Scientific name: Chimonobambusa bambusa. Xiaozhu. Underground stems are uniaxial or compound. The internodes are short, generally less than 20 cm, the lower internodes are cylindrical or slightly square, the branches are flat on one side, often with shallow grooves, and at least several nodes at the base each have a circle of conical short thorns transformed by aerial roots; The bud of the stalk is usually conical, and when it is drawn long, it adheres to the main stalk. 3. Branches are branched or multi-branched, and the branches are obviously ridged. Culm sheaths caducous or persistent; Wrinkleless ear; The flap degenerates into a small triangle or cone. Leaf blade lanceolate, small transverse veins clear. Spikelets usually grow singly or clandestinely on each node of the flower branch, often purple, containing several small flowers, sessile or terminal spikelets, with the internode of the flower branch as the spikelet stalk; Spikelet rachis articulate; Glumes 1 ~ 3 pieces, gradually increasing, with several veins; The top of lemma is sharp and has several veins; Palea slightly shorter than lemma, with 2 ridges, hairless, 3 pieces of pulp, membranous; 3 stamens; Ovary nan is round, glabrous, style 1, extremely short, stigma 2, pinnate. The fruit is oval with a thick peel. (See photo) There are about 30 species of this genus, which are produced in Asia and scattered in Japan, India, Myanmar, Vietnam and other countries. The mountainous area in southwest China is the distribution center of this genus, with about 18 species. In addition, Shaanxi, Hubei, Hunan, Jiangxi, Zhejiang, Guangxi and Fujian are also scattered. This genus is a subtropical mountain bamboo species, which is tolerant to shade and likes humidity, and naturally distributed in the mountainous evergreen broad-leaved forest area at an altitude of 800 ~ 2200 meters. It is common on both sides of canyons or exists as a lower wood layer in forests. There are common bamboos in southwest mountainous areas, such as Bambusa kaempferi, Bambusa spinosa, Bambusa spinosa and Bambusa Jinfo. Cold bamboo and square bamboo are produced in Fujian and Zhejiang provinces in the southeast. This genus requires cool and humid climate conditions and well-drained mountain forest soil, so it grows best in sparse forests; It is difficult to grow in hot areas, mountains and arid areas. Chimonobambusa bambusa is a famous bamboo for autumn harvest, which can be eaten fresh or made into dried bamboo shoots. The polished rod is smooth and tough, and can be used to make walking sticks and craft supplies. In addition, Chimonobambusa bambusa is also a popular ornamental bamboo, because it has a peculiar rod shape, such as thorns at nodes and slightly square culms.
Bamboo windbreak and sand fixation forest
(windbreak and sand fixation forest)
(high) according to
Forests built to prevent sandstorms and control desertification. Through the construction of windbreak and sand fixation forest, the vicious circle caused by natural and historical changes will be transformed into a virtuous circle. The protection system engineering, which consists of controlling quicksand, establishing oasis protection system and protecting and managing natural vegetation, not only plays a dual role in protecting social facilities and natural environment, but also is an important means to transform low-yield ecosystem into high-yield ecosystem.
The area of desert in the world is about 12 ~ 15% of the total land area, which can be divided into low-latitude tropical desert and mid-latitude temperate desert. The precipitation is below 250 mm, and the desert in China mainly belongs to the latter. The total area of northern desert, Gobi and desertified land is 6,543,800 square kilometers. Among them, desert (sandy desert) and sandy land account for 55.6%, and Gobi (gravel desert) accounts for 44.4%. Desert and Gobi are mainly distributed in the west of Helan Mountain and Wushaoling Mountain in arid areas, while 80% of the desertified land is distributed in the desert grassland and steppe belt in semi-arid areas, and the rest is distributed in the desert belt in arid areas.
9 Hainan coconut grove
Ding Keren
10 natural coniferous forest in Taiwan Province province
Provided by Li Peng.
