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Home > Industry Information > "North China Larch Pine Fast-growing and High-yielding Forest Cultivation Technique"

"North China Larch Pine Fast-growing and High-yielding Forest Cultivation Technique"

2021-04-25

one. Afforestation Effect of Seedlings Cultivated by Seeds of Mother Trees

In the young plantations of Larix principis-rupprechtii, good stands were selected, and they were reclaimed and reworked. The management measures such as watering, fertilizing and pruning were adopted to establish the Larix principis-rupprechtii mother trees. A certain amount of genetic gain (Table 4-4).

Table 4-4 Afforestation effect of seedling seedlings of Larix principis-rupprechtii

Forest species

Age (a)

Breast diameter (cm)

Tree height (m)

Volume (m3)

Mother trees seed stands

10

5.70

5.17

0.0081

Ordinary seed stands

10

5.40

5.07

0.0071

Mother tree gain %

/

5.56

1.97

14.08

After the afforestation of seedlings and common seedlings of Larix principis-rupprechtii mother forest in the Longjiangshan Forest Farm of Longtoushan Forest Farm, the DBH, tree height and volume were respectively 5.56%, 1.97%, and 14.08%.

two. Afforestation Effect of Seedlings Cultivated by Seed Garden Seeds

The orchard is an excellent seed production base established by artificially selecting excellent trees and using clones or offspring as their materials. The seeds and seedlings produced by them have excellent genetic quality and high viability.

Compared with ordinary forests, the diameter, height, and volume of DBH increased by 8.74%, 13.01%, and 27.06%, respectively (Table 4-5).

Table 4-5 Afforestation effect of Larch of superior trees of North China

category

Age (a)

Breast diameter (cm)

Tree height (m)

Volume (m3)

Excellent Tree Substitute Forest

15

10.20

10.16

0.0493

Control

15

9.38

8.99

0.0388

Sub-generation forest gain%

/

8.74

13.01

27.06

three. Asexual propagation of afforestation

Forest cuttings and nursery is one of the main asexual breeding methods. Using full-light spray cutting propagation techniques and equipment, utilizing the physiological and genetic characteristics of cuttings of Larix principis-rupprechtii, through the synthesis and physiological effects of endogenous auxin and other substances, the formation of adventitious roots is promoted by the effect of endogenous substances, making cuttings difficult to root. Larix principis-rupprechtii reproduces easily. The method of seedling raising has the advantages of simple procedure, quick effect, stable economic traits and maximum genetic gain. Vigorously developing asexual propagation seedlings of Larix principis-rupprechtii is a development direction for the construction of fast-growing and high-yield larch forests.

The Hebei Provincial Academy of Forestry studied the use of full-light spray cutting equipment at Longtoushan Forest Farm to cultivate 1.5-year-old mixed cutting seedlings, compared with the same-origin (mother-tree seed) 2-year-old seedling afforestation experiments, after afforestation for 6 years, The full height and the DBH growth of the 1.5a seedlings and 2a seedlings were basically the same, and the shoot growth was also similar, indicating that the cutting seedlings can maintain the excellent growth characteristics of the female parent (Table 4-6).

Table 4-6 Comparison of young tree growth between cutting and seedlings

Unit: M

Kinds of seedlings

Base path

Breast diameter

Plant height

New shooter

Cutlery Miao Lin

2.81

0.91

196.6

50.0

Miao Lin

3.01

0.96

202.0

51.5

Section 5 Afforestation Season and Methods

To establish a fast-growing and high-yield forest of Larix principis-rupprechtii, it is necessary to study the afforestation season and methods. With the appropriate density, fine soil preparation, good seeds and strong seedlings, such as afforestation season and improper method selection, it will also affect the survival rate of afforestation and the growth of forest trees. Therefore, to establish a fast-growing and high-yield forest of North China larch, it is necessary to determine a suitable afforestation season, but also to select appropriate afforestation methods, coupled with intensive management, so as to achieve the purpose of rapid growth and high yield, and strive to provide the highest quality wood in the shortest time.

First, afforestation season

To determine the appropriate afforestation season, comprehensive consideration must be given based on the biological, ecological characteristics, climatic conditions, soil conditions, and socioeconomic factors of the afforestation tree species. Based on the above factors, combined with years of research, it is advisable to establish a fast-growing and high-yield forest of Larix principis-rupprechtii in spring and autumn.

1. In the spring thaw period of spring afforestation, the soil moisture content is relatively high and the soil moisture is good, which is a suitable season for afforestation. In the spring, the soil began to thaw, and the thawing was observed daily before wormwood turned green. When the thawing depth reached 20CM or more, the plants were planted, the first slope was followed by the shady slope, and the first slope was followed by the hillside afforestation. At the same time, during the spring afforestation, the above-ground parts of the seedlings are still in a dormant state. After the afforestation, when the seedlings begin to grow, the roots grow. When the seedlings grow, the upper part of the seedlings germinates and leaves are placed, so the survival rate of afforestation is relatively high. Larch planting in the spring must master the soil thawing and top soil afforestation prior to seedling sprouting, and the planting should be completed before the seedlings are planted. However, there are also disadvantageous conditions for afforestation in the spring. First, the spring temperature rises quickly and the afforestation time is short. The afforestation time overlaps with the spring cultivation time, resulting in insufficient labor force. Therefore, reasonable arrangements must be made to organize the labor force and prepare the planting tools as soon as possible so as to prevent surprise operations. The construction of fast-growing and high-yield forests requires strict and adherence to professional team afforestation.

