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

Characteristics of Larch of North China

Larix principis-rupprechtii is the main afforestation tree species in the mountains above the mountains in North China. It has the advantages of fast growing, good material, wide use, and resistance to decay. It is a good tree species for fast-growing and high-yield forests, and it is also a good tree species for protecting forests because of its rapid growth and conservation of water resources.

Larix principis-rupprechtii, alias red e, is a gymnosperm phylum Pinaceae, Larix, scientific name Larix principis rupprechtii Mayr.

Section 1 Morphological Features

Deciduous trees, height up to 30m, diameter at breast height up to 1m, canopy conical. The bark is light brown or dark brown, irregularly squamous and longitudinally split, falling into small patches.

1. Buds: Buds are the basic organs for the growth and development of trees. The extension and flowering of tree trunks and crowns are all accomplished by the growth and development of buds. Among them, the apical buds are spherical or ovoid, with a diameter of about 4L and no hair. With branches of the same color, born in the trunk of the tree and the top of the lateral branches, born in the annual branches are nearly smooth, born in short branches and densely growing hair. Apical buds are the material basis for longitudinal and lateral extension of trees. Lateral buds are born below the terminal buds and are mostly. Four to six lateral buds adjacent to the top bud form regular axillary shoots, which is the basic condition for the growth and development of the crown. There are latent buds on the trunk and shoots. Under certain conditions, leaf clusters or branches can be formed, and they can also bloom and fruit.

2. Leaves: Leaves lanceolate or linear, spirally arranged on 1-year-old branches, clustered on short branches, leaves 2–3 cm in length, 1 mm wide, apex cuspidate or blunt, flat above, dorsal midvein bulge, There are 4 to 5 stomatal lines on both sides of the leaf. Leaf buds are born between leaf blades on one-year-old shoots, and leaves are later; leaf buds are plural, usually 5-6. The branches are born on short branches.

3. Branches: Branches evolved from lateral buds, latent buds, and leaf buds. One-year-old branches are light brown or yellowish-brown, hairy when young, glabrescent and subglabrous, with white powder; twigs of 2 to 3 years are yellow-brown to gray-brown or dark gray-brown. When the forest is densely shaded and the light is insufficient, the trunk is used as the central axis, and from the bottom to the top, from the inside to the outside, shoots are dry and dry, which is the beginning of natural pruning. When the main branch is broken, the top lateral branch of the uppermost layer can continue to grow in the trunk within 2 to 3 years, which is the so-called natural head replacement.

4, flowers: unisexual flowers, monoecious. 7-8 years young forest (planted forest) enters the flowering and fruiting period. The male ball peanut is on a 2 to 5 year long branch and has a small volume, 50 to 80 bud scales and 2 microsporangia. Peanuts on the 2-5-year-old short branches of the female body are larger, with 55-60 linear leaves, 60-70 larvae and 50-58 megaspore leaves. Male and female flowering overlap, pollen without airbags. Flowering in May.

5, cones: cones long oval or egg-shaped garden, fruit scales glabrous, the upper edge of a narrow, truncated wavy serrated, fruit scales more than 30. When the cone matures, it is light brown and shiny. It grows 2 to 4cm in length and has a cone diameter of about 2cm. The tip is truncated to a concave shape and the back is smooth. The scales are dark purple, slightly shorter than the species scale or nearly equal in length, and are often exposed slightly at the base of the cone. Leather fruit scales, two seeds per fruit scale. The cone matures from late August to early September.

6. Seeds: Seeds obovate and elliptic, with wing length of about 1.0 ~ 1.2cm. As the seeds mature, the cones are present. The seeds were small, with a length of 3.84L, a width of 2.4L and a width of 2.4L. The seed pods were flat and protruding. The basal body of the seedlings was flat and the seedlings of the seeds were covered with a seed thickness of 1M2. The seed wings formed a flat angle with the back of the seeds. Thousand grains weigh 5.3 to 6.9 grams.

7. Seedlings: Light greenish brown shoots, lanceolate leaves, solitary and spirally arranged, 2-year-old seedlings with branches, light red cortex below ground. Cuttage of the cuttings at the diameter of the seedlings is enlarged. There are short piles above the ground diameter in the flat seedlings. The diameter of the seedlings is formed by lateral buds, and there are generally no branches.