1 1 ancient Chinese pine in the university hall
Li Peng
12 ancient tree of Pinus bungeana in Beijing Forbidden City
Li Peng
13 Taiwan Province Shenmu-Castanopsis kawakamii
Ding Keren contributed
14 Shandong Confucius Temple Cooper
Li Peng
15 Ancient Sophora japonica in Beijing Jietai Temple
Li Peng
16 Ancient Ficus mandshurica in Yangshuo, Guangxi
Li Peng
17 Ancient Ginkgo biloba in Shaolin Temple
Chungen Liu
18 Ancient Yushu in Dunhuang County, Jiangsu Province
Ding Keren
19 ancient camphor tree in Shangyu County, Zhejiang Province
Ding Keren
Left-handed willow in Lhasa
Wang suddenly said
2 1 Chinese Academy of Forestry Science
Li Peng
22 Nanjing Forestry University Campus
Ma Ji You
23 Beijing Forestry University students do surveying practice
Zhao Zongyuan
Students of Northeast Forestry University are doing logging practice.
Jiang
25 China's ancient forestry works
Xu jijia
Desert is a natural landscape formed by the interaction of dry climate, wind and sand in ancient lakes during geological history. In the hinterland of the desert, there are large sand dunes with large scale, systematic morphology and rules, which keep a dynamic balance with the wind. The forms of sand dunes are mainly crescent, linear, pyramid, parabolic, dome and their derivatives. The expansion and spread of the desert form temporary sand dune characteristics, but they will be adjusted by a storm. This sand dune migrates at the speed of 1 ~ 2m, 5 ~ 10m or faster every year, which is harmful to oases, traffic and industrial facilities. Gobi is Quaternary alluvium-alluvium is composed of gravel, crushed stone and sand, and the ground is flat. Formed by denudation-eluvial deposit-slope deposit, the ground does not fluctuate, the bedrock is exposed, the gravel layer is thin, the mountain is almost eroded, the valleys are severely divided, and there is no river. Gobi has large particles on the ground and is difficult to be blown away by the wind. Only the sand in Gobi will produce wind-blown sand flow hazard under the action of wind, but it is much less harmful than the desert. Desertification is due to natural and historical factors, river changes, desert expansion, and ancient oases and castles are swallowed up by quicksand, resulting in desert-like landscapes that cannot be restored by nature. Desertification refers to the ecological degradation caused by man-made deforestation and grass planting in arid areas, and the sand in the original fixed sand land generally moves again, resulting in the large-scale distribution of sand dunes on the ground.
Development history
Russia built a railway crossing Karakum Desert in 1895, and discussed the control measures of quicksand to prevent sand damage. 19 12 established Lebede Czech Desert Research Station to study the dual projects of mechanical sand barrier and plant sand fixation. Since 1950s, Iran, Libya, Algeria, Egypt, Saudi Arabia, India, Southwest Africa and other countries have successively carried out afforestation and green belt projects to rebuild vegetation. Since 1960s, chemical mulch has been used to fix sand and protect important facilities and foundations from sand damage. One chemical sand-fixing agent is water-soluble resin emulsion, and the other is liquid polymer. Using this material to cement quicksand to fix it requires spraying 3785 liters per hectare, and the validity period is six months to three years. It is far less economical and effective than using plant materials as sand-fixing mulch.