2. Afforestation in autumn

The gradual fall in temperature in the autumn, the more stable and stable soil moisture, is a better season for afforestation. If the spring drought, severe wind, it should be selected in the autumn afforestation. The seedlings in the fall are lifted after being defoliated and transported directly to the afforestation site. After the temporary planting, they are planted day after day until the end of freezing. During afforestation in autumn, the defoliation of seedlings enters the dormant period, and the evaporation of the above-ground part drops to a very low level. The physiological activity of the seedling root system in the soil is still continuing, which is very favorable for afforestation. Afforestation takes a long time in the fall and it is easy for organizations to initiate labor. In the autumn afforestation, the roots of the late spring and early spring temperatures rise and activity can be restored, and the water absorption capacity can be restored earlier. When the late spring drought season arrives, the trees have returned to normal growth state, thereby enhancing the resistance and increasing the survival rate. However, autumn afforestation also has a negative side. Winter seedlings are vulnerable to damage on the afforestation land, and they are easy to dry shoots. The spring planting seedlings have adapted to the microclimate of the forested land and lived in a season with increased adaptability. At the same time, if the afforestation is too late, the soil freezes. It is not easy to step on solid materials, and it is easy to cause seedlings to die due to loose soil. In case of spring drought and strong winds, seedlings are more likely to die. Full consideration should be given to favorable and unfavorable factors. In determining the timing of afforestation, we can seek advantages and avoid disadvantages, or take preventive measures as soon as possible.

3. A reasonable arrangement of afforestation season for afforestation season will help guarantee the quality of afforestation, improve the survival rate of afforestation, and successfully establish one afforestation. Generally, the autumn sensation is better, and it can be arranged in appropriate ways to prevent drought in the spring of the next year, or the prevalence of hot dry wind in the early spring is not conducive to afforestation. If the autumn forestry land is poor and the soil dry soil layer thickness is more than 5CM, it is impossible to force the afforestation to be postponed until spring. According to the conditions of winter snowfall and precipitation in spring, according to the soil moisture content of the planting land. If soil moisture is good in spring, the general survival rate is higher than that in autumn. If the spring drought or severe drought, afforestation points dry soil layer thickness of 5CM or more, you should be careful, not stubborn or blind afforestation. Because the main factor in the survival of afforestation seedlings is the ability of the roots to absorb water and nutrients from the soil after the seedlings are brought into contact with the soil. The most fundamental problem is that the effective moisture content of the injured roots buried in the soil significantly exceeds the wilting coefficient of the seedlings. . Therefore, it is said that general planting is qualified, that living can not live on water, and living well is not good. In short, careful consideration should be given to the arrangement of the afforestation season, especially for afforestation on barren hills and barren lands. The amount of tasks for large precipitation years and the number of tasks for drought years can be reduced or eliminated.

Second, afforestation methods

Afforestation methods are divided into three afforestation methods: sowing, seedlings planting and division according to the different materials used for afforestation. To build a high-yield larch plantation in North China, afforestation must be used.

(A) The advantages of planting seedlings and afforestation

Seedlings and afforestation can be applied to a variety of site conditions. Young trees grow faster in the early stages, which can shorten the forest cultivation cycle.

(II) Technical requirements for seedlings and afforestation

1, seedlings specifications: selection of two-year seedlings seedlings first grade seedlings, seedlings normal color. Requires ground diameter 0.5CM or more, seedling height greater than 45CM, height-to-diameter ratio less than 90, main root length 20CM, greater than 5M long lateral roots 12 or more, seedlings with good lignification, full head buds, no pests and mechanical damage, no lifting process Lost water phenomenon. And the thickness of the same batch of seedlings is highly uniform, with no unevenness.

2. Seedlings handling and protection Seedlings have been carefully managed in the nursery. However, the environmental conditions of the reforestation sites have changed greatly and it is impossible to control them artificially. The seedlings will face an environment without artificial irrigation and protection. Drought, high temperature, low temperature, vegetation competition, and animal destruction may occur at any time. Therefore, it is very important to provide a good moisturizing environment for the seedlings after they are transported to the forest land and during the planting process.

(1) Seedling transport: The best seedling transportation environment is to maintain the seedlings under similar storage conditions, ie, temperature of 0 to 3°C and relative humidity of 90% to 95%. During the transportation process, the packaging materials should be determined according to the transport distance. Short-distance transportation can be packaged with straw curtains, and the transportation process should be checked frequently. If the seedlings are found to be dry, they should be watered at any time. For long-distance transportation, good moisture-retaining materials, such as KP Bags, must be used. The transport vehicle must also be sheltered by a canvas shelter. Seedlings are not allowed to be exposed to the sun and wind, and they must not be transported without any packaging or bare root.

