Seed collection, seedling cultivation and afforestation techniques of spruce

Spruce is also known as Maxwell spruce, rough spruce, rough spruce. Its material is good, slightly soft, flexible, easy to process, with the production of high-quality building materials, furniture, pillars and other uses. Spruce is suitable for temperate humid climate and is one of the main timber tree species in North, Northwest and Southwest China.

1. Seed collection

In the northwest natural forest region, spruce seeds begin to mature in October, and the cones can be collected from green to yellowish brown and chestnut brown. It is best to choose 30-50-year-old plants with strong growth, excellent stem shape and no diseases and insect pests, but because of the large task of seed collection in natural forest areas, the method of purchasing seeds from forest farmers is often adopted, and seeds are collected from the established mother forest and seed orchard.

The recovered cones should be immediately scattered and dried in the seed farm, beaten and threshed with a stick, the sundries should be removed after wind selection, the pure seeds should be dried, put into sacks, placed in a cool, dry and ventilated storage room, and then transported or sown.

2. Raising seedlings

Spruce is the main tree species for site regeneration in its distribution area, and most of them cultivate seedlings in forest nursery or forest mountain nursery.

The main results are as follows: (1) the selection of nursery land should be located near or near the center of the nursery land, with convenient transportation and open terrain, and it is best to be located on flat land with good drainage or gentle slope land of 10: 30; soil texture is an important condition for nursery selection. Generally, sandy loam and light clay loam with high fertility are suitable. At the same time, it should be close to the water source to facilitate irrigation, and it is taboo to set up nurseries in places such as cold current collection, stagnant water depression, heavy saline-alkali land, closed light canyon, harmful wind outlet and so on.

(2) in the rainy season of the year before sowing, the weeds were ploughed once (20~25cm), and then turned and raked flat at the end of autumn, and the grass roots were picked out for bed in the following spring. Thaw in spring, immediately turn the ground to make a bed, generally rainy areas use high bed, bed height 15~20cm, bed width l.lm, long l0cm, trail 50cm, bed direction to north-south direction is appropriate, mainly to prevent summer seedlings from sunburn. Flat beds are used in areas with little rain. Disinfect the soil with raw lime water or ferrous sulfate 3-5 days before sowing. Turn it shallow and rake it flat and press it fine.

(3) Spruce is usually sown from mid-late March to the end of April, and can be unearthed in about half a month. In general, the seeds are not treated with germination, but only soaked in 0.5% copper sulfate solution for half an hour before sowing, and then sowed to dry to prevent root rot blight. Generally use strip sowing, with east-west direction as appropriate, strip width 10~12cm, strip spacing 10~20cm, cover soil thickness 0.5~1cm, cover soil preferably humus soil or sawdust in the forest, sowing amount of 20-25kg per mu; immediately after sowing, cover with grass or spread with bamboo curtain in the seedbed to shade, moisturize, heat preservation, avoid Rain Water drenching topsoil, so that soil hardening and erosion.

Spruce seedlings were raised in full light, sown with 30~50kg per mu, then covered with fine sand and coarse humus with a thickness of about 1cm, and finally suppressed. The sowing time of all-light seedlings is in late May, and the seedlings come out in early June, which can avoid the last late frost and the seedling preservation rate is high. Sprinkle water once a day after sowing, sprinkle water twice a day after the seedlings are unearthed, and make the soil of the seedling bed wet about 2cm each time. When spruce seedlings are raised in full light, many seedlings die after overwintering, mainly due to drought and windy in winter and spring, loss of balance of water above ground and underground, resulting in drought and death of growth. therefore, it is very important to inject enough winter water. The nursery bed should be watered several times at the end of autumn and the beginning of winter, and the last winter water should make the seedlings covered with a thin layer of 2cm ice. In this way, spruce seedlings will not die because of physiological drought after overwintering, which greatly improves the seedling preservation rate. Spruce planted widely and densely, there are many seedlings, and the annual seedlings are about 2 million per mu. The growth of seedlings is accelerated in the third year, so it is necessary to transplant and change beds, otherwise it will grow poorly because it is too dense. Transplantation is carried out in spring, generally 1 mu can be transplanted to 3 mu. When the 5-year-old seedlings came out of the nursery, the remaining bed seedlings produced about 150000 seedlings per mu, and the transplanted seedlings produced 10 ~ 150000 seedlings.

(4) in order to achieve the purpose of cultivating strong seedlings and high yield, the management of spruce should be strengthened after sowing, and the main items are shading, spraying, irrigation, loosening soil and weeding, cold prevention and so on.

Set up a shade to wait for the seedlings to come out, that is, pile and kidnap the bamboo curtain on the seedbed on the scaffolding, take the upper shade, and the shade leaves the ground 20~30cm, its transmittance is 25% 50% better.

