoted, which has obvious effects on the improvement of land preparation efficiency and effectiveness. However, it also has a certain impact on the ecological environment of eucalyptus forests, and eliminates many beneficial organisms in the process of eliminating weeds. Land preparation can improve the physical and chemical properties of the soil, make the soil permeable, effectively remove weeds, enhance the soil water storage capacity, and the effect of land preparation is especially obvious on the soil of slaking. In the young forest stage, land preparation can increase the conversion rate of soil fertilizer, reduce the resistance of root growth, so as to improve the growth rate of seedlings.

Digging pits

Planting density has a very important impact on the final yield of eucalyptus, and digging pits determines the final cultivation density. When digging pits, according to the fast-growing eucalyptus planting years and varieties of growth characteristics to determine the spacing of digging pits, to ensure that eucalyptus in the growth of reasonable permeability, but also to avoid wasting soil fertility due to planting density is too small. Usually, the density of digging pits can be 3m×2m, digging pit specifications for 1250px×1250px×1000px, zigzag arrangement. In addition, it is necessary to prevent soil erosion caused by digging pits, so that the first land, after digging pits, and the depth of the bottom of the pit should be deeper than 1000px.

Fertilizer

Fast-growing eucalyptus fast-growing growth rate, the demand for fertilizer is also higher, so the reasonable application of fertilizers is very critical to improve the growth rate of eucalyptus trees. When applying fertilizer, we must grasp a basic principle: to pursue the minimum amount of fertilizer under the premise of satisfying the growth of eucalyptus. Therefore, in the study of fertilization technology, not only to study the specific method of fertilization, but also to determine the fertilizer required by the plant.

First of all, we should pay attention to the use of base fertilizer, base fertilizer is usually fermented municipal waste or stable manure, these fertilizers have a slow-release, so you can apply fertilizer 1 month before planting, in the backfill can also be applied in the form of a hole in the ammonium phosphorus and potash fertilizers and organic fertilizers mixed with the applicator. It should be noted that the root system of young eucalyptus is relatively fragile, so it is important to avoid direct contact of fertilizers with the root system of young seedlings, which may lead to root burning. Fast-growing eucalyptus trees need more fertilizer in the first three years, can be 40 days after the first application of fertilizer for the first time, if the first application of fertilizer contains more nitrogen, then you can delay the first time of fertilizer. Subsequent fertilization should be based on the growth of eucalyptus trees, especially the degree of canopy depression to determine the timing and amount of fertilizer. In addition, in order to avoid the forest weeds compete for fertilizer, must be timely weeding operation.

Planting

After preparing the ground and implementing the base fertilizer, it is necessary to choose the right time to plant. Spring temperature is suitable, rainfall is abundant, eucalyptus saplings have a high survival rate, is more ideal time for afforestation. When planting, first of all, we should choose robust seedlings, and carry out disease and insect prevention treatment, keep the seedlings moist, and do bag removal, deep planting and compaction during planting. Subsequently, replanting should be done according to the survival rate of eucalyptus saplings.

Cultivation

According to the saplings in the 3~6 months after the successful planting, the growth is still weak, in order to ensure that the seedlings can have sufficient light and nutrients, pay attention to the removal of weeds, to avoid competition with the saplings for the growth of the elements, and in the spring is the peak season of the growth of weeds, weeding is a must. At the same time, in order to ensure the release of soil fertility, but also loosening operations, in the operation should pay attention to the roots of the saplings to maintain a certain distance, to avoid harming the end of the root.

Eucalyptus pictures(4) Disease and Insect Control

Disease Prevention

Scorch blight, green blight, stem rot and gray mold are common diseases of fast-growing eucalyptus.

Scorch blight is mainly characterized by gray-green water stains at the junction of healthy tissue and diseased spots, and the leaves dry up and fall off quickly. Green blight can occur throughout the growth cycle of fast-growing eucalyptus, mainly manifested as part or all of the leaves are water loss wilting, dry, drooping, and will die within a few days. Stem rot is characterized by white, watery spots at the base of the stem, which turn brown and black. Gray mold is manifested by the formation of fungal mold on the surface of the plant. The prevention and control of fast-growing eucalyptus diseases should adhere to the policy of prevention first and combination of prevention and control. First of all, it is necessary to carry out thorough disinfection in the planting process, to prevent and control the disease germs from being brought in with the seedlings, and also to maintain the normal drainage system in the planting area, to cut off the path of disease propagation. Attention should also be paid to rational fertilization. In addition, you can also choose Bordeaux liquid, Chlorothalonil, methotrexate and other chemical agents to sterilize.

