How to improve the afforestation technology of Cunninghamia lanceolata wood?

How to improve the afforestation technology of Cunninghamia lanceolata wood?

Cunninghamia lanceolata and Pinus massoniana are unique high-quality fast-growing wood coniferous species in southern China. For a long time, Cunninghamia lanceolata plantation has been planted in a large area of Cunninghamia lanceolata producing area in South China. Because of its fast growth, short rotation period, high nutrient consumption, low litter and low nutrient content, poor self-fertilizing ability of woodland and soil erosion, continuous planting of Cunninghamia lanceolata leads to soil fertility decline, habitat deterioration, stand stability and stand productivity decline generation by generation. In the sixties of last century, China began to pay attention to the decline of soil fertility of artificial forest, especially Chinese fir plantation. With the in-depth understanding of forest resources and ecological environment, forest has the dual role of providing many renewable resources and giving full play to public welfare. In the past, the artificial forest was mainly pure coniferous forest, and changed to coniferous and broad-leaved mixed forest. The construction of artificial coniferous and broad-leaved mixed forest base is a key forestry project carried out in the early 1980s. Through more than 30 years of cultivation and research, coniferous and broad-leaved mixed forest has obviously shown its functions and characteristics. According to the research at home and abroad, compared with pure forest, the construction of coniferous and broad-leaved mixed forest has the advantages of improving soil, conserving water, improving material, high comprehensive productivity of woodland, strong ability to resist disasters and so on. at the same time, optimize the structure of forest resources and promote the diversification of artificial forest species, simulate natural conditions, develop ecological forestry, take the road of efficient and coordinated sustainable development of forestry, and realize the overall optimal benefit of forestry. It has become the consensus of forestry workers to build coniferous and broad-leaved mixed forest, improve soil fertility of coniferous woodland and improve woodland productivity and stand stability.

The mechanical properties of wood directly determine the utilization rate of its subsequent processing. therefore, improving the mechanical processing level of wood is very important to improve the quality of wood products, broaden its application fields and realize high value-added utilization. To a certain extent, coniferous and broad-leaved mixed forest is beneficial to wood control. Some studies have shown that the wood density, shrinkage and mechanical strength of tree species in mixed forest are higher than those in pure forest, and the anatomical characteristics of wood are good. However, at present, there are no afforestation methods to improve the wood properties of Cunninghamia lanceolata and other wood.

(1) Fine seedling cultivation: select the nearest excellent provenance and cultivate high quality Chinese fir seedlings.

(2) soil preparation and fertilization: vast plots are selected for land preparation and afforestation, flat plots with slopes less than or equal to 15 degrees are selected for comprehensive soil preparation, and slopes with slopes greater than 15 degrees are partially prepared; when local soil preparation is carried out on sloping plots, contour steps are built, the ladder width is 2.0-3.0 m, and there is a place for mechanical U-turn. The suitable length × width × depth specification is 50 × 40 × 40 cm, and the plant spacing is 2.0-3.5 m. According to the soil fertility of the forest land or stand, 0.25-0.75 kg of base fertilizer is applied to each hole, and the topsoil is backfilled after fertilization.

(3) Tree species configuration: the high quality Chinese fir seedlings obtained after step (1) are mixed and planted in the afforestation land obtained after step (2). The mixing mode is one or more of Cunninghamia lanceolata and Pinus massoniana, Minnan, red beech, Liriodendron chinense and Schima superba.