Disease-proof spruce seedlings are easy to be infected with bacterial blight. Therefore, immediately after the seedlings are unearthed, spray 0.5% Bordeaux solution or 0.5% ferrous sulfate solution every 7-10 days for 2-3 months.

Weeding spruce seedlings within a year, tender and weak, weeding is a key link. As long as weeds are found on the seedling bed, they should be pulled out in time. Pull the grass thoroughly and at the same time protect the seedlings so as not to damage the root system.

To prevent cold, such as better management in summer, seedlings can be lignified in autumn, and it is easier to survive the winter, but they all need to be protected from cold in winter, that is, in the middle of November, take off the bamboo curtain and sprinkle it on the seedbed with wheat straw, and its thickness is appropriate to cover the seedlings. Then cover the bamboo curtain on the seedbed. In the middle and late March of the following year, when the weeds turn green, the curtain should be opened for 4 or 5 days before covering the grass. It is better to remove the grass late than early to prevent the spring cold.

The above is mainly one-year-old seedling management, the second year still needs shade, mainly irrigation, disease control, weeding, but two-year-old seedlings do not need cold protection, after the third year, the management is relatively extensive, can raise seedlings in full light, four to five years out of the nursery, 15-200000 seedlings per mu. With regard to fertilization, it is best to apply sufficient base fertilizer, calcium superphosphate, ash fertilizer and oil residue are suitable, and ammonium nitrate and ammonium sulfate are better topdressing.

3. Afforestation

The main results are as follows: (1) in the selection of forest land for spruce afforestation, we should first consider afforestation in the distribution area, and at the same time select the topographical position suitable for spruce growth to afforest in arid low mountain areas. Soil moisture and excessive light are important limiting factors for the survival and growth of spruce, so we should choose shady slope and semi-shady slope for afforestation, and if necessary, we can also afforest on sunny slope, but we should put forward higher requirements for afforestation technology. In order to cultivate fast-growing and high-yielding large-diameter wood, it should be mainly afforestation in the cutting land, burning site, forest glade, or for the transformation of secondary forest.

(2) to build a large area of pure spruce forest in terms of composition and density. In terms of artificial forest, there is no good ready-made experience in the mixing of spruce and other tree species, but in the transformation of low-cost forest, shrub forest and some poplar and birch forests, planting spruce is a great inspiration to the mixing problem, and it can be considered to mix with poplar and birch in conditional areas.

The planting density of spruce should vary with different site conditions. In low mountain areas, considering the trunk development and branching characteristics of spruce, as well as water conditions, the planting density should be higher, generally row spacing 1.2-1.5m, plant spacing 0.75~lm, 450-700 trees per mu; cutting site conditions are better, row spacing 1.5-2m, plant spacing up to 1m-1.5m, keeping more than 300trees per mu.

(3) the main afforestation method of spruce is planting seedlings, which can be planted in both spring and autumn, mainly in spring. In spring, in order to grab soil moisture and ensure timely afforestation, afforestation should be carried out in the order of low mountains, then high mountains, first outside the ditch, then in the ditch, first sunny slope, then shady slope.

Spruce seedlings can be planted with 4 ~ 5-year-old seedlings, and 3-year-old seedlings can be used if the seedlings grow very well. Generally, the seedlings with height 15~20cm, basal diameter above 0.3cm, developed root system, complete terminal bud and robust growth are required to go up the hill, and the survival rate is higher.

The method of planting seedlings generally adopts the method of hole planting, and the size of the hole should be adjusted according to local conditions. Generally, the soil preparation specification of cave surface is 40 × 40cm or 30 × 30cm, and the depth is 20~30cm. Planting should not be too deep, and it is required to exceed the original soil mark 2~3cm. In addition, narrow planting can also be adopted in the case of thicker soil layer, less gravel, good water conditions and soil preparation in advance, but the root system must be extended and the gap must be firm, which can also ensure the survival rate of afforestation.

4. Nurturing and management

The main contents of artificial afforestation and tending management of spruce are soil management and weeding. After planting in the same year, soil cultivation, seedling support and steadiness were carried out in late May or early June. A small area of weeding can be carried out in late July, only around the hole. It is not necessary to weed completely in case the seedlings are sunburned. It is generally nurtured continuously for 3 years, and the last two years are mainly loosening soil and weeding. However, in natural forest areas, the contradiction between forest and animal husbandry is the main contradiction, such as cutting land and burning land, forage grass grows luxuriantly after afforestation, cattle and sheep trample and destroy a large area of artificial forest, which seriously affects the survival rate of afforestation, so we should negotiate with local villages to properly solve the contradiction between forest and animal husbandry.