Candles are actually insect secretions? Uncovering the ancient tree "factory" that produced candles

Why is the wax in “烛” (candle) written with the character “虫” (insect) on the right? In fact, it is not derived from petroleum refining, but from the secretions of two insects. They are beeswax (yellow wax) secreted by bees and white wax secreted by white wax insects. This explains why wax is written with the character “虫” (insect) on the right. Of the two wax materials, white wax is more widely used. It is odorless, shiny, and crystalline. In addition to being used to make candles, it can also be used as medicine after being refined. It has the effects of promoting tissue regeneration, healing sores, stopping bleeding, relieving pain, and treating tracheitis. In addition, it can also be used as a lubricant and rust inhibitor in industry.

The love-hate relationship between ash trees and wax moths

White wax worms are parasitic insects. When they live in groups on the branches of certain trees in the Oleaceae family, their male larvae will secrete a lipid compound with special properties and surround the branches, which will hinder the photosynthesis and respiration of the trees, harm the growth of the trees, and even cause the death of the trees in severe cases. However, on the other hand, this lipid compound is exactly the white wax needed by many industries. Therefore, people often take the initiative to raise white wax worms to produce wax sources. The most suitable host plants for raising white wax worms are Ligustrum lucidum and Fraxinus chinensis. The former is suitable for raising seed worms, and the latter is most suitable for producing wax, which is also the origin of the name of the white ash tree.

Careful people will find a grayish white, soft, cotton-like substance on the branches of the ash tree after releasing the insects. This is the wax secreted by the ash insects. Carefully peel off a ball of this wax and put it in a preheated iron spoon. It will gradually melt into liquid; then cool it for a while, and it will condense into a translucent solid. Use this solid as a lubricant for door bolts or match it with a fuse for ignition. The effect is no different from commercially available oil wax. What's more amazing is that applying it to a bleeding wound can stop the bleeding immediately, with a magical effect similar to "Yunnan Baiyao".

China began to use the secretions of wax insects to make candles in the Song Dynasty. Compared with the beeswax used as the raw material for candles before the Song Dynasty, the large output and low price of wax insects made candles gradually become a civilian product and became popular.

Distinguishing Fraxinus chinensis from Fraxinus chinensis

As an ancient candle "factory", the white ash tree is widely distributed in the north and south of China, and its cultivation history is quite long. During the Ming and Qing Dynasties, white ash trees began to be widely cultivated throughout the country. It should be noted that the white ash tree is different from the foreign ash (Fraxinus pennsylvanica). Foreign ash, also known as American red ash, is native to North America and has been introduced to China for cultivation for a long time. It is also distributed throughout the country.

The common point between the two is that they are both tall deciduous trees of the same family and genus, and their leaves are large pinnate leaves that are opposite and more than 20 centimeters long. Pinnate leaves refer to a number of leaflets growing on a common petiole or rachis. The leaflets are arranged like feathers on both sides of the rachis. Each leaflet has a significantly separated base and sometimes has its own petiole, but there is no bud under the petiole (while a complete leaf must have a bud under the petiole). The number of leaflets of both trees is odd, which is called odd-pinnate leaves.

The compound leaves of Fraxinus chinensis (Photo by Bai Ruixing)

The compound leaves of the ash tree (Photo by Bai Ruixing)

Second, the flowers of both ash trees and Fraxinus chinensis are large panicles. Third, both trees have "wings" around their fruits. These thin wing-like appendages allow the fruits to fly in the wind after drying, and be carried far away from the mother tree, thereby increasing the probability of reproduction.

Although the ash tree and the foreign ash have many similarities, there are also some obvious differences. First, the compound leaves of the foreign ash have 7-9 leaflets, while the compound leaves of the ash tree have only 5-7 leaflets. Secondly, the bark of the ash tree can be used as medicine, and was called "Qinpi" in ancient times, while the bark of the foreign ash tree cannot be used for medicinal purposes. Finally, the most obvious difference between the two lies in the growth position of the inflorescence and infructescence. The inflorescence/infructescence of the ash tree grows in the axils of the current year's branches (green young branches), or the inflorescence/infructescence grows at the top of the branches; while the inflorescence/infructescence of the foreign ash grows in the axils of the previous year's branches (brown-gray old branches), or the inflorescence/infructescence grows from the middle of the branches.

The following two pictures show the fruit sequence of white wax:

(Photo by Bai Ruixing)

(Photo by Bai Ruixing)

The picture below shows the infructescence of the ash tree (Fraxinus chinensis):

World-famous Chinese wax

White wax is mainly produced in my country. The Chinese first began to breed white wax worms in the Han and Wei dynasties more than 1,700 years ago. From ancient times to the present, the trees for raising white wax worms are all white ash trees (Chinese white wax). Mount Emei is the hometown of Chinese white wax. Since the Tang Dynasty, the Emei white wax has been listed as a tribute to the court. Because of its unique therapeutic effect and non-toxic side effects, it has been used as a holy medicine for treating diseases by medical experts of all generations and recorded in medical books. Around the middle of the 19th century (during the Qianlong period of the Qing Dynasty), white wax was introduced to Europe and was called "Chinese wax" by the West. Subsequently, "Chinese wax" became a Chinese specialty product in China-Europe trade and a traditional export commodity in my country, enjoying a very high reputation in the international market. Today, white wax is still a traditional backbone industry in some rural areas in the Emei Mountain area, and the annual output of white wax accounts for about 70% of the national total.

In addition to producing ash, the ash tree is also an important high-quality timber species. Because its wood has straight grain, soft and tough texture, it can be used to make furniture and high-quality martial arts equipment, as well as weaving various utensils. In ancient China, ash rods were used as materials for making spears and sticks. The more famous "Shaolin stick" was made from ash trees.

In addition, the ash tree has a well-developed underground root system, strong germination ability, rapid growth, and is resistant to moisture, drought, and barrenness. It has a strong adaptability to soil and can even grow in slightly saline-alkali land. Therefore, the ash tree is an excellent tree species for windbreak, sand fixation, embankment and road protection. In the past Yellow River flooding areas, large tracts of ash forests built a "green Great Wall", successfully blocking the raging yellow sand wind outlets, and turning the two thousand acres of sandy wasteland surrounded by ash forests into fertile fields. Later, ash trees were introduced to the Xinjiang desert and the saline-alkali land on the Yellow Sea coast, both of which played a huge role in improving local environmental protection. In addition, the ash tree has the characteristics of resistance to smoke, sulfur dioxide and chlorine, which is very suitable for use as a greening and protection forest in industrial and mining plant areas.

In recent years, the country has advocated the development of garden cities. The ash tree, with its sturdy trunk, graceful posture, golden leaves in autumn, and strong and stretching branches after the leaves fall in winter, has become a good tree species for beautifying towns in both the north and the south.

Scientific review: Hu Dongmei, Senior Laboratory Technician, College of Biological Sciences and Technology, Beijing Forestry University

Author: Wang Jue, Associate Professor, Beijing Forestry University

Hand-drawn illustrations: Xia Xinyi, student of the Middle School Affiliated to University of Science and Technology Beijing

Editor: Wu Yuetong