Around the early Qing Dynasty in China, farmers in Hexi Corridor of Gansu Province began to "insert wind walls" to intercept quicksand and "protect Chai Wan" to protect natural vegetation from desertification. Villages made village rules and regulations to protect Chai Wan. Since the early 1950s, desertification control and afforestation have been carried out on a large scale. First, the backbone forest belt will be built in the northeast and west of semi-arid areas, and then1.835km windbreak and sand fixation forest belt will be built in Inner Mongolia, northern Shaanxi, Hexi Corridor of Gansu and Ningxia. At the same time, the artificial oasis in Xinjiang desert reclamation area has built a windbreak forest network on a large scale, making the shelterbelt in reclamation area account for 4.8 ~ 6% of the cultivated land area, with a large coverage rate of 12.8%. In addition, on the harmful flowing sand dunes outside the sand-fixing windbreak forest, sand barriers are initially supplemented, and shrubs such as Haloxylon ammodendron, Calligonum Calligonum and flower sticks are planted to fix sand and control the spread of quicksand. On semi-fixed sand dunes, the plant coverage can be restored to 50% after 3-5 years. By the end of 1977, the afforestation and preservation area in the sandstorm area was10.9 million hectares. 1978, China decided to build the "Three North" shelterbelt system project. The first phase of the project to1985,226 sandstorm counties has been completed as planned. China's first baotou-lanzhou railway crossing the desert, from Lanzhou to Yinchuan, crossed the Tengger Desert six times, including the section from Yingshui Bridge to Mengjiawan 16 km, all of which are tall lattice dunes. Since the sand dunes were covered with checkered grass barriers and shrubs and perennial grasses were planted to control sand, the normal operation of the trains has been basically guaranteed since the opening of traffic on August 65,438+0,0958. Since then, Lanzhou-Xinjiang, Jining-Erlian, Gan Tang-Wuwei, Uda-Jilantai (Lan Xin, Jiji, Ganwu and Wuji) and other trunk lines and feeder lines have been built one after another. In order to keep the railway unblocked, a large number of sand prevention projects have been carried out. The prevention and control of highway sand damage in sandy areas in China are as follows: firstly, sand transportation is used to prevent sand from burying the road surface; The other is to use the comprehensive measures of setting up mechanical sand barriers to protect roads, transporting sand by wind and fixing sand by plants to prevent sand from pressing roads.
Sand control measures
The principles of our national defense and sand control are: comprehensive planning and comprehensive management; Combine pest control with profit improvement; Combination of transformation and utilization; According to local conditions, fortify and prevent harm; Combination of biological measures and engineering measures; A large number of afforestation and grass planting are combined with the protection and consolidation of existing vegetation. There are several ways to do this:
Control quicksand
The hazards of sandstorms are all caused by the erosion, transportation and accumulation of sand particles by airflow. According to the law of wind-blown sand movement, in order to cause accumulation and sand stagnation, it is necessary to reduce the wind speed, make the airflow sediment concentration in a supersaturated state, stabilize the sand surface, and weaken the bearing capacity of wind speed to sand particles. In order to cause erosion, sand guide or non-accumulation transportation, it is necessary to increase the wind speed or cut off the supply of sand sources, so that the sediment content of the air flow is in an unsaturated state and the sand transport capacity of the air flow is increased. Therefore, control measures include engineering sand prevention, plant sand prevention or a combination of the two. ① Engineering sand control: Mechanical sand barriers (or wind barriers) are widely used. That is, using firewood, clay, branches, slats, pebbles and other materials, sand dunes are fully tiled or banded, or inserted vertically in rows. Wind-driven sand pulling in engineering measures is used to remove sand burial hazards in highway protection sections. Usually, the wind gathering plate is set to change the conveying direction of quicksand, or the lower inlet of the wind gathering plate is used to strengthen the downward wind guide, which causes the change of flow field structure near the road surface and the increase of airflow speed, so that quicksand does not accumulate on the road surface. In areas with water conservancy conditions, in order to eliminate sand damage, it is also an engineering measure to use hydraulic sand to build fields, repair canals and build dams. This has rich experience in the sand area of northern Shaanxi, China. ② Plant sand control: it is an economic, effective and lasting measure to control quicksand. The key to the success of afforestation and grass planting in mobile dunes lies in the choice of tree species: desert, semi-desert and grassland are in three climatic zones, and the properties of underground objects in the same climatic zone are different. Therefore, native trees, shrubs and grass seeds suitable for local natural conditions and production development should be selected, and excellent exotic trees, shrubs and grass seeds that have been successfully introduced can also be adopted. It is important to choose xerophytes. Trees and shrubs suitable for desertification control and afforestation in China are: Artemisia rupestris, Populus tomentosa, Lespedeza, Caragana microphylla, Salix psammophila, Elm, Populus euphratica and Pinus sylvestris var. mongolica. Mongolia and so on. ; There are Artemisia ordosica, Artemisia ordosica, Caragana korshinskii, Populus tomentosa, Astragalus membranaceus, Salix psammophila, Salix matsudana, Populus simonii and Populus euphratica in semi-desert areas. There are Haloxylon ammodendron, Calligonum mongolicum, Caragana korshinskii, flower stick, Tamarix chinensis, Nitraria tangutorum, Salix matsudana, Populus davidiana, Populus alba, Populus Xinjiang, Populus euphratica and Elaeagnus angustifolia in the desert area. But the choice of tree species needs irrigation. Generally speaking, planting seedlings for afforestation is more reliable. Afforestation requires planting (pressing) strips (drying) in areas with good water and soil conditions, while direct seeding afforestation can usually be carried out in areas with more rainfall.
