What are the characteristics of the ginkgo tree? A clear explanation in one article with the latest analysis
The branches and trunk of the ginkgo are tall and straight. The bark is shallowly fissured and light gray when young. As the tree ages, both the fissures and the color gradually deepen. The shape and length of the fissures differ noticeably from tree to tree. They range from linear to intersecting forms, with lengths varying from 40 cm to 100 cm.
Seed-grown ginkgo can exceed 30 m in height and over 3 m in diameter at breast height. Under suitable conditions, ginkgo can grow into high-quality timber with a straight, full trunk and a small taper. A suitable ecological environment is the foundation for ensuring that ginkgo grows into high-quality timber with a small taper. The ginkgo on West Tianmu Mountain in Lin'an County, Zhejiang Province, one of the places of origin, grows alongside tall trees such as golden larch, and because the mountain humus soil is loose and fertile, the plants grow more vigorously, with straight trunks; from the ground up, there is at least a dozen meters of trunk that is almost uniformly thick from top to bottom. A 90-year-old mature tree is 23-26 m tall, with a single-tree volume of about 1 cubic meter, and is still in the peak period of volume growth.
In ginkgo trees in an isolated state, as well as those distributed farther north (such as Liaoning) or farther south (such as Guangdong), the height of branching on the main trunk is generally less than 2 m, and the main trunk differs greatly in thickness from top to bottom, especially above and below the scaffold branches, where the difference is even more pronounced. This is the result of the plant's growth being inhibited by various factors. Nearly whorled scaffold branches can sometimes greatly inhibit the growth of the main trunk. Although this situation is extremely unfavorable for producing high-quality timber, it is favorable for the plant's flowering and fruiting.
The xylem of ginkgo is composed of circular tracheids with bordered pits. Some parenchyma cells contain large calcium oxalate crystals, which appear red; the rays are extremely undeveloped, and the annual rings are obvious. The cortex of ginkgo is relatively thick, with small diamond-shaped or oval lenticels, and the outer bark generally cracks in strips or small blocks, with varying degrees of intersecting.
There are a large number of latent buds on the main trunk of ginkgo. The short shoots sprouting from these latent buds can sometimes also flower and fruit. Under certain conditions, these latent buds also develop and swell, forming rows of tumor-like protrusions. At the base of the main branches or at the bends of large branches, these protrusions are stalactite-shaped and are commonly known as “ruzi”, “yinru” or “shuru”. The largest tree ru seen has a length of more than 2.0 m and a basal diameter greater than 28 cm (Guizhou). At the base of the trunk, these protrusions expand laterally, forming tumor-like growths that people call “chairs”. Sometimes rows of laterally arranged wart-like protrusions can be seen on the main trunk, which are also developed from the adventitious buds of ginkgo. Unlike tree ru, they show no obvious gravitropism. The mechanism producing these protrusions is not yet clear, and it is preliminarily inferred that it may be related to inhibited plant growth.
Both female and male ginkgo trees can produce tree ru, but the proportion of female trees producing tree ru is significantly higher than that of male trees. Therefore, among the people there is a saying that “ginkgo can only bear fruit after it has grown tree ru and chairs”. In fact, not only can large trees grow tree ru, but even one- or two-year-old seedlings, or even sprouted seedlings just two months after sowing, can also grow small tumor-like growths below the root crown when root growth is obstructed or under other specific conditions; conversely, not every adult ginkgo that has entered the fruiting stage can grow tree ru. Therefore, the statement that the formation of tree ru serves as a sign of entering the fruiting stage lacks a basis. Whether early identification of ginkgo fruiting and even other traits can be made based on the ease of producing tree ru is also worth further study.