Pest control

Soil-dwelling termites are common pests of fast-growing eucalyptus, usually occurring in the young forest stage, the termites firstly jeopardize the rootstocks of the young plants, and then turn to the surface and the ground and along the topsoil and stripping of the main root and the inverted root, and ultimately, the seedling can't deliver nutrients and die. The prevention and control of termite infestation should be based on prevention and baiting. During afforestation, 3~4g of carbofuran can be placed in the holes and mixed with soil fertilizer to fill the holes, 0.35kg of the drug can be used per 667m 2. After afforestation, 2g of carbofuran can be placed 5m away from the pocket of the tree, 0.22kg of the drug can be used per 667m z. Attention should be paid to avoiding the contact of powder with the saplings, which will lead to the drug damage. Fast-growing eucalyptus is one of the fastest-growing tree species in the world, reasonable cultivation techniques to improve eucalyptus yield is of great significance, fast-growing eucalyptus planting and management of each link will affect the final yield, the use of scientific planting techniques, and to strengthen the control of pests and diseases, will be able to achieve the purpose of rapid yield increase.

Weed prevention

Manually laid 5 silk thick 1 m2 black film paved with soil around the edge of the good, to the wind does not open shall prevail. Or use thinner agricultural film (1 × 1 or 1.5 × 1.5), it is recommended that the use of 1.2 ~ 1.5 m wide film into a band to lay more labor-saving time. According to estimates: 1 m2 black film (non-biodegradable) the cost of 0.35 yuan per plant; the use of agricultural mulch (biodegradable) the price of 0.16 yuan per plant, the life of the general can be up to 10 ~ 12 months. The use of agricultural mulch in the use of this method within a year without the need to weed, but also has a very good insulation, water retention, insect prevention role.

Eucalyptus alternative trees

Although eucalyptus grows very fast and has a wide range of timber uses, eucalyptus biology has been criticized by experts and scholars in the forestry industry. The rapid growth of eucalyptus is accompanied by the deterioration of the local ecological environment. Its growth process requires a lot of water resources, and large-scale planting will lead to a decline in the water table under the local area and a reduction in the water retention capacity of the soil, which in the long run will lead to land condensation and even soil sanding. Eucalyptus has a huge demand for fertilizer in the soil, and where eucalyptus has been planted, the fertility of the land will be reduced to different degrees or even depleted, which is why eucalyptus has been nicknamed the "overbearing tree". New varieties of eucalyptus are needed to replace the planting of eucalyptus.

Eucalyptus

The trees used to replace eucalyptus planting are fir, pine, Hong Sen acacia.

Introduction of alternative species

Fir

This family of plants is evergreen, semi-evergreen or deciduous trees with straight trunks, large branches in whorls or near whorls, longitudinally cracked bark, and longitudinal strips falling off; the leaves, bud scales, stamens, bract scales, bead scales, and seed scales are all spiro-turned in a row, and rarely interact with each other (Metasequoia spp.). Leaves lanceolate, subulate, scalelike, or linear, homotypic or dimorphic on the same tree. Bulbous flowers unisexual, monoecious; male bulbous flowers small, solitary or clustered at branch apex, occasionally in leaf axils, or arranged in terminal racemelike or paniculate inflorescences, stamens with 2-9 (usually 3-4) anthers, pollen globose or slightly flattened, without air sacs, with a conspicuous or inconspicuous *** shaped protuberance on distal surface; female bulbous flowers terminal, bulbous scales and bracteate scales mostly united or completely united, or bulbous scales very small, or bracteate scales degraded, bulbous scales on ventral surface, rarely interacting with each other. The ovules are reduced, and the ventral base of the bulbous scales has 2~9 erect or anatropous ovules. Seed cones ripening and dehiscing in one year or the next, seed scales (or bract scales) flattened or peltate, woody or leathery; seeds flattened or three-angled, narrowly winged around or on both sides, or long-winged proximally; embryo with 2~9 cotyledons. The chromosome base is mostly x=11, sparsely 10 or 33.

