"The Technology of Fast-growing and High-yield Forest of North China Larch"

Second, pests

Underground pests are more harmful. In the northern regions, there are mainly beetles, tigers, earthworms, and gill locusts. The control of underground pests can be carried out by bait and black light trapping according to the adult eclosion stage, and 20% dimethoate and 25% phoxim are used for chemical control. , can kill larvae effectively.

In the process of sales and distribution of seedlings, pests and diseases also often spread and spread along with seedlings. Therefore, the seedlings should be quarantined. Seedlings destined for foreign countries should be quarantined according to national and regional regulations for key pests and diseases. The state stipulates that there are pine needles, erythema disease, crown gall disease, larch shoot disease, larch seed wasps, and Hebei Province's larch cancer. For diseases such as swollen diseases and root cancer, if any quarantine objects are found in the region or country, they should be destroyed immediately to prevent the spread from causing troubles. Seedlings without quarantine certificates cannot be transported and mailed.

The eighth quarter raised seedlings

First, seedling investigation

Seedlings investigation should be conducted before raising seedlings. The purpose is to identify the yield and quality of seedlings in order to formulate nursery stock supply and marketing plans and production plans. The main method adopted in the national nursery seedling technical regulations is the sampling survey method. The specific methods are as follows:

(I) Determination of plot area

The area of ​​plots is mainly determined according to the density of seedlings. Generally, the area occupied by 20 to 50 seedlings is the plot area.

(II) Determination of the number of plots

The number of rough estimated plots N is calculated as follows: N=(T*c/E)*(T*c/E)

In the formula: T: reliability index (reliability is set as 95% when rough estimation, then T=1.96);

c: coefficient of variation;

E: Permissible error percentage (E=5% at 95% accuracy).

Where T, E are known numbers, c is an unknown number, but past data can be borrowed. If no empirical data is available, it can be determined based on the number of plants in each plot. According to the probability of a normal distribution, the range difference is generally estimated by 5 times the standard deviation. Then the standard deviation S and the coefficient of variation c can be calculated by the following two equations.

S=(xmax-xmin)/5

c%=(average of S/x)*100

Where: xmax - the maximum number of plots;

Xmin - the minimum number of plots;

x - the average number of plants in the plot.

(c) Setting of plots

In order to make the sample site representative, the mechanical method is often used for sampling when the seedlings are distributed evenly and the growth conditions are basically the same.

(IV) Survey of Seedlings in Sample Sites

First, the number of seedlings in the sample plots was investigated on a block-by-block basis. The height of the seedlings was measured with a meter ruler, and the diameter of the seedling base diameter was measured with a caliper to indicate the quality of the seedlings. According to experience, investigating 60 to 200 strains can ensure that the survey accuracy of seedling quality is above 95%. The specific investigation of how many strains should be determined according to the uniformity of seedling growth. Seedlings grow neatly and the number of trees surveyed can be less. From the side of the nursery, a certain distance is set in the nursery to mechanically point, and the four points of the quadrats are selected on the selected spot. The number of the mark is marked and the system is established. Then the seedlings are surveyed according to the order of the land.

(v) Accuracy calculation

After the investigation of nursery stocks is completed, the accuracy must be calculated and the yield and quality can be calculated when the accuracy is qualified. The accuracy is calculated as follows:

Average number of samples

Sample standard deviation

Sample standard error

Error percentage (relative error)

Accuracy

If you do not meet the accuracy requirements, you will need to make additional plots. The method is to calculate the coefficient of variation by using the materials that have been investigated, and substitute the formula for the number of rough estimates, and determine the number of plots that should be set. In the survey area, additional sample plots were arranged mechanically and investigations were conducted at the same time.

(vi) Calculation of seedling production and quality

According to nursery area and plot area, the total output and yield of seedlings at all levels are calculated.

Second, raise seedlings

1. The seedlings are sprayed once every 3 to 5 days before the emergence of the seedlings, so that the soil layer distributed in the roots is in a moist state. The seedlings are used to dig the seedlings twice and the seedlings are deepened by 20 cm. A large number of seedlings must be raised to reduce lateral roots and fibrous roots. Injury, the proposed seedlings are wrapped in straw and quickly transported to the selection of seedlings shed, and spray moisturizing, to prevent seedling root wind and sun, in the selection of seedlings shed within the classification.