(2) Protection of seedlings after they are transported to the afforestation land: After the seedlings are transported to the afforestation site, they should be flat, leeward, shade-neutral, and water-rich. The seedlings should be planted in the soil in time, and the root system should be fully in contact with the soil. Watering.

(3) Protection of seedlings during planting: Pay attention to seedling moisturizing during planting. Before seedlings are loaded into the seedling barrels, moisten with mud or moisturizer, so that bare roots of the seedlings are not exposed to the air. After moisturizing into the seedling barrel, planting a strain to take one strain is extremely beneficial to the protection of seedling vitality. When taking seedlings, be careful not to separate the seedlings vigorously, because the roots of the seedlings are tangled together and the seedlings are forced to separate, which will injure the seedlings of the seedlings and adversely affect the survival of the seedlings.

In short, we must conscientiously strengthen the protection measures for seedlings in all aspects of afforestation so as to avoid the omission of a certain link and affect the entire afforestation project.

3, seedlings storage: If the fall after the start of the plan, planting in the spring, the seedlings must be winter planted or cellar. L. chinensis has good cellaring effect. At the same time, it actively increased the proportion of spring seedlings and spring afforestation to reduce intermediate links, reduce costs, increase the degree of lignification of seedlings, and improve the quality and survival rate of seedlings.

(1) Over-winter leave: Autumn seedlings Afforestation in the spring is required for wintering. In autumn, sandy lands with good drainage, leeward sunlight, near water source, and no livestock hazards are to be opened east to west. The seedlings shall be arranged in rows so that the seedlings are perpendicular to the ground, and the roots will be prevented from bending, covering the earth to the original earth and India, and then The soil is irrigated and the seedlings and the soil are fully combined by water pressure. During the winter, it was covered with straw and windproof. In the spring, the wind was covered with straw and shade, and the germination period of seedlings was delayed. The freezing period of the soil in the afforestation land was the same as that of the soil in the planting ground. Before wintering, the larch seedlings must be cleaned to prevent mildew in spring seedlings and to prevent rat damage.

(2) Cellar: The purpose of winter larch planting seedlings in North China is to prevent the physiological drought of seedlings caused by strong winds in winter and spring, to prevent premature sprouting of seedlings in early spring, and to control the physiological activities of seedlings, so as to make it consistent with the soil conditions of the afforestation fields. Measures. Select the lee, low groundwater level, and convenient management of the land to dig deep into the soil before harvesting, depth 1.5M, upper mouth width 2M, lower base width 1.7-1.8M (2 times the height of seedlings, the middle of the trail 30 ~ 50CM) seedling pit The length depends on the amount of seedlings, and is calculated for 20,000 seedlings per extension. When the cellar temperature stabilizes at 0~3°C, enter the cellar, temporarily dislocate the seedlings of L. principis-rupprechtii and remove the needles, then the roots will be watered, and the roots will face the cellar wall (from 3 to 5 cm from the cellar wall). Head towards the middle trail. Before laying seedlings, wet sand 5 to 10 cm in the bottom of the kiln, and then put the seedlings in bundles. Place a layer of seedlings on each side of the roots to flatten 3 to 5 CM thick wet sand on the side of the roots. There must be no clay in the wet sand to prevent air leakage. Poor and hot mold, while the wet sand requires fine uniform, not allowed to have large grain gravel, to prevent mechanical damage and dehydration seedlings. This layer by layer, the seedlings can be used to flatten the straw slightly to keep the seedlings loose and ventilate, and it is always placed until 40cm from the pit. When the wet sand is used, the seedlings are buried in a strict level with the pit, and the moisture content of the wet sand is 60. % is appropriate (that is, when the group is released, it is scattered). In order to prevent wind and sun, you can pad the 20CM earthwork or masonry blocks along the pits, and use the caskets to bear them. Cover the straw or straws to cover the wind and prevent the drying. Wait until the big freeze comes and the river freezing season. Leave a 40×40CM vent hole every one meter of the cellar cover, plug it with straw, and seal it with straw and pre-prepared loess. Always keep the temperature in the pit below 0 ̊C. In the spring of the following year, the temperature in the pit was adjusted by vents to make it consistent with the thawing time of the plantation, and the larch sprouts in the pit were controlled. In addition, the seedlings must be inspected after entering the cellar. It is found that the temperature is too high to shade and the air in the cellar must be sprayed with water. The high temperature inside the pit before the spring planting can increase the temperature of the cover and cool the ice in the pit to delay the sprouting of the seedlings. Check whether there is any rodent damage in the cellar, take preventive measures, and gradually open the cellar door before afforestation, so that the temperature and humidity inside the cellar should not be changed drastically.

4, planting methods and techniques

(1) Planting methods The seedlings used for constructing the fast-growing and high-yielding forest of Larix principis-rupprechtii are generally 2 years old sowing seedlings with a small root system, and the conditions for afforestation are generally superior. The soil layer is thick, fertile and loose. According to the practice of afforestation for many years, the seedlings are used. The method of planting in a narrow slot is good. This method has the advantages of rapid afforestation, high work efficiency, and high survival rate of afforestation.

