Each growing season in the life of a tree leaves its mark in the ring of a layer of cells formed in the trunk that conduct water and minerals from the roots to other parts of the plant.
The growth rings are visible because of differences in the density of the wood produced early in the growing season and that produced late in the season. The early wood has large cells with thin walls; late wood has smaller cells with thicker walls.
Within a given growth layer, the change from early wood to late wood is gradual but a clear change is visible where the small thick-walled cells meet the larger thin-walled cells of the next growing season.
The thickness of the yearly growth layer will vary from year to year. The amount of light, rainfall, temperature, amount of soil water and the number of frost-free days all play their part in altering the appearance of each layer. The width of the growth layer is a fairly accurate indicator of the amount of rainfall in any particular year. If conditions are good and there is ample water the growth rings are wide if water is scarce the rings are narrow.
In arid regions, such as the tundra where the growing season may be only a week or two long the growth rings are almost too close together to count. Some trees in this area may be two feet high and a hundred years old.
Each growth ring is different and a study of the rings tells the story of the area that could go back several centuries. In a year when fire ravaged a forest the event will be recorded in the charred rings. Which side of the tree received the most heat will show as a dip in the yearly rings.
The closer the rings are together the shorter the growing season. Counting the rings will give a fairly accurate time when the event occurred.
Western White Pines are very large trees, 150 feet (50 m) high and 5 feet (150cm) in diameter and will live up to 400 years. When the growth rings of these trees are studied with modern measuring devices they reveal a great deal about the yearly climate conditions on our west coast.
Information provided by growth rings of both evergreens and deciduous trees is being used to reconstruct past weather conditions and to predict future conditions. With more accurate knowledge of past climate conditions, which may go back hundreds of years, than is provided by human records which go back only a few centuries, it will be possible to determine weather patterns and cycles for rainfall and drought. This knowledge will be used to manage and allocate the resource of the future, fresh water.
Speaking of Nature
Jim Ferguson, 5313 River Road, R.R.5, Renfrew, Ontario K7V 3Z8 Phone 613-432-2738 email jamesh@nrtco.net
The growth rings are visible because of differences in the density of the wood produced early in the growing season and that produced late in the season. The early wood has large cells with thin walls; late wood has smaller cells with thicker walls.
Within a given growth layer, the change from early wood to late wood is gradual but a clear change is visible where the small thick-walled cells meet the larger thin-walled cells of the next growing season.
The thickness of the yearly growth layer will vary from year to year. The amount of light, rainfall, temperature, amount of soil water and the number of frost-free days all play their part in altering the appearance of each layer. The width of the growth layer is a fairly accurate indicator of the amount of rainfall in any particular year. If conditions are good and there is ample water the growth rings are wide if water is scarce the rings are narrow.
In arid regions, such as the tundra where the growing season may be only a week or two long the growth rings are almost too close together to count. Some trees in this area may be two feet high and a hundred years old.
Each growth ring is different and a study of the rings tells the story of the area that could go back several centuries. In a year when fire ravaged a forest the event will be recorded in the charred rings. Which side of the tree received the most heat will show as a dip in the yearly rings.
The closer the rings are together the shorter the growing season. Counting the rings will give a fairly accurate time when the event occurred.
Western White Pines are very large trees, 150 feet (50 m) high and 5 feet (150cm) in diameter and will live up to 400 years. When the growth rings of these trees are studied with modern measuring devices they reveal a great deal about the yearly climate conditions on our west coast.
Information provided by growth rings of both evergreens and deciduous trees is being used to reconstruct past weather conditions and to predict future conditions. With more accurate knowledge of past climate conditions, which may go back hundreds of years, than is provided by human records which go back only a few centuries, it will be possible to determine weather patterns and cycles for rainfall and drought. This knowledge will be used to manage and allocate the resource of the future, fresh water.
Speaking of Nature
Jim Ferguson, 5313 River Road, R.R.5, Renfrew, Ontario K7V 3Z8 Phone 613-432-2738 email jamesh@nrtco.net
No comments:
Post a Comment