Section II Distribution

Larix principis-rupprechtii is mainly distributed in Shanxi and Hebei provinces. In the south, Laiyuan County in Shanxi Taiyue Mountain Area, 36°30′ north latitude, Mengzi Forest Management Bureau in the north to 42°37′ north latitude, and Saihanba Mechanical Forest Farm in Hebei Province, the easternmost distribution boundary of this species is 118°30° East. 'Latitude 43 ° 40', Chifeng City, Inner Mongolia Autonomous Region, Cao'erbang Banner, Wangyedian Forest Farm. In Wutai Mountain, Guanyi Mountain, Guandi Mountain, Hengshan Mountain and Taiyue Mountain in Shanxi Province, it is distributed at an altitude of 1800-2800m. There is a small amount of distribution in the west mountain of Beijing.

The natural Larix principis-rupprechtii in Hebei Province is mainly distributed in Yuxian and Yulu counties in Zhangjiakou City in the Hengshan Mountains, Weichang County, Longhua County in Chengde City, Yinshan Mountain in the Daxingan Mountains, Xinglong County in the Yanshan Mountains, and Fuping City in the Taihang Mountains and Mountains. The county, with an area of ​​about 6500ha, is located in the mountains above 1200m above sea level. This climate zone is a warm temperate-temperate continental monsoon climate.

The vertical distribution of natural forests of Larix principis-rupprechtii is a shady slope with an elevation of 1200-2800m, which is the highest component of the vertical spectrum of mountain forests. Because it can adapt to the cold weather conditions at high altitudes, it can reach the upper limit of the vertical distribution of forests, and it is connected to sub-alpine meadows.

The reason why Larix principis-rupprechtii can adapt to the harsh environment of cold and strong winds is determined by its own ecological and biological characteristics. It is a strong joy light tree species, small seeds, and with wings, high mountain wind spread distance, strong ability to germinate, after several generations of exercise to ensure that it is a pioneer species, in the upper layers of other plants. In addition, it can perform physiological activities in cold soils. When the temperature is around 0°C, the sap begins to flow. When the soil is thawing, the leaf buds are already open, which enables it to grow in a very short period (such as Saihanba Machinery The frost-free period in forest farms is more than two months old, and its life cycle is completed through a strong metabolism. Larix principis-rupprechtii has strong wind resistance, and larch growing on the windward side of the dam margin of Weichang County in Weibei County is subject to strong winds of about 5 grades in the fall, winter and spring. Although the trees are biased and dry, they still grow tenaciously.

Larix principis-rupprechtii has many advantages such as fast-growing, high yield, high quality, strong resistance and wide adaptability. After the liberation, a large number of introductions were made in vast regions of China. After years of cultivation and domestication, its adaptability has been greatly enhanced. Outside the natural distribution area, Larix principis-rupprechtii plantations were established from high mountain areas in western Sichuan at 32 degrees north latitude and Linkou County in Heilongjiang at 46 degrees north latitude, from Tianshan Mountain at 85 degrees east longitude to Changbai Mountain at 127 degrees east longitude. Among them, in the north of Hebei Province, the Mengzi Forestry Bureau, Saihanba Machinery Forest Farm, and Weichang County in Hebei Province have large and contiguous larch plantations. At present, most of the forest stands have been put into use in the middle, and some of them have entered the utilization period of the main cutting.

Section 3 Ecological Characteristics

Larix principis-rupprechtii is very light and hardy, and it is a shallow root tree species. Born on moist and fertile soil, it is the main forest composition and afforestation regenerative tree species in the middle and upper mountains of northern Fujian.

One-year-old seedlings grow under the forest canopy, and two-year-old seedlings do not tolerate lateral shade. In the Larix principis-rupprechtii plantation in the Mengzi Forestry Bureau of Hebei Province (in the territory of Weichang County in northern Hebei Province), due to the small canopy density of individual plots, the vegetation under the forest is sparse and the seeds are directly contacted with the soil after the trees are naturally planted. Natural regeneration is good, but as the forest stands grow, the degree of canopy closure increases, and the number of seedlings and young trees per acre gradually decreases. When the stand canopy density reaches above 0.6, there are few seedlings on the forest land. The growth of larch forests in shady slopes and low valleys, as well as in ravines, shows that forest trees are very tall, with small sharpness and straight trunks.

L. principis-rupprechtii is very hardy. The vertical distribution limit is the upper limit of the forest vertical distribution. It is suitable for being born in high-cold climates, and can normally grow under the weather conditions of an annual average temperature of -2 to -4°C and January average temperature of -20°C and a temperature of 0°C or more for about 80 to 90 days. In winter, it can withstand extreme temperatures of -39°C, and in summer it can withstand high temperatures of 35°C. Historically, there have been extreme cold temperatures of -42.9°C and high temperatures of 38.9°C. However, seedlings, especially young one-year-old seedlings, suffer from sunburn when the local surface temperature reaches 35°C.