2. The purpose of grading seedlings for seedlings classification is to standardize the seedlings in the nursery, ensure afforestation with strong seedlings, and reduce the seedling differentiation after afforestation. The grading standards are mainly based on the morphological and physiological indexes of seedling quality. The morphological indicators include geology Root height, root height, and root length (5.0 cm or more and long lateral roots), and morphological indicators can be divided according to the standard requirements for afforestation seedlings. Physiological indicators include seedling color, degree of lignification, growth of seedlings, and root growth potential. In order to ensure the vitality of seedlings, physiological indicators are used as grading control conditions, and all physiological indicators cannot be treated as waste seedlings. The condition of strong seedlings is to have a certain height and thick trails, no growth phenomenon, full lignification, no pests and mechanical damage, high ratio of no more than 90 times, a developed root system, short and thick main roots, more lateral roots, Evenly distributed, the top buds are robust and full.

3. For the seedlings after grading, the seedlings shall be slushed and falsely valued in time, and the temporary false value and wintering false value of the sham implants.

(1) Temporary Implantation: Temporary Implantation is a short-term pre-planting to afforestation prior to afforestation. It is advisable to choose a planting site that is well shaded, sheltered, and well-drained. The planting line should be perpendicular to the direction of the main wind, excavate the false planting ditch, and put the seedlings in bundles in a single row, and bury the roots and bases with wet soil. Stepping.

(2) Wintering and planting: (see Section IV, Section V. Winter Overlook).

4. It is very important to package seedlings with straw or straw. After the seedlings have mud or water-retaining agent, the roots of the seedlings are placed on the roots, the bundles must be strong, and the labels should be labeled. The labels indicate the origin, seedling age, number and level of the seedlings. During transportation, it should be properly watered and kept moist. Immediately after transporting it to the afforestation site, open the package and leave it on the spot.

Section IX Establishment of Nursery Archives

First, the significance of establishing a nursery archives

By continuously recording, accumulating, arranging, analysing and summarizing the use of nursery land, the growth of seedlings, technical measures for seedling raising, material usage, and daily operation and management, the growth laws of seedlings can be grasped, and the experience of seedling cultivation techniques can be analyzed and summarized. Formulate production quotas to provide the basis for scientific management.

Second, the main contents of the nursery archives

The nursery archives include the nursery plan archives, field management technical archives and scientific trial archives.

(1) File of Nursery Project

Plan management is one of the important measures for the management and management of nurseries. Accumulating the nursery plans year by year, it is possible to sum up a practical nursery plan and production quotas, continuously improve the management level, and gradually achieve high quality at a lower cost. High-yielding seedlings create better economic and social benefits. The nursery plan archives include seedling seeding quantity and seedling production plans at various levels, production and employment plans, fertilizers, medicines and materials plans, nursery cost plans, etc., and draw a plan of the land use situation of the nursery each year to record the utilization and cultivation of the land. It is convenient for the analysis of the relationship between soil fertility change and cultivation in nursery land, and provides a basis for rational crop rotation and scientific management.

(B) Field Management Technology Archives

Each year, seedling growth status and technical management measures are systematically written and recorded in the form of letters or tables to analyze and summarize the experience and lessons of nursery management and improve seedling raising techniques.

1. The records of seedling and phenology observation records the growth and development process of seedlings, and grasp the effects of their growth and development laws and natural conditions and human factors on the growth and development of seedlings in order to determine the management measures.

During the observation of phenology, a representative fixed standard plot should be selected, and 20 to 50 representative seedlings should be selected as fixed observation plants within the fixed standard plots. The seedling stage, the true leaf appearance stage, the leaf development stage, and the top bud formation should be recorded. The date when the phenology of leaves, leaf discoloration, deciduous, etc. occurs is divided into the initial period and the peak period. The phenological period is described by the following characteristics:

(1) When cotyledons or young shoots are individually excavated, the seedlings will begin to emerge, and if they are unearthed uniformly, they will be unearthed.

(2) When 50% of the seedlings have true leaves, they are the true leaves, and most of them are flourishing.

(3) A few bud scales split, and the upper part of the bud shows green leaves as the beginning of the leaf development period, and more than 50% of the seedlings appear as the leaf development period.

(4) When a few seedlings begin to cap, they are the initial stage of the formation of the top bud, and more than 50% of the top buds of the seedlings form the peak period.

(5) When a few seedlings have changed their leaf color, they are the initial stage of leaf discoloration, and when there is more than 50% of the leaf color of the seedlings changed from green to other colors, it is the peak of the discoloration of the leaves.

