Maidenhair Tree

Basic Information
Tree ID: 
141
Family: 
Ginkgoaceae
Genus and species: 
Gingko bilboa
Description: 
Ginkgo biloba, also known as the maidenhair tree, is considered one of the oldest plants on Earth. This tree is native to China and is often looked at as “living fossil” since it is the last living species of the Gingkoales, an order which appeared over 290 million years ago. The actual maidenhair tree appeared later, almost 180 million years ago during the Jurassic period. These large trees reach heights of up to 50m in China, but in North America, their average height is between 20 and 35m. As a large, deeply rooted tree, the maidenhair is very resistant to extreme weather changes, making it the perfect tree to be planted between Yale Health and Science Hill. The tree watches over the stressed students rushing to Science Hill and it greets the hospital’s daily visitors, rain or shine.
Surveyors: 
JoJo Gum & Sarah Mafroud
Location
Area: 
Prospect and Sachem
Collected Data
Tree shape: 
Pyramidal
Date of tree entry: 
02/16/2022
Height: 
10.10 m
Diameter at breast height: 
0.21 m

Bark
The maidenhair tree’s bark experiences many changes in its lifetime. Younger trees have lighter-coloured bark that is soft and weak. As the trees grow taller and older, this light wood becomes darker in color. This grayish bark is described as having shallow furrows and a corky texture. Over time, these furrows become deeper and the brown tones in the bark will give way to a more uniform ash gray. The image taken to the left is an example of an older gingko tree.
Twigs & branches
The ginkgo tree is pyramidal in its shape, with its branches growing sparingly upwards. The branches of these trees contain small, fan-shaped leaves that grow on short shoots. A plant shoot is a plant stem that is held together with its appendages, leaves and lateral buds. The ginkgo shoots are very short, and the leaves that grow on these short shoots are usually spaced out, experiencing very little growth in their first years. Upon second-year growth, the leaves appear clustered and reproductive structures begin to appear. The branches are grayish brown in color and smooth, without the ridges characteristic of the bark.
Reproductive Structures
Ginkgo ovules are fertilized by swimming sperm during germination in which the pollen grains release the sperm towards the ovules. The Ginkgo as a Gymnosperms do not have fruit but its seed does resemble a fruit. This is because the seed contains a fleshy outer seed coat.
Seasons
  • Ginkgo Tree in the Summer. Image courtesy of Martha Stewart.
  • Ginkgo Tree in the Fall. Image courtesy of Charlotte Creek Nursery.
  • Ginkgo Tree in the Winter. Image courtesy of Texas Tech University.
  • Ginkgo Tree in the Spring. Image courtesy of The Spruce.
Research
Natural range of distribution: 
Habitat: 
The Ginkgo tree is incredibly hardy and has the ability to survive in a wide variety of environments. This ability to survive has made them popular choices in cities due to its ability to thrive in the face of pollution, fungus, insects, drought, and smog. These traits among others have made it very popular in city planting including it becoming the most widely planted tree in New York City. Generally the habitat of Ginkgo trees is a a temperate climate. These trees prefer areas with access to lots of sunlight and moist soil. Additionally, Ginkgo roots can grow to be very long, therefore they prefer areas with deep soil however can tolerate a variety of soils such as sandy, loamy, and clay. While drought tolerant, these trees prefer a regular schedule of several inches of water per week in soils with good drainage.
Origin, history, and uses: 

Ginkgo biloba is one of the oldest plants in the world, originating in China almost 180 million years ago. Fossil evidence suggests that the tree has remained unchanged since the Jurassic period. The fossils of the maidenhair leaves show that the leaves are almost identical to the ones today, thus the reason why it is called a “living fossil.” 

Although the maidenhair tree is native to China and has been cultivated in China, Japan, and Korea since the 14th century. In 1690, there is record of Europeans coming into contact with the ginkgo in Japanese temple gardens. Nearly 100 years later, the tree arrived in the United States in 1784 thanks to England settlers who first planted the tree in Philadelphia, Pennsylvania. Despite its presence in the North American region for over 200 years, the ginkgo tree never actually naturalized. 

The ginkgo has many uses, across many different fields. For one, this tree has been used in traditional Chinese medicine for years. The Ginkgo seeds, leaves, and nuts have been used to treat dementia, asthma, bronchitis, and kidney and bladder disorders. Ginkgo extract is used in some countries because it is believed to enhance memory. Despite this, there is no conclusive evidence to support that the ginkgo is actually helping in treating or preventing any of these conditions. 

Unfortunately, the use of ginkgo extract and supplements can come with some side effects. The side effects include internal bleeding, nausea, vomiting, diarrhea, headaches, dizziness, and heart palpitations. It is not recommended to mix certain medications with ginkgo supplements, as they do not interact well. 

The ginkgo tree is not only used for medicinal purposes. In fact, the tree is very popular for landscape use and is popularly planted along streets and parking lots. Here at Yale, this tree is planted alongside the street leadings to Yale Health and can even be found in some parking lots. The shape and seasonal color of this tree makes it a popular choice, but it is often found that male trees are preferred because female trees grow bad smelling fruits. 

 
Phenology: 
The phenology of the Ginkgo tree is highly variable based upon the location of the plant as well as the climate in which it resides. Because of this variability extensive research has been conducted to determine the many changes to the phenology of Ginkgo trees caused by climate change. In Japan wind pollination occurred from the end of April to early May. This lead to fertilization in September. Contrastingly in Illinois pollination was observed in early May with fertilization occurring in early September. On average the time between pollination and fertilization was 133 days. Fertilization in general occurs while the seed remains attached to the tree. Temperature plays a large role also in the time of germination as seeds placed in warm greenhouses germinated nearly three times as fast as seeds in cool greenhouses. This dependence on temperature the timeline for germination extends to the inhibition of development and germination until the following spring or summer if the termperatures remain low (between two and ten degrees Celsius).
References: 

  1. Del Tredici, P. 1981. The Ginkgo in America. Arnoldia 51(2):150-161.

  2. Del Tredici, P. 1991. Ginkgo and People – a Thousand Years of Interaction. Arnoldia 51(2): 2-15.

  3. Del Tredici, P. 2000. The Evolution, ecology, and cultivation of Ginkgo biloba, pp. 7-23. In: T. A. Van Beek (ed.). Ginkgo biloba. Edition 1. Harwood Academic Publishers, Amsterdam.

  4. Gilman, E. 1997. Trees for Urban and Suburban Landscapes. Delmar Pub., Albany, NY
  5. Tredici, P. 2007. The Phenology of Sexual Reproduction in Ginkgo biloba: Ecological and Evolutionary Implications. https://doi.org/10.1663/0006-8101(2007)73[267:TPOSRI]2.0.CO;2
  6. https://www.gardenguides.com/122984-ginkgo-tree-habitat.html
  7. https://www.ediblewildfood.com/ginkgo.aspx