The annual precipitation in the distribution area of ​​Larix principis-rupprechtii is 401.9-619.7L, and some sites can reach 885.4L. The average annual precipitation is 505.4L and the relative humidity is 57-67%.

Soil parent types and soil types. The root system of L. principis-rupprechtii is a shallow root surface distribution type, with undeveloped main roots, strong lateral roots, and strong adaptability to soils. It is found on leaching brown soils, brown soils and light chestnut soils developed on mountain brown soils and loess parent materials. All of them can grow, but they grow best on fertile, permeable, aerobic white mycelium, and slightly acidic mountain brown soils developed on granite, gneiss, sand shale and other parent rocks. For example, 34 years old larch in Xiaojiangjianangou, Xinfeng Forest Farm, Hebei Province, 44 counties with average diameter at breast height of 21.0cm, tree height of 18.2m, and 10.428 cubic meters per mu; Sanhe Yonglinchang Laoshuiquan 31 years old Larch, average diameter at breast height 19.1cm, tree height 14.3m, per mu accumulate 9.080 cubic meters; Longtoushan Forest Farm inspected Nianzizigou gate 37 years old larch, 39 acres, mean diameter at breast height of 25.2cm, height of tree 17.5m, volume of accumulate 10.397 cubic meters Meter. Larix principis-rupprechtii is more resistant to water and moisture in its distribution area, and it is mainly rooted in horizontal roots. Hi fertilizer, good growth, can not reach the required conditions of growth followed.

Section IV Community Characteristics

The Xiaowutai Mountain Nature Reserve in Hebei Province, which is in the western part of Hebei Province, is the upper limit of the forest distribution of Larix principis-rupprechtii natural forest. It is connected to subalpine meadows and connected to birch forests.

Some forest farms in the Mengzi Forestry Bureau in Hebei Province and the third township branch in the Saihanba Machinery Farm have large natural forest areas. Among them, mixed forests account for a large proportion, and most of them are mixed with white birch, spruce, and evenly poplar, and larch accounts for 3 to 70%. The larch forest age is 55-80 years, the DBH is 22-64cm, the tree height is 14.5-22.5 meters, the number of per mu plants is 16-55, and the mu reserve is 6.5- 18.5 cubic meters. The birch, poplar, spruce and larch are basically in the same forest layer and constitute the main forest layer, forming a single-layered forest of birch larch. Such as the Mengzi Forest Management Bureau, Longtoushan Forest Farm, Jizi Forest Park, Nanyang Tianyinpo 72, Linban Class 6 is a natural larch mixed forest with a forest age of 75 years. The tree species is composed of 7 falls, 3 birs and oil-clouds, and the average tree height. 17.92m, average diameter at breast height 24.6M, 31 plants per mu, and 12.264 m3 per mu. It is a typical natural mixed forest of Larix principis-rupprechtii and birch.

The population of Larix principis-rupprechtii plantations is relatively simple. Because there are more pure forests for many years, and the initial planting density is larger, single-layer forest facies of the same age are formed, and undergrowth plants are rare. However, the planted forests of the secondary hardwood forests are different. As attention is paid to the preservation of broad-leaved trees and the formation of coniferous and broad-leaved mixed forests, the vegetation resources are abundant, and the use of forest land is adequate, with good ecological and economic benefits. Such as: Mengzi Forest Management Bureau Longtoushan Forest Farm Jiji Forest Park 7 forest class 7 small class, an area of ​​209 acres, north slope, slope 190, 1300 meters above sea level, brown soil, soil thickness 60cm. Before the clear cut in 1975, the forest was 26 years old, and the tree species consisted of 6 birch 4 pods, an average DBH of 12.6 cm, an average tree height of 8.5 m, 69 mu, and a muti-population of 3.595 m3. Soil preparation, plant spacing 2×3m, acupuncture size 100×70×30cm, artificially planted 2-year-old Larch seedlings of North China in 1976, and the initial planting density was 222 mu. According to a survey conducted in the spring of 2000, the forest age was 24 years. The tree species consisted of 6 falls, 2 birs, 2 poplars, and pods. The number of trees per mu was 106. The average DBH was 12.0 M. The average tree height was 11.5 m. The mu-population was 5.746 m3, and the number of needle-leaved trees was 7:3. The stock ratio of 6:4, the forest is growing well. The above survey data shows that, in the same small class, the artificially updated coniferous and broad-leaved mixed forest is 2 years younger than the original broad-leaved mixed forest, but the accumulative volume is 2.151 m3 more. Practice has proved that it is a successful move to artificially renew larch on broad-leaved secondary forest cutting lands and form coniferous and broad-leaved mixed forests with broad-leaved sprouts.