(6) When a few seedling needles begin to fall off, they are the initial stages of deciduous leaves, and when more than 50% of the needles of seedlings fall off, they are the peak period.

2. The investigation records of seedling growth regularly surveyed the high-diameter growth of the fixed seedlings within a fixed standard area. The survey was conducted twice a month, and 10 or more surveys were conducted each time. The growth and development patterns were explored and effective cultivation measures were taken.

3. Technical files for nursery technical measures The technical measures used in the nursery's annual production of nursery seedlings shall be recorded and registered in different nursery methods in order to analyze and summarize nursery experience and improve seedling raising techniques.

4. The meteorological observation file nursery shall establish meteorological observation stations (points), or obtain meteorological data with the nearest local meteorological station, analyze the relationship between meteorological factors and the growth and development of seedlings and pests and diseases year by year, seek advantages and avoid hazards, and promote the quality and yield of seedlings.

5. The nursery job log records the daily work and labor arrangement of the nursery, and measures the amount of nursery work, the use of materials, and the accounting costs.

(c) Scientific test files

Scientific experimentation is an important way to improve seedling raising techniques and benefits. Each year, scientific experiments conducted in conjunction with production are recorded in detail, and lessons learned are learned to facilitate the improvement of management and management.

Third, the establishment of a nursery file requirements

The nursery archives are the true reflections and historical records of the whole process of nursery growth, and they are also the basis for continued production. Therefore, we must do:

(1) To formulate a production plan must be realistic and increase year by year.

(2) Archiving texts and forms must be filled in by the technicians themselves, and the construction staff should cooperate closely.

(3) Field observation should be conscientious and responsible, seek truth from facts, be timely and accurate, and be required to observe and record at the same time, in order to be concise, clear, and comprehensive.

(4) After a production cycle has been completed, it will be promptly summarized, analyzed and summarized to find out the regular things to guide production.

(5) According to the succession of materials or the degree of importance, together with the summary classification, sorting and binding, registration and filing, and long-term preservation.

Chapter IV Afforestation

Section 1 Selection of Reforestation Sites

According to afforestation tree species, selecting appropriate afforestation sites is an important part of appropriate lands and trees. The success of the selection of afforestation land is related to the success or failure of afforestation, and it is the key condition for whether or not the larch trees can reach rapid and high yield. When selecting land, according to the ecological and biological characteristics of Larix principis-rupprechtii, natural and artificial Larix principis-rupprechtii should be used as a reference for comprehensive consideration of climate, soil and other factors, taking into account the relevant conditions of transportation, social labor and other relevant sources. High-quality, high-standard and strict-demanding principles, with targeted selection, truly “appropriate land and suitable trees”, in order to give full play to the characteristics of tree species and production potential of forested land, and achieve the current technology and economic conditions of the forestation land. Possible high production levels.

To choose afforestation land, we must study the site factors of the afforestation land and classify them by scientific methods to find out the suitable site conditions for the construction of high-yield larch forest in North China, and provide scientific basis for the selection of afforestation land.

First, site factor

Site refers to the combination of environmental conditions (biological, soil, climate) that exist in a specific location. Site factors generally include three major categories of physical environmental factors, including climate, topography and soil, vegetation factors, mainly referring to the type of vegetation, plant composition, coverage and growth status. Among these factors, for a specific region, a tree species is mainly studied and applied to those site environmental factors that play a leading role in the growth and development of tree species.

1. The relationship between site factors and growth and development of Larix principis-rupprechtii

(1) Climate factors: The Weibei Mountains belong to the semi-arid and semi-humid continental monsoon climate in the cool and temperate zone. They are colder, and the temperature difference changes greatly. The frost-free period is short. The annual precipitation concentrates in July-August, and the rain and heat occur in the same season. Wind, sand, and frost disasters occur from time to time. In addition to the dry, low-lying soils, low air humidity, and poor aptitude of the low-lying hills in the region, most of the remaining areas are above the mountains, especially the shady slopes, semi-shade slopes, semi-sunny slopes, and valleys. In addition to the winter and spring seasons, the regional microclimate is cool and humid, and the soil is fertile. The special climatic conditions make the forest vegetation including L. olgensis very dense.

(2) Precipitation

The lower limit of precipitation in the natural distribution area of ​​Larix principis-rupprechtii is 400 mm, while in the northwestern part of the upper plateau of the Bangladesh Forest Management Bureau in the less rainy area, the annual precipitation is less than 400 mm, while L. principis-rupprechtii can still grow normally and perform well.