(2) Planting technical points

First, seedling processing technology. Selection of seedlings, cutting roots: Generally, after seedling or winter storage, the seedlings have more mud, and before transplanting, the roots of the seedlings should be washed with running water or clean water first, and then the roots should be poor, without apical buds, and the main machinery must be damaged. The seedlings that are not suitable for afforestation are discarded, and then the roots of the qualified seedlings are pruned. Pruning: Mainly cut off long horizontal roots, main roots, mechanically damaged roots, moldy or dry lateral roots, and expose new cuts at the sheared position to facilitate the rapid recovery of root trauma and absorption functions, and to divide the callus as soon as possible. Root system.

Pharmacy treatment: For larch afforestation, it is better to use axillary root powder and mycorrhizal afforestation techniques to increase the survival rate and promote the growth of saplings. Rooting powder is a broad-spectrum and efficient rooting accelerant that promotes root recovery and the germination of new roots; mycorrhizal agents (which can also be inoculated with pinewood soil with mycorrhizal agents) can improve stress resistance and toxic substance contamination in trees. Enhance and induce tree disease resistance, increase soil activity, improve soil physical and chemical properties, increase root absorption area, and promote the development of plant communities in favor of the balance of the forest ecosystem. These two technologies are effective for improving afforestation quality and are separately described in the following paragraphs (slightly here). Seedlings root mud is also a good method of moisturizing the root system. The method is: using yellow soil and mountain brown soil and mud into a thick and moderate mud, the root diameter of the seedlings below the diameter of all immersed, so that the root layer of a layer of mud, in order to facilitate moisture. It is also possible to use water retaining agent and appropriate amount of water to form a gel root. The effect is also very good.

Second, planting technology. Planting technology mainly refers to the planting depth, root elongation, whether it is compacted and compacted, and whether the location is reasonable or not. Under normal circumstances, the soil conditions for the establishment of high-yield forests are relatively good, and the soil is fertile and moist. According to the characteristics of Larix principis-rupprechtii, planting depth can be generally equal to the ground diameter of the seedlings and the ground. In particular, the wet soil in the soil must not be deeply planted. , but slightly shallower. The opening depth of the seedling shooter must reach 20 cm or more, and the gap is required to be large enough so that the seedlings can be sent deeper and shallower, so that the root system can be stretched to avoid “rooting”. It is required to use force when squeezing from the side to prevent the root from getting wind, but do not use excessive force, otherwise the seedlings will be dug out. In addition, the seedlings are required to stand upright and lie in the hole and slightly on the side of the hill.

In short, the planting process should pay attention to the depth of shallow mention, shallow depth suitable for compaction, stepping solid, anti-vegetation planting too deep. The seedlings are perpendicular to the ground plane and can withstand the slight lifting of the fingers to prevent the root from curling and deforming. Planting seedlings and afforestation should not be rooted, because the roots hindering the transport of nutrients not only affect survival, but also have poor growth after survival. Judging from the anatomy of the dead seedlings of Larix principis-rupprechtii in the Mengwei Forest Management Bureau for many years, most of the deaths of seedlings were caused by the planting of roots, too loose and too deep.

Third, rooting powder, moisturizer and mycorrhizal root axillary afforestation technology

1. Afforestation of rooting powder Afforestation of L. principis-rupprechtii Afforestation with rooting powder can promote root wound healing and fibrous root growth of seedlings, thereby effectively increasing the survival rate of afforestation and increasing the biomass growth of seedlings. In the Longyingshan Forest Farm investigation area, the ABT rooting powder No. 3 was used to treat 2-year-old primary seedlings of Larix principis-rupprechtii for 4 hours, and a mud afforestation test was conducted. The test results are as follows (4-7).

Table 4-7 Effect of Afforestation of Larix principis-rupprechtii Afforestation

Rooting Powder Concentration Survival Rate (%) Arc Sine Transformation Value Seedling Biomass (g) Ground Diameter (CM)

100μg/g 83.9 66.34 305.0 0.547

82.6 65.35 299.7 0.567

82.0 64.90 301.0 0.572

88.6 70.27 304.1 0.560

50 μg/g 91.7 73.26 356.5 0.650

91.8 73.36 403.0 0.667

91.8 73.36 387.0 0.647

95.9 78.32 396.6 0.620

25μg/g 83.8 66.27 485.0 0.660

82.5 65.27 456.2 0.657

89.5 71.09 466.5 0.650

88.2 69.91 463.2 0.640

Comparison 81.3 64.38 335.0 0.580

80.6 63.87 335.4 0.560

87.8 69.56 330.0 0.530

81.6 64.60 353.3 0.525

From the above test results, it was concluded that after soaking the roots of L. principis-rupprechtii with different concentrations of rooting powder, the survival rate of afforestation was higher than that of the control, with the highest concentration of 50 μg/g and the lowest concentration of 100 μg/g; 25 μg/g and 50 μg/g. g rooting powder treatment seedlings, can increase the biomass of seedlings, 25ug / g best, 100 μg / g seedlings, seedling biomass does not increase down, indicating that the concentration of rooting powder is too high, then have inhibitory effect on the growth and development of seedlings ; L. principis-rupprechtii with 50 μg / g rooting powder for planting seedlings is the best afforestation effect.