Section 5 Growth and Development Law

Larix principis-rupprechtii is a native fast-growing tree species in northern Hebei Province. In recent years, under the circumstances of accelerating the sustainable development of land-based afforestation and forestry, the Mengzi Forestry Bureau of Hebei Province has managed to establish a large-area fast-growing and high-yield forest (that is, commercial timber forest) while managing the original natural forest of Larix principis-rupprechtii. Ecological public welfare forest.

First, natural forest

Natural forests and trees are completely regulated by natural differentiation and natural pruning. The survival of the fittest takes a long time, and its growth and development rate lags behind that of plantations. From the logging and analysis wood in the Beigou Yinglin District of Beigou Forest Farm in Beigou Forestry Bureau in Hebei Province and in the Yingqiao Forest District in Yange Berlin, generally, high growth accelerated after 6 years. Due to the high growth rate, the development of the entire canopy was promoted, and then the growth of the diameter and the growth of the volume began to accelerate. Twenty-five years later, high growth slowed down, while the diameter growth remained high until about 50 years. Between 10 and 25 years, annual growth is maintained at about 42 centimeters in growth, and its diameter can reach about 7 centimeters. By about 50 years, high growth basically stopped.

Second, plantation forest

(I) Nursery stage

The growth of Larix principis-rupprechtii was relatively slow at the seedling stage, and there were two peaks in the growth of one-year old seedlings. The first appeared in the middle and late July and the second in late August. The 2-year-old seedlings generally stop (cap) and grow high before the end of August. Autumnal rain is more likely to sprout in autumn than in dry areas. The annual growth period is about 110 days.

(b) Young forest stage

Larix principis-rupprechtii plantations grow faster than natural forests, mainly through the selection of seeds and appropriate trees; seedlings are cultivated and selected through artificial intensive management; artificial treatments are used during afforestation; a series of management measures are adopted after afforestation. For its growth and development to create a suitable environmental conditions. The fast-growing period started earlier, and generally the third year after afforestation (including 5 years of seedling age), the high growth started to accelerate. It can be seen that after planting, the seedlings also have a slow seedling stage. After the seedlings are slowly regenerated, the roots are restored and adapted to the afforestation sites. The rich lateral root-absorbing roots are also grown, and the ability to absorb nutrients and water is rapidly enhanced. At the same time, the shoots began to shoot new shoots, the number of lateral branches increased, the surface area of ​​the needles increased, the area of ​​photosynthesis increased, and the ability increased. If the site is better, the average growth rate of seedlings in the first three years after planting can reach 40 M or more, and the average annual growth in the fourth year is 70 M. The seedlings grow rapidly and thick. If the plantation with poor site conditions, especially the Larix principis-rupprechtii forest, is cut and then replanted, it will generally grow faster after the fifth year. In the 5th to 10th year, the average annual growth is about 50 cm. For example, at Mujiagou 91/17, Mengzi Forestry Bureau, Hebei Province, with an area of ​​530 acres, a half shady slope, a gradient of 15°-17°, and an elevation of 1350-1370m, the soil is brown earth with thick soil layers. Before the afforestation, there are natural mixed forests of poplar and birch. After clear-cutting, two-year-old seedlings of Larix principis-rupprechtii were planted and the initial planting density was 333 plants per mu. Through cuddling and management, after five planting seasons after planting, the number of preserved trees per mu was 284, with an average ground diameter of 3.5M, an average tree height of 2.6 m, and annual average high growth volume of 52 M. Up to 1.5m or more. In the tenth year or so, the forest began to enter the inspection trail (breast diameter 5M), and the volume of timber grows into the fast-growing period. Through surveys, the general acre growth volume can reach more than 0.25m3, up to 0.40m3. In the 10th to 15th years, the volume per mu can reach 1.0-4.5m3.

(III) Middle to mature stage

Larix principis-rupprechtii normally grows in the young and middle-aged forests in the fast growth period, and the high growth slows down after the middle age, which is mainly the diameter growth and the volume growth. In order to accelerate the growth of diameter and volume, it is necessary to carry out tending and cutting in time to create a good growth environment for forest trees.