How to carry out maintenance and management of large spruce saplings after transplanting

Large spruce saplings over 40 years old have weak regeneration capacity after transplanting. To ensure their survival, maintenance and management of transplanted large spruce saplings is especially important.

As the taste of urban construction keeps improving, the scale and grade of urban greening and beautification also rise accordingly, requiring the greening and beautification effect to be shown within a relatively short time, so a considerable number of tall trees need to be transplanted. Hebei Saihanba Mechanical Forest Farm, as the largest larch timber forest base in North China, also shoulders the mission of windbreak, sand fixation and water conservation, and for many years has provided a large number of greening saplings to the Beijing-Tianjin region, with spruce as the main tree species in particular. Based on years of management experience and practice, the author offers the following humble views on the maintenance and management of large spruce sapling transplanting:

Transplanting large spruce saplings requires maintaining the metabolic balance of water in the tree body.

1. Moisture retention of the aboveground part

Trunk wrapping: Use straw rope, cattail bags, moss and other materials to tightly wrap the trunk and relatively thick branches. The above wrapping materials have a certain moisture-retaining and heat-insulating property. After trunk wrapping treatment, first, it can avoid direct strong light and dry wind attack, reducing water evaporation from the trunk and branches; second, it can store a certain amount of water, keeping the branches and trunk often moist; third, it can regulate the temperature of the branches and trunk, reducing damage to the branches and trunk from high and low temperatures, with good effect.

Water spraying: The aboveground part of the tree body (especially the leaf surface) easily loses water due to transpiration, so water must be sprayed in time to retain moisture. Water spraying should be fine and even, reaching all aboveground parts and the surrounding space, providing a moist microclimate environment for the tree body. High-pressure water guns can be used for spraying, or a water supply pipe can be installed above the tree crown, with one or several fine-hole nozzles installed according to the size of the crown for spraying, which has good effect but costs more labor and materials.

Shading: In the early stage after transplanting large spruce saplings or in hot and dry seasons, a shade shed should be built for shading, to lower the temperature inside the shed and reduce water evaporation from the tree body. In areas planted in rows, in patches, and with relatively high density, large sheds are suitable, saving materials and making management convenient; solitary trees are suitable for individual sheds per plant. Full-crown shading is required, and the top and surroundings of the shade shed should keep a distance of about 50 cm from the tree crown, to ensure a certain air flow space inside the shed and prevent sunscald damage to the crown. The shading degree is about 70%, allowing the tree body to receive a certain amount of scattered light to ensure photosynthesis of the tree body. Later, depending on tree growth and seasonal changes, gradually remove the shading materials.

2. Promoting new root growth

(1) Water control

Strictly control the amount of soil watering. At transplanting, water thoroughly the first time, and afterward water cautiously according to weather conditions and soil texture.

Prevent water accumulation in the tree pit. The watering hole left at planting should be filled level or slightly higher than the surrounding ground after the first thorough watering, to prevent water accumulation when it rains or when watering. At the same time, in low-lying places prone to water accumulation, drainage ditches should be opened to ensure timely drainage on rainy days.

Protect new buds. The sprouting of new buds is a sign of the physiological activity of spruce and the hope for spruce survival. More importantly, the sprouting of the aboveground part of the tree body has a natural and effective stimulating effect on the root system, promoting root sprouting. At the same time, after the tree body sprouts, maintenance work such as water spraying, shading, and disease and pest control should be especially strengthened to ensure the normal growth of tender buds and tender shoots.

Soil aeration. Do a good job of intertillage and loosening the soil to prevent soil compaction. Frequently check the soil aeration facilities. If aeration facilities are found to be blocked or waterlogged, remove them in time, so as to often maintain good aeration performance.

(2) Tree body protection

Support: Big trees attract wind. After transplanting, large spruce saplings should be supported and fixed immediately, carefully preventing them from toppling. An equilateral triangular stake is most conducive to tree body stability; the support point is best at about 2/3 of the tree height, and a protective layer should be added as padding to prevent bark injury.

Disease and pest control: Adhere to prevention first; according to tree species characteristics and the occurrence and development patterns of diseases and pests, check frequently and do good prevention work. Once disease occurs, apply the right remedy and control it in time.

Fertilization: Fertilization helps restore tree vigor. In the early stage after transplanting large spruce saplings, the root system has low fertilizer absorption capacity, so extra-root topdressing is suitable, generally about once every half a month. Use quick-acting fertilizers such as urea, ammonium sulfate, and potassium dihydrogen phosphate to prepare a fertilizer solution with a concentration of 0.5% to 1%, and choose morning, evening, or cloudy days for foliar spraying; if rain occurs, spray once again. After the root system sprouts, soil fertilization can be carried out, requiring light fertilizer applied frequently, carefully preventing root injury.

Freeze protection: The shoots and root system of newly planted large spruce saplings sprout late, the annual growth cycle is short, and the nutrients accumulated are few, so the tissues are not plump and are susceptible to low-temperature damage; freeze protection and heat preservation work should be done well.

After autumn begins, control nitrogen fertilizer, increase phosphorus and potassium fertilizer, and gradually extend the light duration and increase light intensity, to improve the lignification degree of the tree body and improve its own cold resistance.

The maintenance methods and maintenance priorities for newly planted large spruce saplings should be flexibly applied according to time, place, and tree, because of differences in environmental conditions, seasons, and tree bodies, so as to achieve the expected results.