white-barked pine

white-barked pine

Pinus bungeana (scientific name: < ipinus bungeana < / I Zucc.) is a pine tree belonging to the family Pinaceae, with a height of up to 30 meters and a diameter at breast height of up to 3 meters. It has an obvious trunk, slender branches, obliquely spreading, tower shaped or umbrella shaped crown. Its winter buds are reddish brown, oval, and no resin. There are stomatal lines on both sides of the leaf back and ventral surface, with sharp apex and serrate margin. Male cones are ovoid or oval, cones are usually solitary, light green before maturity, yellowish brown at maturity, seeds are grayish brown, nearly obovate, reddish brown, flowering from April to may, cones mature from October to November in the next year.

It is an endemic tree species to China. It is distributed in Shanxi, western Henan, Qinling Mountains in Shaanxi, southern Gansu and Maiji Mountain in Tianshui, Guanwu mountain in Jiangyou, northern Sichuan and Western Hubei. It is cultivated in Suzhou, Hangzhou and Hengyang. It grows in the area of 500-1800 meters above sea level. It grows well on calcareous soil and loess with warm and cool climate, deep soil layer and rich soil.

The heartwood is yellowish brown, the sapwood is yellowish white or yellowish brown, the texture is straight, glossy, the pattern is beautiful, the proportion is 0.46. It can be used for building, furniture, stationery and other materials; the seeds are edible; the trees are beautiful with white or brown and white bark. It is an excellent garden tree species.

(Overview) source: China National Herbarium

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morphological character

Tree, up to 30 meters high, diameter at breast height up to 3 meters; has obvious trunk, or several trunks from the trunk near the base; the branches are slender and oblique, forming a wide tower to umbrella shaped crown; the bark of young trees is smooth, gray green, and falls off into irregular thin pieces after growing up, exposing new yellowish green bark; the bark of old trees is light brown gray or gray white, and splits into irregular scaly pieces, After abscission, it is nearly smooth, showing pink white endodermis, white and brown alternating into spot scale; annual branches are gray green, glabrous; winter buds are reddish brown, oval, without resin. The needles are thick and hard, 5-10 cm long, 1.5-2 mm in diameter, with stomatal lines on both sides of the back and abdomen, apex pointed, and margin serrate; the transverse section is fan-shaped triangle or wide spindle, with single subcutaneous layer cells, occasionally 1-2 intermittently distributed second layer cells on the back, resin channels 6-7, marginal, sparse, and 1-2 middle ones on the back corner; the leaf sheaths fall off. Male cones ovoid or elliptic, about 1 cm long, mostly clustered at the base of new branches, 5-10 cm long.

Cones usually solitary, erect at the beginning, drooping at the end, pale green before maturity, yellowish brown at maturity, ovoid or conic ovoid, 5-7 cm long, 4-6 cm in diameter, short stemmed or almost sessile; seed scales oblong, broadly cuneate, apex thick, scale shield subrhombic, with transverse ridge, scale umbilicus in the center of scale shield, obvious, triangular, with spines at the top, spines pointed downward, sparse spines not curved The seed is grayish brown, nearly obovate, about 1 cm long, 5-6 mm in diameter, the seed wing is short, reddish brown, the nodes are easy to fall off, about 5 mm in length; the cotyledons are 9-11, needle shaped, 3.1-3.7 cm long, about 1 mm in width, the primary leaves are narrow strip, 1.8-4 cm long, less than 1 mm in width, with stomatal lines above and below, and serrate margin. The flowering period is from April to may, and the cones mature from October to November the next year.

Habitat of producing area

Pinus bungeana is an endemic tree species in China. It is distributed in Shanxi (Luliang Mountain, Zhongtiao Mountain and Taihang Mountain), western Henan, Qinling Mountain in Shaanxi, southern Gansu and Maiji Mountain in Tianshui, Guanwu mountain in Jiangyou in northern Sichuan and Western Hubei. It is cultivated in Suzhou, Hangzhou and Hengyang. Born in 500-1800 meters above sea level.

Growth habit

It grows well on calcareous soil and loess with warm and cool climate, deep soil layer and rich soil.

It is slightly resistant to shade when it is young. Deep rooted, long life, up to hundreds of years. It grows best on calcareous soil or loess with deep, moist and fertile soil layer. The growth temperature range is - 30 ℃ - 40 ℃, and it can adapt to the low temperature of - 30 ℃ and pH value of 7.5-8. It can not grow well under the condition of high temperature and high humidity, and can not grow in the place of poor drainage or ponding. It has strong resistance to sulfur dioxide and smoke pollution and grows slowly.