Acacia Hong Sen

Tall tree, narrow crown type, its trunk form rate can reach 0.78; the trunk is straight and upward, the crown is compact and complete, the angle of the branch is 30-45 °, and the branches are evenly distributed within the crown to form a complete crown. Height to about 25 m, bark brown or light gray, simple pinnately compound leaves, compound leaves 25-40 CM long. leaves alternate; 7-12 CM long, petiole 1-3 cm long, leaf blade 4-7 CM wide, base expanded; elliptic to long ovate, or oblong lanceolate, apex rounded or obtuse head, sometimes slightly concave, with small fine spiny tip, entire, smooth or pubescent when young, leaf texture thick, bright green. Inflorescences axillary, flowers white, very fragrant, densely built into racemes, as pendulous, 10-20 cm long, axes hairy, pedicels 7 mm long, densely hairy; corolla butterfly-shaped, consisting of flag petals, winged petals and keeled petals, which flag petals have a yellow spot at the base; 102 bodies of stamens; the ovary cylindrical, stigma capitate, flowering in early summer.

ICPR

Pine

The crown of the pine tree is pyramidal when it is younger, and the branches are more whorled. Seedling out of the ground, after the cotyledon unfolded, the first born for the primary leaves, solitary, screw-turned arrangement, linear lanceolate, leaf margin with teeth. Primary leaves exercise the function of leaves for 1~3 years before the emergence of needles, usually 2, 3, 5 in bundles, bearing the tip of short branches. Each bundle of needles has a leaf sheath at the base, which is shed or persistent at an early stage. The position of the resin tracts in the leaf tissue is relatively constant in adult plants and can be divided into three types: exogenous, mesophytic, and endophytic. One or two vascular bundles are visible in cross sections of pine needles, and vascular bundles may be combined in double-vascularized pines under special circumstances. Bulbous flowers are unisexual and monoecious. Seed cones consist mostly of seed scales, which are lignified at maturity. The *** thickened part of the seed scales is called the scale shield, and the verrucose projection at the apex of the shield is called the umbilicus. Some species have spines on the umbilicus, some do not. Seed scales open when the fruit is ripe, the seeds fall off; but a few trees seed scales are kept closed for a long time. Each seed scale has two seeds, the upper part of the seed with a long wing, a few with short wings or no wings.

Crown Red Poplar

Crown Red Poplar, the leaf color from March each year during the germination period of bright red gradually changed to purple red, orange-red, the lower leaves become emerald green, until November each year during the defoliation period of the leaf color and then transformed into bright red and orange, the petiole, leaf veins, stem, the new tops of the always purple-red, in the entire reproductive period to always maintain a tree of three colors.

Eucalyptus seeding of the ban

Huidong County CPPCC member, the Democratic Progressive Party Huidong branch of the main committee Xu Weizhong on the ban on eucalyptus tree proposals, Huidong County Party Committee, deputy secretary of the county, said Xu Yi, Huidong, eucalyptus tree planting people should be "left a little rice to future generations to eat," he said by analogy, eucalyptus tree planting is a kind of "lack of morality tree".

Guangdong proposed legislation reservoir

"Guangdong Province, the implementation of the Chinese People's **** and the State Water Law" approach (draft) "any unit or individual shall not be used to refine the mountain or full reclamation method of renewed afforestation, shall not plant eucalyptus and other unfavorable to water conservation and protection of tree species. The staff of the Department of Water Resources, who were present at the meeting, said that eucalyptus trees had a great impact on water sources, and therefore eucalyptus trees were specifically included in the draft. There are also representatives present to support the practice, that eucalyptus leaves to the reservoir easy to decay easy to produce cyanobacteria, cyanobacteria is a great threat to drinking water. Many members also supported the attitude, but at the same time believe that the scope should be expanded, not conducive to water conservation and protection of tree species should not be planted.

Pearl River Delta

The hazards of large-scale planting of eucalyptus trees are very great, and will lead to land sanding, declining fertility, and inhibition of local native species, the Shenzhen delegates meeting to submit a proposal calling for a ban on eucalyptus planting.

