How to plant Chinese fir (Chinese fir planting technology and management)

Although Chinese fir is not the world's three fast-growing tree species (the world's three fast-growing tree species: eucalyptus, poplar and pine), it is indeed a fast-growing timber tree species recognized by farmers in southern China. At the same time, because of its excellent wood properties, wide use and high economic value (compared with eucalyptus, poplar and pine), Chinese fir is widely planted in the southern mountainous areas and is also one of the first choice trees for the national fast-growing strategic reserve forest.

A well-managed and well-managed timber forest of Cunninghamia lanceolata can have a maximum stock of more than 30 cubic meters per mu during the main cutting period of 25 years, while the business cycle of a fast-growing and high-yield forest cultivated with clonal seedlings of Cunninghamia lanceolata can be shortened to 15 years. According to the cultivation experiment of fast-growing Chinese fir in Hengyang City, Hunan Province, Chinese fir can produce 25 cubic meters of Chinese fir with a diameter of 20 cm per mu within 15 years (volume, converted storage of 39 cubic meters).

So what are the technical points of building fast-growing and high-yield Chinese fir forest and realizing fast-growing and high-yield? Grass-roots forestry, on the basis of practical experience in production, summarizes the following four points.

Superior environmental soil conditions

▲ Small environmental conditions suitable for Chinese fir growth

Chinese fir is a tree species with shallow roots, which likes warm and humid environment, suitable growth temperature 15-23 degrees, likes humidity and is afraid of water, and grows best in acidic sandy loam.

According to these characteristics, it is very important to choose plots for planting fast-growing and high-yield forests. A plot suitable for building fast-growing and high-yield forests shall meet the following conditions.

1. Environment and climate: The climate in the mountainous area to the south of the Yangtze River in China is warm and rainy, which accords with the basic fast-growing conditions of Chinese fir;

2. Slope size: 10-30 degrees is cool, which is in line with the growth of Chinese fir and is conducive to the development of commercial activities;

3. Slope position: the middle and lower parts of semi-shady slopes such as southeast, northeast, southwest and northwest, valleys and basins, with superior microenvironment and climate;

4. Soil conditions: sandy loam with loose acidity, good permeability and rich organic matter, with phyllite, shale, slate and sandstone as the best parent rocks.

Among them, Fujian, Guangdong, Guangxi, Yunnan, Guizhou, Hunan, Sichuan and Jiangxi have the most favorable environmental conditions. The farther south, the longer the growth period of Chinese fir, the faster it grows.

Good varieties and strong seedlings.

▲ Tissue culture of improved seedlings of Chinese fir clones

This is of great significance to realize fast growth and high yield of Chinese fir. It is necessary to select fast-growing Chinese fir strains carefully selected from all over the country, and select one-year-old strong seedlings with developed roots, full lignification, more than two rounds of lateral branches, no mechanical damage, no pests and diseases, and complete terminal buds.

Among them, clonal cutting seedlings and tissue culture seedlings cultivated by improved Chinese fir varieties are the best, but the price is relatively high.

Suitable afforestation density

▲ Suitable initial planting density of Chinese fir.

The fast growth and high yield of Chinese fir are closely related to afforestation density. Grass-roots forestry has talked a lot about the initial planting density of Chinese fir cultivation, which has also aroused heated discussion among many netizens, but the core views are nothing more than two points.

First, afforestation plots with superior site conditions generally focus on cultivating large-diameter timber and advocate sparse planting. The initial planting density should be controlled at 120- 160 plants per mu, and the highest planting density in northern marginal areas (such as southern Anhui) should not exceed 160- 180 plants; Second, the afforestation plots with general site conditions generally cultivate medium-sized fast-growing timber, which can moderately increase the initial planting density, and control the initial planting density at about 180 plants, so as to win by quantity, increase the unit yield as much as possible, and maximize economic benefits.

Timely and meticulous management measures

▲ Young Cunninghamia lanceolata forests with timely tending and good growth.

"Three-point planting and seven-point management" is a classic practice summarized by Chinese fir growers and needs to be followed in practice.

1. Tending mode of young Chinese fir forest: 2+2+2, that is, continuous tending for three years, twice a year;

2. Tending mode of young Chinese fir forest: The main method is "knife cutting" to remove weeds and short irrigation, but the best method is "hoe cutting", which can not only remove weeds and irrigation, but also loosen the soil, which is of great significance to the fast growth and high yield of Chinese fir. However, due to the shortage of labor, hoeing is rarely used in practice at present;

3. Tending time of young Chinese fir forest: the first tending should start in mid-May and end before high temperature in summer in June; The second tending should start in late August and end in early September, so as to make full use of the fast-growing period of Chinese fir twice a year, that is, the growth of summer shoots in June and July and the growth of autumn shoots in 9- 10, so as to achieve the goal of fast growth and high yield.