(3) Natural disasters such as wind, snow pressure and rainstorm

Through 40 years of cultivation and management of Larix principis-rupprechtii, the Mengzi Forestry Bureau has cultivated nearly 400,000 mu of pure larch forest and nearly 300,000 mu of mixed forest with mainly Larix principis-rupprechtii. Practice has proved that the harm of wind to trees is very serious, and it also proves that natural disasters such as snow pressure, rain, etc., have a direct relationship with the degree of damage and wind size. Therefore, when choosing afforestation sites, try to avoid Mandian and tuyere.

2. Terrain factors are also called topographic factors. Topographic factors are indirect ecological factors. Different altitudes, different slopes and slopes in the afforestation land can indirectly affect the natural factors such as sunshine, precipitation and soil temperature, humidity, etc. that affect the growth and distribution of forest trees.

(1) Altitude: After many years of cultivation practice, Larix principis-rupprechtii grows rapidly within the range of 1000-1600m above sea level. Just as the altitude rises, the growth situation is affected accordingly. As Larix principis-rupprechtii is a light-loving tree species, its temperature will decrease as its altitude increases, and its humidity will increase its growth. Therefore, according to the local annual precipitation and annual average temperature, compare the extent of the impact on the growth of larch, and then determine the corresponding altitude range. Under normal circumstances, the average temperature is reduced by 0.56°C for every 100 meters above sea level. At lower altitudes, as the altitude decreases, the temperature increases, the evaporation increases, and the soil water content decreases, which affects the normal growth of Larix principis-rupprechtii. Another constraint. Practice has proved that between 1000m and 1600m above sea level, it not only meets the peculiar characteristics of L. principis-rupprechtii, but also provides suitable temperature and humidity for it. Therefore, it is said that this altitude region in the northern part of the Weibei Mountains is a relatively fast-growing and high-yielding forest of L. principis-rupprechtii. Good area range.

(2) Slope orientation: Because L. principis-rupprechtii is a species of hi-light tree, its growth has higher requirements for soil thickness and humidity, and the difference in slope direction has significant effects on the construction of fast-growing and high-yield larch forests. In the low-altitude areas of northern Hebei, sunny slopes generally have strong sunshine, high temperatures, low soil moisture content, and sparse vegetation, which is a dry and hot slope. At the same time, most of the soil layers are relatively thin and have a high content of gravel, which is not suitable for the construction of high-yield forests of Larix principis-rupprechtii, which is disadvantageous in terms of soil and fertility. Due to the semi-arid to semi-humid transitional climatic type of Mengwei Forest Management Bureau, in the case of persistent drought, due to the thin soil layer and the severe shortage of soil moisture, the growth of larch, especially the young forest, often causes serious physiological drought. Growth or even death. However, with the increase of altitude, in the semi-sunny slope above 1200m in Zhongshan, many soils are fertile and moist, and the light, heat and water factors are suitable for the growth of Larix principis-rupprechtii. For example, within the scope of the Mengzi Forest Management Bureau, the general mountainous area is located at an altitude of 1000 to 1500m, and the temperature does not change significantly with elevation. Therefore, the temperature of shady slopes and semi-shaded slopes can also meet the growth of Larix principis-rupprechtii. At the same time, the shady slope has the advantages of fertile soil, more vegetation and good soil structure. Practice has proved that Larix principis-rupprechtii grows well on shady slopes above 800 meters and semi-sunny slopes at middle altitudes, and is very suitable for the construction of high-yield larch forests.

(3) Slope position: Different parts of the same slope influence the growth of Larix principis-rupprechtii. Ridges and watersheds grow weakly. First, because the area is mostly residual soil, soil is thin, there are many stones, soil fertility is poor, and water storage capacity is weak. In case of drought, it often causes different degrees of physiological drought; Second, the edge of the forest is affected by the strong winds in the northwest. , Often caused by dry branches in the northwest, trunk tilt, dry bending and other phenomena. Most of the soil on the slope or low-lying soil is alluvial or alluvial soil, which is relatively moist and thick, which is very beneficial to the growth of Larix principis-rupprechtii. Therefore, we must avoid the ridges and the watersheds when we choose the land, and we must choose the middle and lower parts of the mountain.