Sanshui

Sanshui District has launched a forest rights reform, clear collective forest land in the ecological public welfare forest by the village collective management management, to maintain its ecological function. For commercial forests, the planting of eucalyptus and other ecologically destructive species is explicitly prohibited.

Main Values Economic Values

China has successfully developed high-performance eucalyptus reorganized timber, eucalyptus veneer laminated timber, bamboo and eucalyptus composite materials, eucalyptus wood composite panels with thick cores, and formaldehyde-free eucalyptus plywood manufacturing technology, which has increased the comprehensive utilization rate of eucalyptus trees to more than 90%.

Eucalyptus not only brings value to industry, but also brings economic benefits to other industries.

Paper and Pulp

Eucalyptus papermaking started as early as the early 20th century. The average length of eucalyptus fibers is 0.75-1.30 mm, and its color, density, and the ratio of extracts are all suitable for pulping. There are also many large paper mills that use eucalyptus for the production of kraft and column printing paper. Eucalyptus wood cellulose, can be made into dissolving wood pulp and then processed into rayon, to have achieved considerable success.

Refining

Eucalyptus varieties include Eucalyptus blue, Eucalyptus straight, Eucalyptus Smith, Eucalyptus grandis, Eucalyptus minor, Eucalyptus ruderalis, and so on. Among them, blue eucalyptus and straight eucalyptus are the main species used to extract eucalyptus oil. Eucalyptus oil contains eucalyptol, which is a colorless or light yellow liquid with a *** cool fragrance, mainly used in toothpaste, mouthwash, food and medicine. Blue eucalyptus, straight eucalyptus tree species is excellent, the use of its branches and leaves to extract eucalyptus leaf oil, the best texture.

Gold Inside

Australian scientists have found trace amounts of gold in the leaves of eucalyptus trees using X-rays, which is believed to be the first time humans have found naturally occurring gold in a living organism.

The scientists found that eucalyptus and acacia trees in western and southern Australia have deep and extensive root systems, and that in times of drought, their roots dig for water, and some reach gold veins, where the roots suck up tiny bits of gold. The roots then dilute the gold and conduct it to the vein system of the tree, which can form larger crystals when a large amount of gold material accumulates at the tips of the leaves.

Scientists further point out that for plants, gold is toxic, so gold is transported to the ends of plants such as leaves, which reduces destructive biochemical reactions.

In addition, the researchers said that the amount of gold contained in the leaves of the tree is very small, 500 eucalyptus trees growing in the gold mining area of the leaves of the gold content may only be enough to create a wedding ring, so this discovery will not bring wealth to the gold seekers. However, scientists point out that the discovery could help people explore for gold in a more environmentally friendly and cheaper way.

Edible value

The roots of the eucalyptus tree can be eaten as well as water. Eucalyptus is also used as fuel in some places. There are many eucalyptus leaves that can be used as fodder.

Medical value

With eucalyptus fresh leaves, eucalyptus oil can be produced by water distillation (oil yield 0.5-1.8%). Eucalyptus mainly contains eucalyptus oleoresin (65-75%). Terpenes, isophora leaf oil, geraniolone, menthone, piperone and other components. It can also be used as a medicinal raw material for oral use, rhinitis, expectorant, cooling oil, wind-repellent cream and so on.

Properties of Chinese medicine

This product is slightly pungent, slightly bitter, flat. It has the function of dispersing wind and relieving heat, inhibiting bacteria and anti-inflammatory, antiseptic and relieving itching. It can be used to prevent influenza, epidemic

cerebrospinal meningitis, upper respiratory tract infections, pharyngolaryngitis, bronchitis, pneumonia, acute and chronic pyelonephritis, nephritis, dysentery, filariasis, and externally to treat burns, cellulitis, mastitis, boils, tannin, dermatitis of paddy fields, wet and itchy skin, and ringworm of the feet, etc. It has been used to treat the symptoms of acute and chronic pyelonephritis. Single prescription

1, the treatment of intestinal mycobacterial disease: eucalyptus leaves, sapium leaves, river mu leaves, three branches of the bitter leaves of 15-30 grams, decoction, 2 times a day, 7 days for a course of treatment.