(1) Preparation of rooting powder: ABT rooting powder is a broad-spectrum and efficient rooting accelerant. ABT rooting powder series No. 1 ~ 5, need to dissolve with alcohol or cosolvent SHB. When used, first prepare a 1000 PPM stock solution and then dilute it to the desired concentration. ABT No. 6~10 is a newer, broader spectrum, and more efficient type of green plant growth regulator newly developed after ABT rooting powder No. 1 to No. 5. It features simpler use than No. 1 to No. 5. Convenient and soluble in water, it can be stored at room temperature for more than 2 years. When using this product, 1 g of rooting powder is directly dissolved with a small amount of distilled water, cold boiled water, or purified water, and diluted to the desired concentration. The required concentration is calculated with reference to the following formula: Kilograms of water added = [1 / desired concentration ()] 1000

Specific operation method:

1, 1 ~ 5 rooting powder, with alcohol 0.5K will be dissolved 1g rooting powder, plus 0.5K distilled water (or cold water) formulated as a 1000PPM stock solution. The concentration is 30 seconds for large speeds and 0.5 to 2 hours for low concentrations.

2,6 ~ 10 rooting powder without alcohol, directly with distilled water or cold water 1K dissolved, formulated into 1000PPM stock solution. When used, dilute to the desired concentration according to the above formula. In the fast-growing and high-yield forest of North China larch, 50PPM was used for soaking the roots, and the roots were immersed for 0.5-2 hours. The 2nd-year seedlings of Larix principis-rupprechtii were treated for 2500-3000 plants per g of rooting powder. When reaching the number of seedlings to be treated, the original liquid must be removed, and the rooting powder must be re-treated to the required concentration. The use of the original liquid must not be used for treatment.

(2) Digging the root pond: Plant the amount of seedlings per day, dig the mouth wide 50CM, the bottom width 40CM, deep 30 ~ 40CM pool, the length can be determined according to the need to soak the seedlings. Use a plastic sheet to pave the pool to make a plastic cloth pool. According to the actual needs of production, first inject 1000PPM stock solution into the pool and add water to dilute to the required concentration. Commonly used concentration 25 ~ 50ppm, according to the proportion of 1000ppm into the pool solution, and fully stirred evenly, the liquid depth of 20CM or more. After washing the seedling roots with soil, selecting the seedlings and cutting the roots, the roots of the seedlings shall be immersed in the pool and soaked at the time required for the different rooting powder and its concentration.

2. Water-absorbing agent afforestation technology: The traditional afforestation technical measures of North China larch are bare root mud, temporary artificial planting, straw-curtain packaging and transportation, loading into seedling barrels and afforestation. The disadvantage of this method is that the seedlings have complicated processing procedures, serious waste of resources, and high cost. In 1990, Longtoushan Forest Farm chose cross-linked sodium polyacrylate SDL-600 (commonly known as water-absorbing agent) 200 to 400 times to root, 40*40M type plastic bag seedlings, shady laying 15 days after afforestation, the survival rate is as high as 88.5 %, (Table 4-8)

Table 4-7 Effect of Water Absorbent on Survival Rate of Afforestation

Water-absorbing agent survival rate of different seedlings during storage

Concentration 3d 8d 15d

200 times 88. 88.1 88.5 1. Apply water-absorbing agent to seedlings and leave without any treatment.

300 times 92. 86.7 83.5

400 times 88. 91.9 85.6 2. Mud seedlings, according to the routine, at any time spray moisturizing.

Comparison 93.3 91.9 85.6

From the above table, the survival rate of afforestation with 200-400 times water-absorbing agent is similar to that of the control. However, when the seedlings were planted for 15 days, the survival rate of the latter decreased greatly, indicating that the effect of the water-absorbing agent was changed and the effect was stable and reliable.

From the treatment of seedlings to the cost of planting, accounting for all expenditures included in the books, the cost of applying water absorbents was 49.3% less than the conventional method. Such as the general use of absorbent gel treatment of larch bare root seedlings, 10g can handle 200 to 350 or so, 1 ton water absorbent price is generally 15,000 yuan, 10gx water absorbent is only 0.15 yuan, the cost per plant is less than 1 cents, and the other social benefits To highlight this, taking the Longtoushan nursery as an example, the annual production of 5-6 million larch seedlings requires 100m3 of muddy soil. After the use of water-absorbing agent, the cultivated land of 0.1 mu can be protected each year, and 0.6 million K of straw material can be saved. 1 ton of fuel. On the other hand, in dry years or regions, planting roots with water-absorbing roots helps to maintain soil moisture near the roots of seedlings and increase the survival rate of afforestation. In addition, the use of water-absorbing agent root moisturizing, light weight, easy transport and artificial planting, reduce labor intensity, it should actively promote the use of water-absorbing agent root technology, and gradually reduce the use of muddy mud method.

