With the increase in population, expansion of clinical applications, and development of foreign trade, the demand for Magnolia officinalis (Hou Po) continues to grow. However, the reliance on wild resources for medicinal use has led to a drastic decrease in resources and a shrinking distribution area. Wild plants are now extremely rare.
1. Wild Resources of Magnolia officinalis
The southern part of Zhejiang province, particularly the city of Lishui, is the largest traditional production area of Magnolia officinalis in China. Before the 1960s, there were abundant wild Magnolia officinalis plants growing in valleys at elevations of 400-1200m, accounting for 40-60% of the total national production. From 1965 to 1969, the annual production of Magnolia officinalis was 513.6 tons. However, due to extensive afforestation of Chinese fir (Cunninghamia lanceolata) in the city, most of the areas where Magnolia officinalis used to grow were replaced by Chinese fir forests. As a result, the distribution area of Magnolia officinalis decreased significantly, and the production dropped rapidly. From 1970 to 1979, the average annual production of Magnolia officinalis was only 203.0 tons, which was only 39.5% of the production in the 1960s. In 1982, due to the worsening supply-demand contradiction, the purchase price of Magnolia officinalis increased from 0.84 yuan/kg to 1.52 yuan/kg. Local farmers almost completely dug up Magnolia officinalis trees with a diameter at breast height of more than 10cm. The purchase volume in that year reached 2234.0 tons, which was 7.4 times the average of the previous 17 years. The wild resources of Magnolia officinalis suffered from destructive exploitation. However, the situation became even worse in 1988 when the purchase price of Magnolia officinalis skyrocketed from 3.0 yuan/kg to 30-50 yuan/kg. As long as they could be peeled, the wild Magnolia officinalis and its sprouts were dug up.
Sichuan, Chongqing, and Hubei are the main production areas of Magnolia officinalis. They account for 20-30% of the total national production. For example, Wanzhou in Chongqing is a traditional main production area of Magnolia officinalis, and its Magnolia officinalis was of superior quality. It used to be a tribute to the imperial court, and in the early years of the founding of the People's Republic of China, several tens of tons of Magnolia officinalis were exported overseas every year. However, due to poor development and protection, there is no longer any Magnolia officinalis available for purchase. In the valleys of Mount Emei in Sichuan, there used to be a considerable number of wild Magnolia officinalis, but they have almost been completely harvested. The situation is similar in western Hubei, where the remaining few Magnolia officinalis trees are mostly in artificial forests with a diameter at breast height of less than 10cm. Local farmers say that before the 1970s, Magnolia officinalis was used as firewood and no one wanted the seeds, which were only worth 10 cents per fruit. Now, there is nowhere to buy them even if they are sold for 5 yuan each. This shows the extent of resource depletion in this region.
In summary, the wild resources of Magnolia officinalis are on the verge of depletion. Many traditional production areas have no more bark or flowers to harvest, and some excellent germplasm resources have already disappeared or are disappearing.
2. Development of Magnolia officinalis Cultivation
Large-scale cultivation of Magnolia officinalis began after 1971. Magnolia officinalis bases have been established in Jining, Zhejiang; Enshi, Hubei; Guanxian, Sichuan; and Tongdao, Hunan. However, the main purpose of traditional afforestation was to afforest barren mountains, and most people believed that Magnolia officinalis could be grown anywhere because it is a broad-leaved tree. Existing Magnolia officinalis forests generally suffer from improper site selection, excessive density, mixed varieties, and low yields.
Wufeng County in Hubei is one of the main Magnolia officinalis base counties in Hubei province. The Xiangdangping Medicinal Plant Field, affiliated with the county's medical department, has 30 hectares of artificial Magnolia officinalis forests distributed on slopes or hills. The fastest-growing 22-year-old Magnolia officinalis trees have an average diameter at breast height of 8.0-12.2cm and a height of 10.0-12.8m. The Changlinggang Medicinal Plant Field in Enshi, Hubei, is the largest Magnolia officinalis base in Hubei province. In the 1970s, more than 700,000 Magnolia officinalis trees were planted there, but only about 200,000 remain. Most of them are planted on hills with shallow soil and poor fertility. The 20-year-old Magnolia officinalis trees there are only 7-10m tall and have a diameter at breast height of less than 10cm.
Guanxian County (now Dujiangyan City) in Sichuan is the largest Magnolia officinalis base county in Sichuan province. According to the "Economic Botany Resources of Sichuan Province," there are 1060 hectares of Magnolia officinalis. However, on-site inspections and further verification by local medical and forestry departments revealed that the actual total area is for "Magnolia officinalis, Eucommia ulmoides, and Phellodendron amurense," three types of woody medicinal plants. The actual area of Magnolia officinalis is less than 200 hectares. The best-managed medicinal plant field in Guanxian County has the best-growing forest, with 27-year-old Magnolia officinalis trees having an average diameter at breast height of only 10.2cm and a maximum diameter of 16.5cm. Due to the use of the "cut the large, leave the small" method for selective thinning, most of the forest stands are of poor quality.
Since the 1970s, Jining has established a total of 2000 hectares of artificial Magnolia officinalis forests, making it the largest artificial Magnolia officinalis base county in China. However, due to impure varieties and improper site selection, less than one-third of the forests are growing well.
3. Strategies for the Development and Protection of Magnolia officinalis Resources
The wild germplasm resources of Magnolia officinalis should be protected and managed according to the law. The remaining wild Magnolia officinalis resources are extremely scarce. If left uncontrolled, they will become extinct in a few years. Therefore, it is necessary to strengthen the protection and management of wild Magnolia officinalis resources in accordance with the "Forest Law" and the "Regulations on the Protection of Wild Plants." The stripping and felling of wild Magnolia officinalis trees are strictly prohibited, and the mother trees should be well protected to promote natural regeneration. Plants in nature reserves and botanical gardens should be protected as germplasm resources.
Accelerating the cultivation of artificial Magnolia officinalis forests and expanding the area of artificial cultivation are fundamental guarantees for the protection and development of Magnolia officinalis resources. To establish a high-quality and efficient Magnolia officinalis base that meets the high requirements of "safety, effectiveness, controllability, and stability" for traditional Chinese medicine modernization and internationalization, it is necessary to formulate and implement management standards for the production of Magnolia officinalis medicinal materials, and vigorously promote genetic control, site control, density control, and intensive management.