2. Treatment of acute gastroenteritis: 15 grams of eucalyptus leaves, 10 grams of plucked leaves, decoction.

3. For the prevention of influenza and meningitis: 15 grams of eucalyptus leaves, decoction with water.

4. Treatment of paddy field dermatitis, skin eczema, far away from rotten feet: eucalyptus leaves, neem leaves, lacquer, pine leaves, each appropriate amount of thick decoction external wash.

5. Treatment of cervical erosion: eucalyptus leaves calcined and stored research powder sprinkled on the affected area. (According to gynecological routine medicine).

6. Treatment of pustules, eczema: eucalyptus leaves, neem peel appropriate amount. Decoction external wash, twice a day.

This product is commonly used for internal use 9-15 grams (15-30 grams of fresh products), internal use should not be excessive. Appropriate amount for external use, decoction of water for external washing.

Natural Value

Eucalyptus is a beautiful, evergreen tree with exceptionally rapid growth and strong drought resistance, which is suitable for use as roadside trees, windbreaks and sand forests, and as a greening tree. The leaves of the tree contain aromatic oil, which has the effect of sterilizing mosquitoes and can be refined into fragrant oil, and it is also a good greening species for sanatoriums, residential areas, hospitals and public **** green areas.

Eucalyptus plantation forests are also a huge carbon reservoir. According to research, each hectare of eucalyptus can absorb 9 tons of carbon dioxide per year, while releasing oxygen. Planting eucalyptus on degraded land improves soil structure, increases soil biomass, and improves the microclimate and ecological changes in the afforested areas. Leizhou Peninsula used to be a thousand miles of bare land, environmental degradation, forest coverage of only 8%, in 1954 began to create a large number of eucalyptus plantation forests, the existing eucalyptus nearly 3 million acres, the forest coverage rate of 24%, the ecological environment has improved significantly, and has become an important city of agriculture in South Asia's tropics.

Eucalyptus

The Development Trend of Eucalyptus Mixed Forests

Eucalyptus mixed forests with Hong Sen acacia and poplar can fully utilize the land resources and light resources, and maximize the economic benefits.

Mixed forests are different mixes and matches according to the characteristics of plants' light-loving and shade-tolerant, rooting depth, plant growth cycle and fertilizer-loving, so as to make full use of the land resources and reasonably distribute light, water and nutrients in different layers. Another feature of mixed forests is that the light in the forest is weakened, water evaporation is reduced, which can form a microclimate within the forest Mixed forests have a more developed root system, which will have more effect in retaining water and preventing wind and sand fixation; Mixed forests have a thick leaf canopy, more deadfall, more leaf fall per unit area, which can improve soil fertility more than simple forests; Mixed forests have more varieties, better habitats and more natural enemies of pests and diseases, so that the reproduction and propagation of pests and diseases can be effectively suppressed. Inhibit the reproduction and spread of pests and diseases; Due to the low temperature, high humidity and low wind speed of mixed forests, the risk factor of fire is lower; The main species of mixed forests, with the assistance of the accompanying species, the main trunk can grow to be more through-value, complete, and the quality of the dry timber is better.

High-quality wood

Eucalyptus wood is mostly heavy and hard, with strong resistance to decay, and can be used for construction, sleepers, mining pillars, piles, furniture, matches, agricultural tools, electric poles, fences, and carbon wood.

Hazard

According to the opinions and objective reports from the Institute of Ecology and Environment of the Chinese Academy of Sciences, the Southwest Forestry College of China, the State Forestry Administration, the China Central Television (CCTV), and many other experts and scholars, the hazards of planting eucalyptus on a large scale can be seen in the following aspects:

1. Eucalyptus is a "fertilizer pumping machine"

Eucalyptus is very demanding in terms of fertilizers and nutrients for the soil, and where eucalyptus is planted, the fertility of the land will be greatly reduced, and the soil will be more fertile. The land where eucalyptus trees are planted will experience a decline in land fertility and even depletion, and the original vegetation will be seriously damaged because of the lack of sufficient fertilizers and nutrients, leading to land degradation, deterioration of soil and water conservation, and infertility of the land, which will make the introduction of other plants impossible to survive. The proportion of soil intensity erosion increases year by year, and landslides and floods increase.