3. Soil factors Soil conditions are the basic factors that affect the productivity of L. principis-rupprechtii plantations, and are mainly manifested in the following aspects:

(1) Soil thickness: The soil thickness determines the range of use of the soil by tree roots. Larix principis-rupprechtii is a shallow-rooted tree species. Its root system is usually characterized by horizontal lateral roots. It is generally close to the surface, but the main root is not obvious. The root system is mainly distributed in the range of 20 to 50 cm, accounting for 70%. However, because the Larix principis-rupprechtii is fertile and moist, the soil thickness requirement is not less than 50cm. With the increase of soil depth, it is conducive to lush vegetation and individual plant growth. Litter leaves a large amount of organic matter into the soil. With the increase of soil moisture, organic matter is further decomposed, which greatly promotes the growth of larch. Thin margins of ridges and larch along the watershed often cause uprooting due to wind force. For example, in the 35-year-old larch forest on the edge of the Longtangou ridge in the Mengzi Forest Management Bureau, Mengzi Forest Farm, the soil thickness is about 30cm. Due to strong winds, large trees with diameters of about 17-25 cm are uprooted. Therefore, when the normally-built larch of North China is selected, the soil thickness avoiding the tuyere should not be less than 50cm. As the soil thickness increases, so does the productivity of larch.

(2) Thickness of soil humus: The decomposition of the humus layer by microorganisms forms the organic matter of the soil and increases soil fertility, which greatly promotes the growth of Larix principis-rupprechtii.

(3) Status of soil moisture and soil fertility: Larch afforestation is generally concentrated in cutting sites on hill slopes. Soil moisture mainly comes from natural precipitation and groundwater, and it is formed in weathering formed by granites and gneisses. The base rock does not leak water, which is conducive to the fixation of atmospheric precipitation. However, in the soil formed by the weathering of limestone, natural precipitation is easily lost, which can easily cause physiological drought of larch and affect normal growth. The level of soil fertility is affected by comprehensive factors. In the forest land where larch is continuously planted, the soil fertility is greatly reduced due to soil fertility degradation and acidification. However, in the broad-leaved forest, larch is formed. Because of its complex soil structure, a large amount of decomposition products of forest litter are accumulated in the soil. ―Organic matter is conducive to improving the structure and physical and chemical properties of soil, regulating water content, and has a significant effect on improving soil fertility. Therefore, it is a powerful measure to overcome the decline of soil fertility in coniferous and pure forests by creating afforestation with mixed forests or “introducing needles into and expansively” (planting larch plants in natural broad-leaved forests).

In summary, the site conditions for afforestation sites are different, and the yield and quality of wood produced on a unit area will vary greatly. However, in all site factors, especially for a region and a tree species, not all factors have an important influence on the growth of larch. Only the environmental factors that affect the growth of L. principis-rupprechtii are found, such as the altitude mentioned above. Slope, aspect, and soil conditions, etc., using scientific classification methods, can select suitable site conditions for the establishment of high-yield larch forest in North China.

4. Site type division Site type is the most basic classification unit in forest site classification system. The type of forest site is the general term for areas with similar soil nutrient and moisture conditions. In the site classification, we combine the sections with similar site conditions and the same productivity but are not connected, and classify them into one category. We choose afforestation species by type and design afforestation measures. For Larix principis-rupprechtii, it is through the division of the type of the site to find the suitable afforestation land for the characteristics of L. principis-rupprechtii, and it is truly suitable for the land to lay the foundation for its rapid growth.

The division of site types can be divided into indirect methods based on environmental factors and direct division methods based on the average growth index of artificial forests. However, for the classification of site conditions of L. principis-rupprechtii afforestation sites, indirect use based on environmental factors is used. The main method is. According to the environmental factors, especially the similarities and differences of environmental factors, the hierarchical grouping divides the site condition types. Hebei Provincial Forestry Survey, Planning, and Design Institute used the World Bank loan “Forest Resources Development and Protection Project” in Hebei Province in 1995 to establish a site type for the construction of a fast-growing and high-yielding forest of North China larch. During the years, he had presided over the compilation of the "Typical Design of Hebei Province's Afforestation", which was based on the dominant environmental factors for the classification of site types for forestation. Based on the characteristics of northern Fujian mountains, according to the years of forestry production practice research, site conditions were divided according to the four dominant environmental factors such as elevation, aspect, soil type, and soil thickness. According to the biological and ecological characteristics of Larix principis-rupprechtii, suitable conditions were listed. To establish the site type of the fast-growing and high-yielding forest of Larix principis-rupprechtii. Table 4-1.