It stands at an incredible 84 metres tall and Some coastal redwoods have been known to be as old as 2, years old, and giant redwoods can live to over 3, years. One of the reasons redwoods live so long is due to a substance in their barks called tannin.
This increases the tree's resistance to pests and diseases, and helps to deter insects like termites. In their natural habitat, forest fires are common.
Redwoods have thick, spongy bark which is around 12 centimetres thick and can reach 1. This helps to protect them from flames, along with the water-based sap they produce. As redwoods grow, they lose their lower branches which stops fire spreading to the canopy. They have relatively few smaller relatives in their environment.
In fact, neither the coastal redwood nor the Sequoia have any close relatives in their environment. The coastal redwood and the Sequoia are the closest relatives of one another, but the natural range of the coastal redwood and Sequoia are not close to one another.
The coastal redwood's natural range is, as the name suggests, close to the coast. The Sequoia lives in the Sierra Nevada mountain range.
Their next closest relative, the dawn redwood, is in China, while the coastal redwood and Sequoia are mostly in California. In their natural range, the closest relatives of both trees diverged from their line in Mesozoic, the age of the dinosaurs, or earlier, probably more than a hundred million years ago.
Close Relatives Carry Dangerous Diseases But why is not having close relatives in your environment important? Close relatives frequently carry diseases and parasites that can infect one another. For example, one of our two closest relatives, the chimpanzee, shares all our communicable diseases and vice versa. The orangutans, also our close relatives, are in danger of extinction in part because they are dying from diseases they get from us.
White-tailed deer, the most numerous terrestrial mammal greater than a 50 kilograms, pounds, full grown, provide another example. The white-tailed deer carries a brain worm that can infect and is generally fatal to other deer, including the larger Moose, and Elk.
The white-tailed deer survives the brain worm, but other deer find it difficult to impossible live in the range of the white-tailed deer. This is because of the brain worm and several other diseases the white-tailed deer carries.
Relatives with Large Populations are Dangerous The larger a population is the more diseases it is likely to support. We humans are learning this as our population grows we are adding to the collection of communicable diseases that afflict us. On the other hand with a large population, it is more likely that some individual within that population will be immune.
This will allow that individual to survive and reproduce and through natural selection the whole population is likely to eventually have the immunity. So living in the range of a close relative that is numerous is a disadvantage, both because they are likely to have many dangerous diseases and because they are more likely to be immune to a disease that is deadly to you.
Smaller organisms are generally more numerous. This is true if we look at the population at any one instant in time, but it is even more true over time. There are likely to be more individuals of a species of mouse than a species of elephant.
But if we compare all the individual mice of one species living over the course of a century to the elephants that lived in that same century the difference is likely to be even more dramatic because the larger organism usually has a longer life span. As coastal redwoods and Sequoias can live for thousands of years they are a good example of this rule. If two similar groups of organisms compete, for example, marsupials and placental mammals, the one which is more fit will tend to take over the niche that has the most individuals.
There is no known insect that can destroy a redwood tree. Redwood heartwood is pale to dark reddish brown and the sapwood narrow and creamy. Texture is fine and usually even because there is little difference between the early wood and the late. The grain is straight and the wood is not resinous.
Sequoias and giant redwoods are often referred to interchangeably, though they are two very different, though equally remarkable, species of tree. Both naturally occurring only in California, these two species share a distinctive cinnamon-colored bark and the proclivity for growing to overwhelming heights.
The species of Sequoia which grows along the coast has been variously named. Perhaps the most important reason is that the oils in redwood give it natural weather resistance, and it lasts two or three times as long as Douglas fir outdoors.
They are cone-bearing seed plants with vascular tissue.
0コメント