Methods of reproduction

sow

Pinus bungeana is usually propagated by sowing, and the sandy loam with good drainage, flat terrain and deep soil layer should be selected as the nursery ground. Sowing immediately after thawing in early spring can reduce Damping off of pine seedlings. Because of the fear of waterlogging, high bed sowing should be adopted. Sufficient bottom water should be poured before sowing. About 1 kg seeds per 10 square meters can produce 1000 to 2000 seedlings. After sowing, covering soil 1 to 1.5cm and covering with plastic film can improve the germination rate. After the seedlings are fully grown, gradually increase the ventilation time, so as to remove all the film. After sowing, the seedlings were unearthed with shells and fell off on their own in about 20 days. During this period, bird damage should be prevented. The seedling stage should be covered with shelter to prevent sunburn, and the soil should be buried to prevent cold before winter. The main roots of seedlings are long and the lateral roots are few, so the lateral roots should be less damaged when transplanting, otherwise it is easy to die.

grafting

If the softwood grafting is adopted, the softwood of Pinus bungeana should be grafted onto the older stock of Pinus tabulaeformis. The survival rate of Pinus bungeana twigs grafted on 3-4-year-old Pinus tabulaeformis rootstock can reach 85% to 95%, with strong affinity and fast growth. The scion should choose the new shoot with strong growth, and its thickness should be 0.5cm.

When transplanting bare roots of two-year-old seedlings, it is necessary to protect the roots and avoid the damage of root drying. It should be planted as soon as it is dug, and then it should be transferred every few years to promote the growth of fibrous roots and facilitate the survival of planting. Generally, more than 10-year-old seedlings are used for greening. The best transplanting time is dormancy in early winter and freezing in early spring. When transplanting big seedlings, they must be transplanted with soil balls. When planting big seedlings with DBH less than 12 cm, it is necessary to dig a soil ball with height of 120 cm and diameter of 150 cm, wrap it with straw rope, prevent the soil balls from breaking during transportation, and erect piles to bind and fix it after planting.

cultivation techniques

Land selection and preparation

The seedling of Pinus bungeana should be well selected for fear of waterlogging, and the seedling field should be flat with drainage and irrigation conditions. Heavy clay soil, saline alkali soil and low-lying waterlogged land should not be used as nursery land. Fine soil preparation, seedling field should be deep turned, leveled, harrow fine, apply enough base fertilizer, such as rotten manure, compost. Calcium superphosphate can also be mixed with cake fertilizer or soil miscellaneous fertilizer, and the effect is better. Before soil preparation, 10 kg ferrous sulfate powder per mu was sprayed and turned into the soil for sterilization. After the land is prepared, it will be made into a north-south border field with a ridge height of 25 cm and a width of 1 m for sowing.

Seedling management

After the seedlings were fully grown, the ventilation time of seedbed was gradually increased, and the resistance was enhanced by refining seedlings. Pinus bungeana likes light, but the seedlings are shade tolerant. After removing the film, the shade net should be covered immediately to prevent the damage of high temperature sunburn and Rhizoctonia solani.

Fertilize and water

Long drought without rain or high temperature in summer should be watered in time. Weeding should master the principles of early weeding, small weeding and clean weeding. Weeding between plants should be done by hand to prevent damage to seedlings. After sowing seedlings and pulling grass, the soil should be properly covered to prevent cracks. Weeding and soil loosening were combined for drill seeding, and thinning and replanting were carried out at the same time. After that, the water should be drained in time.

Base fertilizer should be the main fertilizer for Pinus bungeana seedlings, and topdressing should be the supplement. From the middle of May to the end of July, topdressing should be carried out for 2 to 3 times, mainly with nitrogen fertilizer. Top dressing should be done with 3 draughts of rotten human manure or pig manure per mu, about 20 draughts of water, 5 to 15 kg of rotten cake fertilizer per mu, about 15 draughts of cake fertilizer and water, and about 4 kg of urea per mu. In the late growth stage, nitrogen fertilizer should be stopped and phosphorus and potassium fertilizer should be increased to promote the lignification of seedlings. 0.3% to 0.5% potassium dihydrogen phosphate solution can also be sprayed on the leaves.

Pinus bungeana seedlings grow slowly and should be planted closely. If it is necessary to continue to cultivate large seedlings, it should be transplanted 2 to 3 times before planting. The two-year-old seedlings can be transplanted with soil before the apical buds sprout in early spring. The spacing between plants and rows is 20-60 cm, and the apical buds are not damaged. After planting, the seedlings can be watered twice, and then 6-7 days later. 4-5-year-old seedlings can be transplanted with soil ball for the second time, and the spacing between plants and rows is 60-120 cm. After survival, the soil around the roots should be kept loose. Each tree should be applied with 100-120 kg of decomposed organic fertilizer. After burying the soil, it should be watered. After that, the management should be strengthened to promote growth and cultivate strong seedlings.

Pest control

Pine aphid

Damage characteristics: the adult is black, the egg changes from dark green to black, and the egg overwinters on pine needles. The weak aphid hatches in early April and damages the base of pine needles. The most serious damage period of songdaya is from the middle of April to the middle of May. The adult of Aphis matsutake sucks the sap of trees, which can cause coal pollution. 1-2-year-old twigs and saplings are the main targets of Aphis matsutake, which can cause the decline and death of trees.

Prevention and control measures: first of all, tending management, especially young forest, cutting off the eggs and leaves in winter, burning intensively to eliminate the source of insects. After the middle of March, we can spray 2.5% permethrin EC 5000 times (or 40% Omethoate EC 1000 times) to inhibit egg hatching. The best control period was from early April, spraying 10% imidacloprid 1000-1500 times or 50% dimethoate 1000 times in 10 days

Chinese PinYin : Bai Pi Song