The afforestation land below 500 meters above sea level is hilly land, and the mixed mode of hilly land is "3 Cunninghamia lanceolata + 2 Masson pine + 3 Minnan + 2 red beech" or "7 Cunninghamia lanceolata + 2 red beech + 1 Minnan". The total is 100%, that is, every 3 trees per row of Cunninghamia lanceolata, 2 trees per row of Pinus massoniana, 3 trees / row of Minnan and 2 trees / row of red beech mixed planting Or every 7 trees / row of Cunninghamia lanceolata, 2 plants / row of red beech and 1 plant / row of Minnan mixed planting

The afforestation land at an altitude of 500-800 meters is mountainous, and the mixed mode in the mountain is "8 Cunninghamia lanceolata + 2 Liriodendron chinense" and "6. 5 Cunninghamia lanceolata + 2. 5 Minnan + 1 Schima superba". The number represents the proportion of each tree species, that is, every 8 trees per row of Cunninghamia lanceolata and 2 trees per row of Liriodendron chinense, or every 6. 5 trees per row of Cunninghamia lanceolata, 2. 5 trees per row of Minnan and 1 tree of Schima superba

(4) planting: choose to plant in cloudy or rainy days between Rain Water and Qingming Festival, select 1-year-old seedlings above 50cm, plant in a single hole, do a good job of disease and pest quarantine before seedling adjustment, hold the seedlings with one hand when planting seedlings, place the seedlings in the soil hole and cover half of the soil, then gently lift the seedlings upward to stretch the roots, then press the soil tightly, then cover the soil, and tamp the roots with a hoe. Make the base of the seedling uplift a small mound with a height of 3-5cm, check the survival of the seedlings 30-40 days after planting, and replant the dead seedlings in time.

(5) upbringing management:

① cutting, irrigation and weeding: in May and September of each year, weeds affecting the growth of trees are removed, and miscellaneous irrigation and non-target tree species are cut down to ensure a reasonable supply of light, water, fertilizer, gas and heat for trees.

② tending thinning: continuous tending for ten years, knife caress or burrowing hoe 2-3 times a year for the first three years, knife caress 1-2 times a year after three years, hoe caresses, cut down all thatched grass, cut down miscellaneous irrigation and Tengben, remove sprouting, cultivate and correct, adopt the principle of keeping small and large, good quality, thin density, and uniform thinning, so as to design first, mark later, and then cut down, so as to put an end to mistakes and leaks. To ensure a reasonable nutrition space for trees, 30-50 living trees with a DBH of 4-5cm were evenly transplanted in 6-8 years, and 50-55 trees per mu were retained for directional cultivation.

③ pruning and shaping: combined with cutting, shrub, weeding or tending thinning, pruning and shaping is carried out during the dormant period, the dead branches and diseased branches under the crown are removed, the pruning height does not exceed 1 × 3 of the total tree height, the pruning port is smooth and does not hurt the bark, and the straight stem and pruning of beech trees are carried out in the first five years [Jishan Huayao]

④ topdressing: open semilunar grooves on the square bank of the tree to evenly spread compound fertilizer and cover the soil, fertilize once in the spring of that year, and then every 3-5 years in spring, mainly compound fertilizer, and remove weeds before each fertilization.

(6) Archives and information management: establish a professional archives management system, establish special files for all technical, management and financial data related to project planning and design, implementation plan and operation design, quality tracking, inspection and acceptance, fund use, effectiveness monitoring, etc., and gradually improve the project file management.

By combining Cunninghamia lanceolata with one of Pinus massoniana, Minnan, red beech, Liriodendron and Schima superba

The inter-plant or inter-row mixing of several species intensifies the competition between Cunninghamia lanceolata and other tree species, and the broad leaves such as Minnan, red beech, Schima superba and Liriodendron chinense are easier to rot to form humus and are rich in a variety of mineral nutrients. These mineral nutrients are absorbed by Cunninghamia lanceolata and accumulated in the trunk wood to improve the wood properties of Cunninghamia lanceolata. Compared with the traditional pure Chinese fir woodland, the basic density of the trunk of Cunninghamia lanceolata increased by 8. 5%. 16%, the fiber length increased by 1. 32%, the fiber length increased by 1. 32%, the fiber width increased by 1. 5%. 83% by 2. 61%, the bending strength by 36. 9%. 91% by 79. 39%, the flexural modulus of elasticity increased by 63. 5%. 87% by 90. 7%, and the compressive strength along the grain increased by 14. 44%, 27. 48%.