3. Mycorrhizal root technology One-liter No. 1 mycorrhizal was diluted with 5K of water, and appropriate amount of yellow earth was added. The mixture was evenly mixed, then the roots of the appropriately pruned seedlings were immersed. After 5 seconds, afforestation was performed according to conventional afforestation methods. Pine forest soil slurry with mycorrhizal fungi can also be used. The practice of afforestation shows that the use of mycorrhizal roots has greatly promoted the growth of seedlings and sapling roots, formed relatively large root systems, accelerated the survival of seedlings and the growth of saplings, and greatly enhanced the resistance of seedlings, and should be vigorously promoted.

Section 6 Young Forest Care

After the afforestation to the closure of the young forest, a series of technical measures adopted for the forest land and young seedlings are collectively referred to as young forest tending. New young forests generally go through the process of restoring (sustaining seedlings), taking root, growing, and gradually entering fast-growing. This period is a key stage in the forest tree life, and it has a great relationship with the fast-growing and high-yield industries. At the same time, the forests at this stage have not yet been closed, the young forests are basically scattered, and the main contradiction of forests is the contradiction with the external environment. The main task of scientific management and intensive management at this stage is to create superior environmental conditions for young seedlings and young trees of Larix principis-rupprechtii, meet the requirements of young trees for water, fertilizer, gas, light and heat, and achieve a high survival rate. And the preservation rate makes it grow rapidly and lays a good foundation for fast growth, high yield and high quality. The content of intensive management in this stage is actually the content of young forest tending. For larch strong positive, not resistant to shade, shallow roots, fast-growing, hi moist, fertile, loose soil and other characteristics, mainly from the soil management, through the loose soil, Weeding, fertilizing, improving the physical and chemical properties of the soil, and eliminating the effects of weeds and shrubs on young trees. On the other hand, necessary suppression and adjustment of the forest itself, such as timely replanting, pruning and removing competition branches, etc., will be made to grow into forests quickly and healthily. In the young forest tending work, it must be timely and avoid injury.

(A), re-step

For Larch of North China Larch planted in autumn, the depth of soil defrosting is close to the root depth of the seedling before and after the spring of April of the following year. According to the soil and water conditions of the cavernous soil, the back slope beam slope, the first slope back slope, and the retrogradation of the slope are timely organized. The 10CM soil around the seedlings is compacted to eliminate the damage caused by different degrees of freezing in the winter, so that the seedling root system is in close contact with the soil, reducing ventilation and ventilation, and maintaining soil moisture. During the operation, the seedlings were straightened and the seedlings that had been planted too deeply in the autumn were buried deep and shallow, reaching the upper limit of the red skin in the enlarged diameter of the seedlings and the level of the surface.

(b), loose soil weeding

The role of loose soil weeding is to loosen the topsoil and cut off the capillary connection between the surface layer and the deep soil to reduce the evaporation of soil moisture, improve the ventilation, water permeability and water retention of the soil, promote the activity of soil microorganisms, accelerate the decomposition and transformation of organic matter, and increase soil The nutritional level is conducive to the survival and growth of young forests. The purpose of weeding is to eliminate the competition between weeds, shrubs and larch for water, gas, fertilizer, heat, and light, and to prevent grass and irrigation from harming young forests. Weeds have strong vitality, thick roots, and disorderly rooting. Not only do they compete with young forests for water and fertilizer, they hinder the development of forest root systems, and are prone to young plants being harmed by pests and weeds. Some weeds can also secrete toxic substances and affect the growth of young forests. The transpiration coefficient of weeds in general is large, especially in the vigorous growth season, it will consume a lot of water and nutrients, resulting in a significant decline in forest growth, especially in the drought season. Therefore, timely weeding and weeding are the basic measures for survival and rapid growth of young forests.

1. The number of times of weeding and weeding should be determined according to the specific conditions such as the environmental conditions of the planting site, tree species characteristics, planting density and management level, and should generally be carried out until the young forest is closed, which will take approximately 3 to 5 years. The season and frequency of weeding and weeding should be considered comprehensively according to the specific conditions of forestation and the growth characteristics of young forests. Generally speaking, young forests in the early period of afforestation have weak resistance and tending times should be increased, and they should be gradually reduced in the later period. In the first 1 to 2 years of afforestation, weeding is performed 2 to 3 times a year for 1-3 times, and 1 to 2 times a year for the first 3 to 4 years.

2. The season of loose soil weeding should be based on the annual growth law of young larch, soil moisture, nutrient dynamics and weed habits. Generally speaking, there are two growth peaks of Larix principis-rupperechtii within one year. The weeding time of the loose soil should be performed before the coming of two peak periods from May to June and from August to September. Loose soil weeding should take into account the distribution and growth status of forest roots, and loose soil depth, generally 3 to 5 CM is appropriate. It is necessary to remove weeds and loosen the soil, but also to avoid damaging the main root system of larch. Should also be combined with loose soil weeding repair hole surface, so that water conservation. For intercropping green manure plants, green manure plants can be turned into caverns to increase fertility, but can not injure larch seedling stems and roots before the seeds mature.

