Detailed Explanation of Key Techniques for Transplanting Large Red Spruce (Picea koraiensis) Trees

Red spruce, also known as Tiger-tail Pine, Korean Spruce, etc., is an evergreen tree of the genus Picea in the family Pinaceae. It is native to Northeast China and Korea, and is now widely planted in the Beijing and Qingdao areas, with some distribution in the Northwest as well. This tree species has a graceful form, with a spire-shaped crown and large branches that spread horizontally or extend slightly at an angle; it is highly adaptable, with a shallow root system and well-developed lateral roots, making it relatively easy to survive after transplanting.

I. Transplanting Time

Spring is the best time for transplanting large trees. Under complete technical measures, transplanting in late November and late May can both achieve a survival rate of over 98%.

II. Transplanting Preparation

1. Planting hole: Based on the size of the root ball of the tree to be planted, increase the hole diameter by 40 to 100 cm beyond the root ball dimensions and deepen it by 20 to 40 cm. The planting soil should preferably be neutral to slightly acidic soil rich in organic matter; poor soil should be improved.

2. Seedling standards: It is best to select nursery stock that is robust, full in tree form, and free of pests, diseases, and mechanical damage.

3. Before digging up the seedling, spray the crown with an antitranspirant and properly tie up the crown with straw rope. Clear away the rootless topsoil and leaf litter. With the trunk as the center, draw a circle with a radius 4 to 5 times the trunk diameter, and dig vertically downward from outside the line until reaching the root ball height; use a shovel to smooth the shoulder of the root ball, gradually tapering inward to half the root ball height so that the root ball takes a flattened spherical shape; cut small roots with a sharp shovel, and use a saw or shears for thick roots to avoid shaking the root ball apart.

4. After the root ball is lifted, wrap, bind, and package it with pre-moistened straw rope. Extra-large root balls can be packaged in wooden crates and set aside for transport.

III. Planting

1. Before planting, backfill the planting soil so that the center is slightly higher than the surroundings. The backfill height should be such that after the root ball is placed, it sits 5 cm below the ground surface.

2. Planting: Gently place the seedling's root ball into the tree hole, straighten the tree, adjust the main viewing side, remove the packaging, then readjust the tree body, and backfill the planting soil in layers and firm it down; set up tree supports.

3. Watering: After planting, build a water-retaining berm with soil. The berm must be large enough and tamped firm to prevent water leakage. Water thoroughly 3 times within one week of planting, with the first watering within 24 hours after planting. After watering, promptly check the supports; if the tree is leaning or the supports are loose, straighten and reinforce them in time.

IV. Maintenance

Based on weather conditions and soil moisture, replenish water in a timely manner. For transplanting in midsummer, apply water to the foliage; regularly apply foliar fertilizer; during windy and rainy weather, check promptly, and if the tree is leaning or the supports are loose, straighten and reinforce the supports in time; regularly spray pesticides to prevent the occurrence of pests and diseases.