2. Eucalyptus is an "overbearing tree"

Eucalyptus is extremely inhibitory to local native, native and indigenous species. When it grows, other species can't grow, and will slowly retreat, eventually causing eucalyptus forests to be bare on the surface, with no grass or shrubs on the groundcover (such as what is commonly known as "mud trees" in their hometowns, "milk root", "chicken poop vines", "honeysuckle", etc.), no small trees, and a variety of herbs and medicines. Other species cannot survive with it. Decay and degradation of native species, extremely single plant species, unable to provide food or suitable habitat for most of the animals, very few or even extinct animals in the forest, very low level of biodiversity, broken biological food chain, very fragile ecology, lack of natural enemies to control pests, easily infected with pests, resulting in large-scale damage, cutting down natural forests and planting a large area of plantation forests with single species of trees of similar age and very dense, which will lead to the "natural forests", which will lead to the "natural forests". Cutting down natural forests to plant large areas of single tree species, similar age and very dense plantation forests will lead to "green deserts"; dry and easy to form fires; and also lead to microclimate changes and other serious ecological crises. The ecology will be devastated and it will be difficult to recover. And not necessarily in two or three years.

3. The chemical products applied to eucalyptus are highly toxic and long-lasting, and eucalyptus gas is *** and toxic

When eucalyptus trees are planted, certain highly toxic and long-lasting chemical products will be applied, and once the products are applied to the land, they will be very difficult to remove cleanly, and they will pollute the water quality greatly, which will cause inestimable harm to people and animals after they drink them. In addition, the eucalyptus tree emits an odor that is *** and toxic to the human body, which will threaten the health of the local people.

Question: Eucalyptus is a "pumping machine" that sucks up water, leading to drought

This is one of the most common questions about eucalyptus: eucalyptus causes a significant drop in groundwater due to the large amount of evapotranspiration, which can cause droughts and depletion of water sources, just like "pumping machines" do. In this regard, the results of scientific research have proved that eucalyptus trees are quite efficient in utilizing water compared with other conifers, and that eucalyptus forests play no less important roles than other tree species in water conservation, soil conservation and climate regulation. A large number of field observation experiments also show that eucalyptus does not directly cause drought. Scientists Bailly and others up to eight years of observation data also show that most of the water in the eucalyptus forests are infiltrated into the soil, but can effectively maintain soil and water.

Question: Eucalyptus is a "fertilizer sucker", leading to "ground exhaustion"

Many people who have been to eucalyptus forests or planted eucalyptus trees have said that eucalyptus trees have a great demand for soil fertilizers and nutrients, but all the eucalyptus planted in the land, the fertility of the land has declined or even depleted, and the soil planted with eucalyptus trees and then planted on the introduction of the other plants simply can not survive. In China, many years engaged in eucalyptus research scientists Bai Jiayu through the measurement of eucalyptus nutrient uptake, found that eucalyptus than other tropical tree species have the ability to efficiently utilize the nutrients; in foreign countries, scientists Liani through the eucalyptus forest soil observation found that eucalyptus in the rapid growth period, will be absorbed during the period of nutrient elements returned to the soil. In fact, the negative effects of "pumping machine" and "pumping fertilizer", most of them only occur in the early stage of afforestation (the first 8-10 years), after which the eucalyptus tree's water storage and fertilizer storage will be gradually reflected.

Question 3: Eucalyptus is a "dominant tree" that inhibits the growth of other species

Some people point out that eucalyptus is extremely inhibitory to local native, native and indigenous species, and that other species cannot survive with it. Indeed, based on scientific common sense judgment, foreign species may indeed cause harm to the native ecological environment. However, scientific studies have also found that almost all harmful alien plants are herbaceous plants, while the ecological harm of eucalyptus, which is a tree, has not yet been truly proven. In addition, it is a normal phenomenon in nature that some tree species are sensitive to the sap or rotting leaves of other species. This has been investigated in the Leizhou Peninsula of Guangdong Province, and the results of the study show that the diversity of local forest flora has not been reduced by the planting of eucalyptus.

Incomplete discussion mechanism, environmental organizations become spokespersons

After this, the eucalyptus "harm" has been continuously amplified, and Greenpeace's reports and data have been widely quoted by many "popular science authors", public figures, and the media. The latest version is the "eucalyptus drought" in the Southwest China drought.

