-
If you are citizen of an European Union member nation, you may not use this service unless you are at least 16 years old.
-
You already know Dokkio is an AI-powered assistant to organize & manage your digital files & messages. Very soon, Dokkio will support Outlook as well as One Drive. Check it out today!
|
Flecher, S - Ficus benghalensis
Page history
last edited
by PBworks 16 years, 1 month ago
Ficus Benghanlensis
Banyan tree, Bengal fig, Indian fig, East Indian fig
Sara Flecher
This exotic tree species from the family of Moraceae is known for its bizarre, yet spectacular growth form and large overall size, its ingenious means of reproduction by means of a mutual relationship, and its great contributions to culture. I was interested in researching the banyan because it is so obviously unique, both aesthetically and physiologically.
The banyan has a unique germination capability. After being dispersed by fruit-eating birds and bats, the sticky seeds from the syconia fruit may fall to the ground and germinate in the soil like ‘conventional’ trees, or they may germinate high on the moist branches of rain forest trees. After germinating on tree tops, the banyan grows as an epiphyte sending numerous aerial roots down to the ground, wrapping tightly around its host tree on the way down (Strangers and Banyans, 2007). Through strangulation and/or shading of the host tree, the banyan kills the host tree and stands in its place. The network of aerial roots may also fuse together (anastomose) to form a massive woody envelope surrounding the host trunk (The Stranger Fig, 2007). With all of its many serpentine aerial roots along with its perennial life cycle, the banyan has immense growth potential. The Guinness Book of World Records has one individual recorded as the world’s largest tree crown, with 1,000 prop roots that covers an area of four acres (Strangers and Banyan, 2007). This expanding ability gives the banyan great significance in different cultures. It is considered sacred in the Hindu religion, as it represents eternal life because of its seemingly never-ending expansion. It is also found pictured on the coat of arms of Indonesia, representing one country with many “far-flung roots”(Laman, 1995).
The banyan twig has paired stipules or a circular stipule scar if the stipules have fallen off. The lateral veins at the base of the leaf are steep, forming a tighter angle with the midrib than the other lateral veins (“tri-veined”). The leaves are rough, hairy on the top side, large and singlular (Edwards, 1994). Also, the banyan has a white to yellowish sap that is excreted (latex). Natural rubber was identified for the first time in the latex of the F. benghalensis. The rubber content of this specie’s sap is approximately 17%, and has been considered a potential new rubber source (Natural rubber biosynthesis, 2000).
In addition to its unique growth form, the banyan has a very specific mutual relationship with the fig wasp in order to reproduce. The F. benghalensis has its own pollinator wasp species that only enters their syconia (the round fruit, enclosed inflorescence, of the banyan found in axillary pairs; approximately the size of a cherry). The small, scale-covered opening in which they enter is known as an ostiole (Strangers and Banyans, 2007). The syncoium has hundreds of tiny, pollen-bearing male flowers, seed-bearing female flowers, and gall flowers (sterile female flowers) lining the inside. The female fig wasp lays its eggs inside the ovaries of the short-style female flowers. When the wasps are born, they exit the syconia (covered in pollen) and make their way to the next syconia to repeat the process of laying eggs (Laman, 1995). Without the transferring of pollen from one syncoium to another by the fig wasp, it is impossible for the F. benghalensis to reproduce. This specific one-on-one relationship is considered by scientists to be a prime example of coevolution, as they found the tree and the wasp to mature at the same rate over time (Newbery, 1994).
The banyan is native to the tropical regions of Bangladesh, India, and Sri Lanka. The Indio-Malayan region in which it lives is suitable for this species’s very high moisture needs. According to the WWF, the banyan is found in tropical and subtropical moist broadleaf forests. In addition to its viability in tropical rainforests, the banyan can survive in less moist areas due to its drought resistance and ability to withstand mild frosts. Because of this, it has been able to be introduced into regions in Australia, Tanzania, Fiji, Colombia, and the US (Florida and Hawaii). It was first planted in the US by Thomas Edison in Fort Myers, Florida, where it is now known to be invasive (The Stranger Fig, updated 2007). The banyan is notorious for strangling orange and grapefruit trees. It also does damage to manmade structures. Seedlings germinate readily in the cracks and crevices of old buildings and then send aerial roots down the walls to the ground, pressuring some walls to crumble away. Also, their ever-exploring roots plug drainage and sewer lines and crack sidewalks (The Stranger Fig, updated 2007). The banyan is sometimes considered invasive, but it is a vital species in its native habitat and also is very useful to the human population.
