[Smart Farmers] This unique "small ingot" in China is a favorite "dessert station" for migratory birds

In the cold winter, what do resident birds (as opposed to migratory birds) that live in the north all year round rely on to make a living? The main food of resident birds is the fruits and seeds left on plants, but flowing water is not easy to find in the cold winter.

But don't worry, the wonderful nature has already prepared a "water reservoir" for the birds in winter, and it is filled with "energy drinks" that can keep out the cold. This "water reservoir" is the Acer truncatum.

The maple tree is rich in sap. In winter, birds only need to peck holes in the tree trunk to get sap to quench their thirst. The maple tree also has an advantage in that its sap contains sugar, which is richer in calcium, magnesium, organic acids and vitamins than other sugars. It can improve nutritional imbalances and is a timely help for birds in winter.

China's unique "small ingot"

Acer truncatum is a unique tree species in my country, widely distributed in northern provinces and regions. Its leaves grow in pairs on both sides of the branches, with 3 to 5 corners on the edges and a flat base, so Acer truncatum is also called flat base maple.

The base of the Acer truncatum leaf is truncated (Photo by Bai Ruixing)

The flowers of the maple are small and yellow-green, and the flowers and leaves bloom together in April. When the fruits are ripe in August and September, you will find countless small "ingots" hanging on the tree - this is because the fruit of the maple has a thin and flat "small wing" on each side. The wings are rectangular, slightly longer than the core, and the two wings open at an obtuse angle; the wing fruit is light green when tender, and light yellow or light brown when ripe, and the shape is very similar to the ancient Chinese "gold ingots", and the name of the maple comes from this.

Flowers of Acer truncatum (Photo by Bai Ruixing)

The green young fruits of Acer truncatum (Photo by Bai Ruixing)

After mid-autumn in October, the leaves of the Acer truncatum turn yellow, purple, orange-red, or bright red. It is a famous tree species with colorful leaves in autumn in northern China.

A large number of maple trees and other autumn-colored trees are planted in Beijing's Old Summer Palace. When the autumn breeze blows, the beautiful scenery of the forests painted in red colors vividly depicts the distinct seasonal changes in the north. Qianlong once wrote a poem praising "Thousands of red leaves in the forest are like a brocade", "Looking at the maple and cypress today, the autumn color is half red and yellow", and "The green willows and red maples paint the garden scenery". The "maple" in his poem does not refer to a specific tree species, but a general term for maple trees such as maple, red maple, and five-pointed maple.

The scenery of the yellowing leaves of the Acer truncatum in autumn (Photo by Bai Ruixing)

The scenery of the maple tree's leaves turning orange and red in autumn (Photo by Bai Ruixing)

The scenery of the maple tree's leaves turning bright red in autumn (Photo by Bai Ruixing)

How to cultivate and apply Acer truncatum?

Acer truncatum is produced in the temperate climate zone in northern my country. It is afraid of high temperature and exposure but likes a sunny environment. It is not suitable to be introduced to the south. It can withstand low temperatures of around -25 degrees Celsius and is drought-resistant, but it is afraid of waterlogging. It is best not to plant it near streams and other water bodies.

In addition, the Acer truncatum is not tall among the trees. It grows mixed with white birch, poplar and other trees in the acidic soil mountainous areas in North China at an altitude of 1,000 to 1,800 meters, and is often used as the understory tree of mixed forests.

In terms of greening applications, Acer truncatum also plays an important role. It has a beautiful tree shape, rich shade, and golden or bright red autumn leaves, which are very pleasing to the eye. It is particularly suitable for garden beautification and landscape forest planting. In addition, Acer truncatum has a well-developed root system, which is very suitable for making root-lifting bonsai.

The well-developed root system also makes the Acer truncatum highly resistant to winds. In addition, it can grow in all kinds of soils, has strong resistance to toxic gases such as sulfur dioxide and hydrogen fluoride, and has a strong ability to adsorb road dust. Therefore, it has high ecological benefits and has become an excellent shelterbelt tree species. It can be used for greening windproof areas and industrial and mining areas.

Acer truncatum has a hundred treasures hidden in its body

In addition to being used for beautification and greening, Acer truncatum also has many "treasures" hidden in it, playing an important role in various fields.

New resource high quality edible oil

The seeds of Acer truncatum are large, the oil content of the kernel can reach 48%, and the oil yield by machine pressing is 35%, which is higher than that of rapeseed.

Acer truncatum seed oil has a delicate and fragrant taste and is a semi-drying oil rich in a variety of essential fatty acids for the human body. The content of unsaturated fatty acids is as high as 92%, and the content of essential fatty acids is as high as 53%. The oil is of excellent quality and has extremely high health-care effects. It is rare among edible vegetable oils.

Acer truncatum seed oil is rich in fat-soluble vitamins and high in vitamin E, so it has good antioxidant properties and is particularly resistant to storage and not easy to become rancid or deteriorate.

An ideal and high-quality new protein resource

In addition to extracting oil, the seeds of Acer truncatum can also be eaten directly. In ancient my country, people in many regions had the habit of frying and eating Acer truncatum seeds, which tasted similar to melon seeds.

According to measurements, the protein content of Acer truncatum kernels is 25% to 27%, including 9 essential amino acids for the human body. It does not contain starch and is a complete protein, which is rare among plant seeds.

The food produced from it is of excellent quality, delicious and of high nutritional value. The oil residue extracted from the seed kernel is also a good edible protein and can be used to make high-quality soy sauce.

Good wood for making special tools

The wood of the maple tree is tough and fine, and can be used to make various special tools such as vehicles. It is also an excellent material for construction, furniture, carving, and joinery. Its bark fiber can also be used to make paper and produce substitute cotton.

New resource of high-quality active tannins

One of the uses of tannin is tanning leather. The tannin content of Acer truncatum seed coat is 60%, which is a condensed tannin.

Currently, most condensed tannins at home and abroad come from bark and roots and can only be obtained by cutting, while tannins from the seed coat of Acer truncatum can be regenerated every year.

Honey Source

Although the corolla of the Acer truncatum is small and pale in color, it contains nectar glands. In addition, when it blooms in late spring, there are so many flowers that they attract bees to collect and make nectar, making it an excellent nectar plant.

Nectary

Nectaries in the flowers of Acer truncatum (Photo by Bai Ruixing)

In short, Acer truncatum is an excellent economic tree species with multiple uses. It is listed as a key tree species for the construction of national ecological reserve forests and the development of woody oil crops. It is suitable for large-scale promotion and cultivation in various provinces in North China.

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

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

Editor: Xie Yun