To do a detailed job shovel, generally from the larch about 10CM, the depth of 3 ~ 5CM, so shallow depth, the tree should be shallow, the tree should be deep, the whole point of the shovel to shovel it again, the job Go to the edge and cut off the grass roots. If there are any weeds around 10CM of young trees, they must be removed by hand to prevent damage to the bark or dead roots.

(III) Completely cutting irrigation

For the fast-growing and high-yielding pure forest of L. olgensis planted on barren hills, full-scale cutting and irrigation, and the regeneration and production of high-yield and high-yield L. principis-rupprechtii reforested on cutting lands of broad-leaved trees, will also require a good hard-leaved and dry-shaped combination of naturally sprouted leaves. Moth, such as white birch, wolfberry, aspen, etc., do not affect the growth of larch, the election to stay, in order to cultivate a mixed coniferous and broad-leaved forest, needle width ratio is generally more than 6:4 is appropriate. All the weeds and shrubs that affect wood growth in the woodland are cut off. The weeds near the seedlings are removed by hand. The weeds that are cut off are placed on the lower edge of the hole, and the seedlings cannot be pressed to ensure sufficient air ventilation of the larch seedlings. , And effectively clean up the forest environment to prevent overgrown weeds, causing a large number of brown backs breeding harm.

The time for full-scale irrigation should not be too late. It should be started in late June. Before shrubs cover the height of young trees of L. olgensis 2/3, it starts before influencing the growth of larch, preventing the cutting and weeding from causing young larch. The tree grows weak due to lack of light and poor ventilation. If we suddenly cut the shrubs, the young trees of L. principis-rupprechtii will suddenly turn from the shaded state to the exposure environment and cause death.

According to the specific conditions of the small afforestation class, the general autumn forest afforestation will be re-stepped in the spring of the year, and in the beginning of the summer, we will expand the hole and weed loose soil, and in midsummer we will carry out irrigation. Annually cut irrigation. After 5 years of general afforestation, the young forests will enter the state of closed vegetation, and young forest tending measures may no longer be implemented.

(D) Chemical weed control: For young plants grown in high-yield forests of Larix principis-rupprechtii, the weeds are lush. Sometimes, one loosening weeding and one full-scale irrigation can not control the impact of weeds on the young larvae, and weeding costs are excessive. With many labors, especially full-scale weeding and weed removal, with high labor intensity and the labor force of the forest farmers, the use of glyphosate in the band rooms (without the mixed forest created by the cutting leaves of broad-leaved trees) was carried out manually after the expansion and weeding in the planting belts. Or grass weed herbicide chemical weeding to kill the just germinating weeds, spraying glyphosate or grass weed herbicides to weeds in the summer to cut and weeding to kill and control weeds Growing up. When the herbicide is sprayed, the dosage should be increased in the more weedy land, and near the seedlings in the range of 20CM, so as to avoid injury to the seedlings and larch seedlings. In 1996, the weeding tests of glyphosate and grass weeds were conducted in Chengde County and Mengzi Forestry Bureau's Longtoushan Forest Farm. The herbicidal effects were all higher than 85%, and the purpose of weeding was achieved. The cost of weeding was much lower than the current labor. Cutting expenses. (Test results are shown in Table 4-9).

Table 4-8 Glyphosate and grass irrigation mixed weeding effect

Glyphosate treatment rate of grass grazing weeding effect (%)

(ML/M2) (ML/M2) 1 2 3 Mean

1 1.68 0.34 80 86 92 86.0

2 1.07 0.43 93 85 86 88.0

3 2.56 0.26 95 100 88 94.33

4 3.64 0.73 96 97 100 97.67

5 3.72 0.74 86 92 85 87.67

6 5.46 0.73 100 100 100 100

7 2.10 86.7

Practice has proved that the use of herbicides for young tending has a significant effect, low cost and high efficiency. However, the technical requirements for the use of herbicides are relatively high. Quantitative tests should be conducted first. Herbicides should not be completely relied on instead of expanding the holes to eliminate weeds and cut irrigation. They should be combined in two ways to prevent the long-term use of herbicides on young trees and woodlands of larch. Soil physical and chemical properties, soil microbes and the surrounding environment have an impact.

(five), forest land fertilizer management

Fast-growing and high-yield forests are intensively managed, watering and fertilizing are important measures, and their importance has been given widespread attention by forest researchers and forest managers. With the continuous improvement of intensive management, the area for watering and fertilizing forest land is continuously expanding, and the effect of forest management is becoming more and more significant.

In the process of growth, fast-growing and high-yield forests must absorb large amounts of nutrients from the soil. If the nutrients in the soil are insufficient, it will often become the main factor limiting the growth of forest trees. Therefore, the fertilization of forest land, especially the forests entering the fast-growing stage and the fertile soil of the soil, is an important measure for the implementation of intensive management of fast-growing and high-yield forests. The main role of fertilization in forest lands is to increase soil fertility, improve forest tree nutrient status, increase forest tree leaf area, increase biomass accumulation and forest tree growth, and achieve fast growing, high yield, and high quality.