The banyan has vast uses in its natural ecological environment. In spite of their nickname, the “strangler fig”, the banyan is an integral part of its ecosystem, acting as a keystone resource species. It feeds a variety of birds during the day and bats during the night. As a perennial C4 plant, its fruits are often in ample supply, typically producing three or more crops of fruit a year (Edwards, 1994). Also, hundreds of animals (such as frogs, lizards, beetles, and geckos) make their home in the hollow trunk where the tree has enveloped the decayed host tree. Human use includes shade for large areas, timber for furniture, making paper pulp, and treating inflammations, vomiting, and ulcers (Tuck-Po, 2003). The banyan tree is indispensable, beautifully exotic, and one of the most specific and unique trees on the planet.
IMG 2:An example of the colorful syconia of a T. benghalensis in Karnataka, India. IMG 3:This map shows the countries where F. benghalensis can be found.
It is native only to Banladesh, India, and Sri Lanka (in green),
but has been introduced into a variety of other areas, including
the US ( Florida and Hawaii), Tanzania, Australia, Colombia,
and a variety of southeast asain countries (in red).
Tropical and Subtropical Moist Broadleaf Forests
IMG 4:A picture of the clear-cutting method of deforestation in Peru.
Tropical and subtropical moist broadleaf forests are characterized by low variability in annual temperature and high levels of rainfall (>200 centimeter annually). These forests are generally found in large patches centered on the equatorial belt and between the Tropics of Cancer and Capricorn. These forests are particularly found in the Indo-Malayan Archipelagos, the Amazon Basin and the African Congo (Laurence 2006). The Ficus benghalensis is native to Indomalaya forests (which includes parts of the Indian subcontinent and Southeast Asia) (Laman 1995). Scientists have concluded that although this biome only accounts for 6% of the world’s terrestrial area, up to half of the world’s species may live in these forests (Edwards 1999). The very wet and perpetually warm climate allows more explosive plant growth than in any other environment (Laurence 2006). Because of the year-round rainfall, the soil is thin and nutrient poor. This is result of the soil’s old age (up to 100 million years), the washing away of minerals from the rain, and the extensive exposure to heat that turns soil into red clay. The topsoil tends to be only 2.5 to 5 centimeters deep. Biodiversity is so great in this biome because the plants themselves have adapted to storing the nutrients in themselves, rather than getting them from the soil (Edwards 1994).
Tropical and subtropical moist broadleaf forests are known for being one of the most threatened biome on the earth. Human activity and usage has created significant, irreversible damages to these tropical forests and continue to do so. Activities known to contribute to these drastic amounts of deforestation include “subsistence activities (on a local level), oil extraction, mining, logging, war, commercial agriculture, cattle ranching, hydroelectric projects, pollution, hunting and poaching, the collection of fuel wood and building material, and road construction” (Laurence 2006). Commercial forest destruction is often a result of developing countries with outstanding debts. The rise in population is also a key factor in deforestation, whether it is by cattle ranching or subsistence farming (Achmaliadi 2002). Monocrops, usually consisting of tropical hardwoods (mahogany, teak, ebony), rubber, oil, palm, chocolate, and fruit that are grown for profit also contribute to the damage done. Not only are large areas of forest cleared for agricultural purposes, but pesticides, herbicides, and fertilizers are often used. These chemicals have long-term effects on the soil and water of the area (Laurence 2006). Those partaking in these destructive activities seem to only focus on the short term economic advantages created without considering the long-term damage being done. The factor that is immeasurable is the cost benefit that is being given up. The prices for tropical timber woods (although an $8 billion a year industry) and other goods derived from rainforest destruction do not reflect the full environmental costs of the loss of goods and services provided by the ecosystem (Newbery, 1999). The fragmentation of the ecoregion has a huge effect alone. Many animals will not travel far when their habitat is discontinuous. More importantly, pollinators may not travel to reach other areas of the forest. For example, the deep-forest euglossine bee species will not cross a clearing of 100-meters, thus isolating bees as well as the orchids that they pollinate. This limits the diversity of both species by dividing the gene pool (Laurence 2006). The deforestation and development that has been occurring has increased natural extinction rates by 1000 times (Tuck-Po 2003). Prior to modern human influence, these forests are said to cover approximately 16 million square kilometers. Today about 8 million remain intact. The rate of forest loss is an astounding 1 million square kilometers every 5-10 years. This rate is said to accelerate. Deforestation and species extinction has a nonlinear relationship. Initial destruction will affect only those species that have highly restricted ranges while driving some species into shrinking remnants of their original territory. When these remnants become smaller and fewer between, extinction rates will accelerate with great speed (Laurence, 2006). Tropical and subtropical moist broadleaf forests are also susceptible to natural threats. These threats include fires, droughts, tropical storms, and volcanic activity (Edwards, 1994). Although these abiotic factors are considered threatening, they may occasionally be beneficial to an ecosystem. For example, a forest fire has the effect of clearing the forest floor and weaker trees, thus allowing new growth (Newbery, 1999). In the long-run, these natural threats have always been present and are part of a natural cycle and are not nearly as influential as the threat caused by mankind.
