The Latest Planting Techniques and Methods Tutorial for Tree of Heaven

Tree of Heaven is also known as Ailanthus bark, large-fruited tree of heaven, etc. It is a tree plant of the genus Ailanthus in the family Simaroubaceae. Its trunk is straight and tall, and its crown is rounded like a hemisphere, quite spectacular. Its leaves are large and its shade is dense, and in autumn red fruits cover the tree. Although the leaves and flowers have a slight odor when blooming, it is not serious, so it is still a very good ornamental tree and shade tree. Now let us take a look at the planting techniques for Tree of Heaven!

Ecological Habits of Tree of Heaven

Tree of Heaven likes light and does not tolerate shade. It has strong adaptability. Except for clay, it can grow in various soils and neutral, acidic, and alkaline soils. It is suitable for deep, fertile, moist sandy soil. It is cold-tolerant, drought-tolerant, and not tolerant of waterlogging. Long-term water accumulation will cause root rot and death. It has a deep root system, is relatively resistant to smoke, dust, and sulfur dioxide, and has few pests and diseases. In China, it is distributed everywhere except Heilongjiang, Jilin, Xinjiang, Qinghai, Ningxia, Gansu, and Hainan, and it is widely cultivated around the world.

Propagation Techniques for Tree of Heaven

Tree of Heaven is generally propagated by sowing. When the samaras mature, cut them off together with the small branches, dry them in the sun, remove impurities, and store them dry. The germination capacity can be maintained for 2 years. Before sowing, soak the seeds in 40°C warm water for one day and one night, which can advance germination by 5-6 days. The sowing rate is 5-8 kg per mu, with row spacing of 25-40 cm for drilling, covering with soil 1-1.5 cm, and the germination rate can reach 85%. The suitable temperature for seed germination is 9-15°C, and sowing is generally carried out from early March to late April. One-year-old seedlings can reach 60-100 cm in height, with ground diameter of 0.5-1.5 cm. In addition, it can also be propagated by suckers and root cuttings. For large seedlings used as street trees, the trunk is required to be straight and the branching point high. Generally, stumping can be carried out in the second spring of seedling cultivation, and then lateral buds should be removed in time so that the trunk continues to extend. After reaching the desired trunk height, lateral branches are allowed to develop to form the crown. Spring transplanting should be carried out when the strong buds on the upper part of the seedling expand into a spherical shape, and it should be planted appropriately deep.

Planting Techniques for Tree of Heaven

1. Seedling afforestation: Planting can be done in both spring and autumn. The key is to grasp the suitable timing and deep planting. Spring afforestation should be planted early, when the strong buds on the upper part of the seedling stem enlarge and become spherical. The planting depth should preferably exceed the root collar by 2-3 cm. On hillsides, level trenches or fish-scale pits can be used for site preparation. Where there are no uneven areas, hole-shaped site preparation is mostly used. The planting density should not be too large. The usual spacing between plants and rows is 1×2 m. The root holes are 40 cm long, wide, and deep each. In dry and windy places, stumping afforestation is suitable. In early spring, bury to a depth exceeding the root collar by 15-18 cm, with the upper end level with the soil surface or exposed 1 cm above the surface.

2. Direct sowing afforestation: For direct sowing afforestation, sites on shady slopes and semi-shady slopes have a higher survival rate. The afforestation time is carried out in the three seasons of spring, rainy season, and autumn. Spring sowing generally emerges in the rainy season. Seeds that have not undergone pregermination treatment are likely to survive. For spring sowing emerging in the rainy season, although the aboveground part may dry up and die in winter, strong shoots can still sprout from the root collar the following spring. For reverse-slope fish-scale pits, dig a trench near the outer edge parallel to the outer edge. In the inner trench and outer platform method, dig a trench on the outer platform and sow. The trench width is 5-6 cm, the trench depth is 3 cm, and 40-50 seeds are sown per trench, covered with soil 1.5-2.0 cm, and lightly compacted. The sowing rate is 0.5 kg per mu.

3. Tending and management: After afforestation of Tree of Heaven, stump once each autumn or spring within 1-2 years. In that year, the tree height can reach 2-3 m. In April-May, select and retain one strong sprout, and carry out bud removal and tending year after year. When the tree height reaches the required height, stop removing buds, so that height growth gradually weakens and diameter growth at breast height is promoted. In the third year of direct sowing afforestation, the derived young plants compete for light and nutrients. To ensure the rapid growth of superior plants, weak seedlings must be removed as early as possible. Generally, where site conditions are good, seedlings grow quickly, so thinning should be earlier and more intensive; conversely, thinning should be later and less intensive.

4. Pest and disease control

① Ailanthus silkworm moth: In winter and spring, look for cocoons on treetops and trunks to destroy pupae. Inspect insect feces under the tree and damaged symptoms on the tree, and when larvae are found, manually shake the branches to hunt and kill them. During the larval stage, spray for control with 20% Mie Saoli emulsifiable concentrate 2000 times solution, 2.5% Kung Fu emulsifiable concentrate 2000 times solution, 2.5% Di Haishai emulsifiable concentrate 2000 times solution, etc. Use light traps to kill adults.

② Spotted lanternfly: In cold winter, scrape off egg masses on the trunks. In pure forests with severe damage, build mixed forests. Protect and utilize natural enemies such as parasitic wasps of the lanternfly. For adults and nymphs, spray with 20% phosphamidon emulsifiable concentrate 1500-2000 times, or 50% monocrotophos water-soluble agent 2000-3000 times, or 50% phoxim emulsifiable concentrate 2000 times, or 40% dimethoate emulsifiable concentrate 1500-2000 times solution.