Establishing a windbreak and sand fixation system in oasis
Including setting up various engineering measures on the flowing sand dunes outside the oasis, mainly blocking the tuyere and blocking the sand source at the source of quicksand invading the oasis; In the front of the desert that invaded the oasis, a wide sand-sealing and grass-planting belt was established to stop sand and reduce the sediment content in the surface wind-blown sand flow, and prevent the invasion of the oasis by foreign quicksand; Promote the natural restoration of vegetation through zoning and closure, replant grass and shrubs with precipitation and irrigation through manual intervention, and build green belts; Building windbreak and sand-blocking forest belts on the edge of oasis farmland, which are composed of single-belt or double-belt forest belts, facing the desert and backing the oasis, reducing wind speed and settling suspended sand in airflow; Establish criss-crossing farmland shelterbelt network in oasis to adjust the surface microclimate. This layered fortification, because different forms of windbreak and sand fixation are interrelated, can produce comprehensive control benefits and maintain the ecological balance of oasis.
Closing sand for afforestation
Land desertification has both natural factors and human factors. In order to prevent and control desertification, besides planting grass and planting trees, measures must be taken to protect natural jungles and shrubs. For the area adjacent to the oasis, according to the situation of sand source, first delimit the scope, plan the fence width (generally 500 ~ 1000m), gradually restore vegetation and form a green barrier. For relatively stable shrubs in the desert, such as Haloxylon ammodendron forest, Tamarix ramosissima, Baiti sand pile, etc. We should focus on management and protection measures, partition enclosure and rotational grazing, so as to create conditions for shrubs to bear fruit and renew natural seeds. Desert valley forests, such as Populus euphratica forest, Populus euphratica forest, Populus alba forest, Elaeagnus angustifolia forest, etc. Due to the change of river course and human influence, the area of forest land is reduced, the area of desertification is increased and the role of natural barrier is reduced. In order to protect and expand the valley forest, we should adopt segmented management, rationally allocate water resources, and promote the regeneration of natural seeds and natural shoots.
With the development of arid areas and population growth, economic activities and disastrous climatic factors have more and more influence on nature. Nowadays, the problem of desertification is spreading to Asia, Africa, Australia, the United States and the European continent to varying degrees. According to the estimation of the United Nations Conference on Desertification, 50,000-70,000 square kilometers of land are degraded into desertification every year. Therefore, how to rationally develop water, soil and plant resources in arid areas and obtain benefits, and how to protect the environment and take reasonable measures are a major issue in the future. In the past, the focus was on preventing harm, but in the future, we must also consider the transformation, management and protection of renewable resources. That is to say, from both macro and micro aspects, zoning plans are made according to different types, prevention and control demonstrations are established in each district, and the dynamic changes of deserts and grasslands are monitored by remote sensing technology to arrange for the restoration of ecological balance.
philology
Editorial Board of Desertification Control and Afforestation: Desertification Control and Afforestation, China Forestry Press, 1984.