There are many things that can and should be done in order to preserve this fragile biome. There is a large amount of people who believe that forest reserves are the answer to this problem. Although it is wonderful to be able to set aside sections of tropical forests by law, it is unreasonable to think that tropical forests cannot be cut altogether. It is more logical to look for a way that they can be cut in an ecologically sound manner opposed to being cleared for poor-quality farmland or wasted by poor harvest practices (Tuck-Po, 2003). Forest regeneration methods of cutting, such as selection or shelterwood systems allow the forest to keep its ecological integrity (Laurence, 2006). Political action can also be taken. A good example is the Tropical Forest Conservation Act (TFCA). It was enacted in 1998 to offer the option to developing countries of being relieved of certain debts owed to the US while at the same time generating funds to support local tropical forest conservation activities. Involved countries in this program include Bangladesh, Belize, El Salvador, Panama, Peru, and the Philippines (Tuck-Po, 2003). More compromises between countries, such as this one, will decrease the economic dependency on deforestation of some countries. One of the best things that can be done is to bring together researchers, policy analysts, and practitioners together in order to integrate many independent conservation activities taking place (Tuck-Po, 2003). This will bring much more adaptive management of tropical forests.
IMG 5:This graph denotes the major causes of deforestation. IMG 6:Map with biome geographic distrubution.
Bibliography
Achmaliadi, Restu. 2002. The State of the Forest: Indonesia. Bogor (Indonesia): World Resource Institute. p. 23-47, 59-66.
Earle, Olive L. 1967. The Strangler Fig and Other Strange Plants. New York (NY): William Morrow and Company. p.1-12.
Edwards, David S. 1994. A Tropical Rainforest: The nature of biodiversity in Borneo at Belalong, Brunei. Singapore: Sun Tree Publishing. p. 136-140.
Laman, Tim. 1995. Borneo’s Strangler Fig Trees. National Geographic: 38-55.
Laurance, William F. 2006. Emerging Threats to Tropical Forests. Chicago (IL): The University of Chicago Press. p. 15-67.
Newbery, D.M. 1999. Chages and Disturbance in Tropical Rainforest in South-East Asia. London (UK): Imperial College Press. p. 59-79.
Stranglers and Banyans: Amazing Figs of the Tropical Rain Forest. Wayne’s Word Natural History [Internet]. [updated 2007] [cited 2007 Feb 17] 8:30. Available from: http://waynesword.palomar.edu/ploct99.htm
Tuck-Po, Lye. 2003. The Political Ecology of Tropical Forests in Southeast Asia, Historical Perspectives. Victoria, (Australia): Trans Pacific Press. p. 1-71.
Bibliography: Images
Image 4: http://images.encarta.msn.com/wrefmedia/sharemed/targets/images/pho/t012/T012558A.jpg
Flecher, S - Ficus benghalensis
|
Tip: To turn text into a link, highlight the text, then click on a page or file from the list above.
|
|
|
|
|
Comments (0)
You don't have permission to comment on this page.