1. Fertilization Generally, the fast-growing and high-yield forests of Larix principis-rupprechtii are all cultivated in the mountains. Although the fertilization effect is relatively large, the transportation is inconvenient and the cost is relatively large. Therefore, it is a good method to interplant green manure with forest soil and combine green manure with manure. The commonly used green manure plants are grasses, sedges, etc., and are perennial. Each year young leaves are turned into the soil in the rainy season, which can greatly increase soil fertility and improve soil properties without causing environmental pollution. If the traffic conditions are convenient and the land for afforestation is gentle, farm manure or green manure near the plantation site can also be used. Inorganic fertilizers have more side effects on forest lands.

The fertilization of Larix principis-rupprechtii afforestation field has great influence on the sapling diameter, height growth and timber volume growth, and the economic benefit is significant. According to the Hebei Provincial Academy of Forestry Experiments, in the larch seed orchard, fertilization experiments were conducted three years after afforestation. The annual growth of the young tree diameter was 220% of the control in the second year, and the tree growth was 135% of the control. France fertilizes in 20- to 40-year-old pine forests, applies 150-200 kg of phosphate fertilizer per hectare, and increases the volume of growth by 3.0-3.5 M3 per hectare per year. The results of 99 years of urea fertilization of L. principis-rupprechtii in the Mengzi Forest Management Bureau's Longtoushan Forest Farm showed that the best application was 200 g of urea, and the plant growth volume was 0.0041 M3 higher than the control, and 11.07 M3 higher than the control per hectare. Ratio 1:8.88 (see Table 4-10 for test results). It can be seen that the effect of nitrogen fertilizer is good and the economic benefit is significant.

Table 4-9 Fertilizer Volume Growth in 1999

Diameter 100g Urea 200g Urea 300g Urea 100g Urea + 100g Urea + Control

25gkh2PO4 50gkh2PO4

11CM 0.0069 0.0092 0.0056 0.0055 0.0072 0.0031

0.0061 0.0048 0.0045 0.0069 0.0065 0.0021

0.0040 0.0056 0.0040 0.0047 0.0049 0.0021

12CM 0.0045 0.0028 0.0084 0.0052 0.0047 0.0020

0.0064 0.0061 0.0073 0.0075 0.0067 0.0016

0.0029 0.0091 0.0049 0.0046 0.0055 0.0026

13CM 0.0098 0.0084 0.0113 0.0074 0.0088 0.0045

0.0049 0.0053 0.0053 0.0078 0.0066 0.0031

0.0051 0.0088 0.0077 0.0062 0.0061 0.0024

2. The conservation and utilization of water resources in afforestation land To build up fast-growing and high-yield forests of Larix principis-rupprechtii in the afforestation area, the water mainly depends on the degree of supply of soil moisture. If artificial irrigation is used, the cost is high and the water source is inconvenient, which is not easy to achieve. It is a practical way to protect and utilize natural precipitation and soil water resources to meet the demand of larch forest.

First, increase the depth of site preparation and enlarge the entire ground during site preparation. It can accumulate more water and improve the physical and chemical properties of the soil. In particular, the soil moisture conditions are slightly worse and the site preparation effect is significant; timely weeding and cutting off the capillarity layer of the soil layer can reduce the amount of capillary Evaporate to ensure soil moisture content.

Secondly, it is required to close forest stand as soon as possible to reduce direct sunlight exposure to the ground and reduce water evaporation. Stand closure is beneficial to intercepting precipitation, slowing soil erosion and surface runoff, thereby effectively retaining water.

Third, strengthen the protection of ground cover to accumulate precipitation.

(VI) Replanting

营造速生丰产林虽然对苗木规格、质量,整地质量和栽植技术都提出了严格的要求,但也往往因人为因素、苗木质量,栽植技术及外界环境条件等因素影响,造林后总有一部分幼苗死亡。营造华北落叶松速生丰产林,单位面积栽植株数比较少,当死亡株数超过一定限度时,就会影响速生丰产林单位面积产材量,达不到丰产的要求。因此,要在造林后的下一个季节补植,使保存率达到95%以上。补植要用同树种、同规格、同龄苗木。造林时可划出适当面积,栽植一块密度大的林地,以备补植用苗。

通过以上抚育措施,及时排除灌木杂草等对幼树的危害,不断提高林地的水分、养分水平,确保幼林正常生长,为速生丰产奠定可靠的基础。

㈦、修枝

对于营造的华北落叶松混交林,除对幼林地中的主要树种和混交树种全面松土除草、割灌外,还要对混交的阔叶乔灌树种进行修枝、摘芽等作业内容,灌木树种除外,以减少对目的树种的影响,培育良好干形。混交树种一般以白桦、花楸、黄檗萝、蒙古栎、沙棘、胡枝子等。对于阔叶乔灌木树种,一般主干由于竞争枝、侧枝、徒长枝较多而生长不良。由于幼林阶段植株较小,并且由于幼林生长较快,除对确实影响目的树种和混交树种主干生长的竞争枝、侧枝、徒长枝进行修枝外,一般不进行作业,待幼林郁闭后,根据情况进行幼龄林抚育作业。


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