Key Points of the Film-Wrapping Regeneration Technique After Bark Peeling of Eucommia ulmoides

1. Peeling cycle. Mastering the peeling cycle has practical significance for increasing the per-unit-time bark yield and economic benefits of Eucommia ulmoides. From the perspective of short-term benefits, the shorter the peeling cycle, the greater the bark yield, but the regenerated bark will become increasingly thinner, and at the same time the tree vigor will be noticeably weakened, and the bark-producing life of the tree will be relatively shortened. Therefore, considering overall benefits, the peeling cycle of Eucommia ulmoides should be relatively longer, with once every 3 years being appropriate.

2. Peeling time. Eucommia ulmoides can be peeled from April to September during the growing season, with May to July giving the best results. Peeling should preferably be carried out on cloudy days or after 4 p.m. on sunny days when the temperature is 25-35°C and the relative humidity is above 80%. Be careful not to peel on rainy days.

3. Preparation before peeling. In places with good irrigation conditions, the Eucommia ulmoides tree can be watered thoroughly once 1 week before peeling; in places where watering is not possible, it is best to seize the time and peel after a thorough rain. Select middle-aged trees (over 8 years old) with vigorous growth, dense branches and leaves, and a trunk diameter of more than 6 cm as the peeling targets. Before peeling, prepare a peeling knife (either a budding knife or an electrician's knife will do), transparent film, and tying rope.

4. Peeling method. Take the section from 10 cm below the first branch of the main trunk to 10 cm above the ground as the peeling section. The method is to first make a horizontal cut with the knife tip angled downward 45° at 10 cm below the first branch of the main trunk, then make another horizontal cut with the knife tip angled upward 45° at 10 cm above the ground. Then make a longitudinal cut, deep enough to reach 3/4 of the phloem, being careful not to injure the xylem, and then use the back of the knife to gently lift the bark and tear it to both sides with the knife until only a strip of bark about 10 cm wide remains in the peeling section. The remaining bark strip helps transport nutrients. Note that throughout the entire peeling operation, hands and tools must not injure or contaminate the peeled surface.

5. Management after peeling. (1) Immediately after peeling, spray the peeled surface with a "High-Efficiency Tree Bark Growth Promoter" solution at a concentration of one part per one hundred thousand, then wrap the peeled surface with plastic film, tying the upper part tightly to prevent rainwater seepage, and the lower part slightly loosely. (2) After 40 days, untie the wrapping and expose the peeled surface. For isolated trees and trees at the forest edge, after untying the wrapping, pay attention to shading and preventing exposure to the sun.

6. Simple processing of the bark. Spread out the peeled bark with the inner bark facing each other in pairs, stack them together, press flat and compact, cover with rice straw, and let it sweat. After 1 week, the inner bark turns purplish brown; take it out and dry it in the air.