Why trees need salmon

I found this article very enlightening. If you are interested in reading this study click here. Filed under: Uncategorized. You are commenting using your WordPress.

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Create a free website or blog at WordPress. WP Designer. Tonyaswenor's Blog. Side-by-side with salmon, Sitka spruce Picea sitchensis , for example, take 86 years, rather than their usual to reach 50 cm thick.

One might even infer past salmon populations from the nitrogen in tree rings, Naiman believes. Salmon, in turn, need big trees. They clean and shade the water, helping eggs to survive. And strong currents cannot shift their heavy debris, leaving small fish somewhere to hide. Studies of fish-eating animals had shown that salmon transport marine nitrogen upstream, says freshwater ecologist Alan Hildrew, of Queen Mary and Westfield College, London, UK.

Its effect on trees is another piece of the picture. But, he adds, from a study of only two rivers it is difficult to know whether nutrients from salmon make the land around the river more fertile, or whether more fertile rivers attract salmon.

This page has been archived and is no longer updated Jump to main content Jump to navigation nature. Search Advanced search. One study concludes that trees on the banks of salmon-stocked rivers grow more than three times faster than their counterparts along salmon-free rivers and, growing side by side with salmon, Sitka spruce take 86 years, rather the usual years, to reach 50 cm thick. Scientists have long known that nitrogen content in a tree can be measured from its growth rings, and several research projects explore the link between nitrogen, tree rings and the size of past salmon runs.

Using an increment borer, researchers extract small pencil-shaped samples of wood from the cores of ancient trees. The cross section of growth rings in core samples is then measured to determine nitrogen content.

Sources of soluble nitrogen, as are found in sap residues, are removed to ensure an accurate determination of marine-derived nitrogen at the time of ring formation. Using a combination of streams with mature trees and years of known salmon escapement — the number of salmon that return to spawn — scientists found historical fluctuations in nitrogen levels taken from the yearly growth rings of trees show a positive correlation with the known number of salmon returning to spawn the previous year.

Using tree rings to reconstruct historic salmon returns for the many watersheds where mature streamside trees still exist but escapement records do not, may become a valuable tool.

And as salmon runs around the world fluctuate or disappear, ancient trees may help us unlock secrets of the past to manage fisheries for the future.

Bears often drag their catch onto stream banks or into forest edges to eat, and once they consume the oily roe, belly, brain and skin, the rest of the carcass is left untouched and available to other animals, like insects and small mammals. As leaching by rain and microbial activity break down carcasses even further, nutrients become available to plants in the riparian zone. And just as trees need salmon, salmon depend on trees. Every part of a tree participates in enriching a stream for aquatic life, from its tiny needles to its strong twisted roots.

Streamside vegetation shades spawning streams, keeping developing eggs cool. The leaves and needles of streamside plants house terrestrial invertebrates which fall into the water and feed growing young salmon. Tree roots stabilize stream banks to slow erosion and protect the clean water salmon need to survive.