Yunnan, which has a large eucalyptus plantation, *** quickly held a press conference on the rumor, stating that there was no scientific evidence to prove that eucalyptus forests and rubber forests caused the drought, and People's Daily published an interview with official forestry scholars to clarify the doubts.

One side is used to expose the problem of environmental organizations, media questioning, one side is sitting on the eucalyptus *** and official identity of scholars, experts, even if these environmental organizations, media questioning the existence of a lack of field research, scientific falsification of the attitude or even just a point of view, the people's heart of the balance also naturally inclined to the non- *** side. But ultimately, the "Greenpeace" organization's report, or the public's awareness, in the civil society organizations, the media's continuous discourse, the original review of human behavior, blamed on the existence of natural species.

Botanical culture

Eucalyptus is the collective name for plants of the genus Eucalyptus in the family Myrtaceae, probably originating at the end of the Cretaceous period, as there were already species with oblique sequential veins in the Eocene and early Miocene, and its primitive type was characterized by Mesozoic tectonics, which evolved mainly in Australia. Conforming to the changes in geological history, it also depends on its adaptation to dry, arid and semi-arid conditions, with a predominantly arid lineage, as well as Mesozoic and ice-loving lineages.

The adaptation of eucalyptus to arid conditions led to the formation of a series of morphological and anatomical structures. One of the earliest types of adaptation is the formation of gums, downy hairs or bristles on the leaves, but when drought is intensified, this protection is not very effective, so that, with a few exceptions, it is retained only during the young development of the plant, and later stages are the formation of a waxy epidermis. Eucalypts growing in mountainous and arid areas have a blue-gray wax layer on young and mature leaves, on branches, and sometimes on the trunk. By the modern stage of development, the cuticle of eucalyptus is thickened to facilitate its safest adaptation to dry conditions. It should be noted that all of the regenerative traits of eucalypts have developed from mesophytic evolutionary lineages.

Various species in the wet areas of northern Australia, and many trees in the wet coastal areas of the southeast and Tasmania and in the wet mountains should be classified in the mesophytic lineage. The ice-loving evolutionary lineage is an evolutionary lineage adapted to the cold ecology of the high mountains, which includes a number of species growing in the central dry regions of Australia, a region where survival conditions are characterized by dramatic diurnal temperature changes, often with high temperatures during the day (hot) and low temperatures at night (bitterly cold), and where eucalypts evolved in what is essentially a degradation, with an evolutionary program of trees-subtrees ­-small trees- Shrubs.

In 1982, the Chinese Academy of Sciences, Tibetan Plateau Comprehensive Expedition Team of ancient plant specialty group in the western region of Sichuan Province, altitude of 3700m, Litang County, the late beginning of the New Century stratigraphy, collected more than 40 Eucalyptus fossil plant specimens, these fossils have Eucalyptus leaf imprints of fossilized fossils, and fossilized fruits and flower buds. The fossils were initially identified as Eucalyptus thermorhynchus, a eucalyptus similar to the domestic eucalyptus and Eucalyptus terrestris.

More than ten years ago, in Tibet, Rikaze area and Jinggangdishan also found fossils of narrow-leaved eucalyptus. From the phytogeographic point of view, it can be conceived that in the late Eocene, four or five hundred million years ago, western Sichuan and Tibet distributed a large number of eucalyptus plants in broad-leaved evergreen forests, at that time, the climate in the above areas is warm and dry, very suitable for eucalyptus growth. Later, about millions of years ago, the strong Himalayan orogenic movement, so that the crust of western Sichuan and Tibet uplifted, eucalyptus plants are not adapted to the cold climate and disappeared, eucalyptus suitable for the gradual southward movement, through Malaysia to Oceania, to the present day, Australia has become the main distribution center of eucalyptus plants.

The fossils found in the late Eocene strata of China are about 10 million years older than the earliest recorded fossils of the same eucalypts found in the Eocene strata of Australia. This casts doubt on the long-held belief that eucalyptus plants originated in Australia. It is of great value in academic research, providing a basis for establishing geological ages and studying paleogeography, paleovegetation and paleoclimate.