<p>Depending on the fauna within the rivers and lakes, submerged trees can be like reefs in oceans. They provide protection for fish and other fauna and they can also act as nurseries for certain types of fish.</p>

<p>Submerged trees can sometimes be snags in waterways which increases the difficulty in navigating waterways, particularly for larger boats.</p>

CC BY-SA 3.0
2017-11-13T23:59:57.390Z
Thanks for your answer, is there any other ways it benefits the river/lake and is detrimental to humans?
mt12345
CC BY-SA 3.0
2017-11-13T23:54:52.207Z
2017-11-13T23:54:52.207Z
Fred
<p>Ecosystem benefits of submerged trees include providing growth locations and nutrients for algae, phytoplankton, molusks, and other organisms. They can provide, not only protection for fauna, but shading for refuge from heat. They can increase eddies and areas of low flow that can be beneficial for fish and other fauna. Some species take advantage of pools formed behind downed trees in streams. </p>

<p>They can increase sedimentation by trapping sediments or decreasing flow and this can have a negative impact on species that require a gravel stream bed. They can increase flooding which may have positive or negative impacts on people and the ecosystem.</p>

<p>Snags in waterways are an issue for large boats, restricting access or causing damage in collisions, as mentioned in another answer. But they can also be deadly to small boats like kayaks and canoes. The water flows through the limbs of downed trees and the surprisingly strong hydraulic pressure can trap boaters underwater in these "strainers". This can happen with stream current or tidal flow.</p>

CC BY-SA 3.0
2017-11-14T04:28:06.177Z
2017-11-14T04:28:06.177Z
haresfur
<p>In the following questions I am wondering how large woody debris and/or submerged trees enhance river or lake environments.  Also I am wondering how they are detrimental to humans. </p>

<p>I know that large woody debris and submerged trees are commonly found in rivers and lakes. They may be present by a result of flooding, logging, bank erosion, forest fires, beavers and many other causes.</p>

<p>I am not sure how they would enhance river or lake environments.  Clearly beavers could use them to build dams but how is this good? Is there any other ways they benefit?  </p>

<p>Also, how are they detrimental to humans?  Might they potentially hurt the ecosystem present in the water, which in turn may hurt humans if they are using the ecosystem for resources? </p>

CC BY-SA 3.0
2017-11-13T22:07:20.410Z
This might be more suited for biology.SE. It certainly isn't on topic here.
bon
CC BY-SA 3.0
2017-11-13T22:18:33.913Z
Even it's detrimental influnce on humans?
mt12345
CC BY-SA 3.0
2017-11-14T03:24:50.323Z
@jeopardytempest thanks for the edit! Do you have any possible answers for my questions?
mt12345
CC BY-SA 3.0
2017-11-14T05:53:02.667Z
Afraid not, have never done much in biology/hydrology. Just didn't feel it was fully off-topic here. I'm not sure what the best spot is for its chances at an answer... maybe biology, though nowhere is perfect unfortunately. But if it doesn't do well here, voters may indicate where it should go... or you can request it be moved (but please wait, rather than ask the same question at Biology!) I just felt your question was reasonable enough that it should be cleaned up in hopes someone else may be able to answer it.
JeopardyTempest
CC BY-SA 3.0
2017-11-14T05:53:05.643Z
If you have any context, it could help (is it related to homework... or something you've noticed... or what?)
JeopardyTempest
CC BY-SA 3.0
2017-11-14T07:08:03.310Z
If the question is split (positive/nagtive consequences) and narrowed down there are certainly sites for it. Just limit the question to biological or economic aspects.
Jan Doggen
CC BY-SA 3.0
2017-11-15T15:14:17.033Z
@mt12345 You might  this discussion concerning [cross posting](https://meta.stackexchange.com/questions/64068/is-cross-posting-a-question-on-multiple-stack-exchange-sites-permitted-if-the-que) of questions. It tends to draw negative attention (downvotes and closevotes) to your questions.
justCal
<rivers><lakes>
Results of large woody debris in river/lake
mt12345
# Results of large woody debris in river/lake

(Asked by: username_0 on 2017-11-13)

In the following questions I am wondering how large woody debris and/or submerged trees enhance river or lake environments. Also I am wondering how they are detrimental to humans.

I know that large woody debris and submerged trees are commonly found in rivers and lakes. They may be present by a result of flooding, logging, bank erosion, forest fires, beavers and many other causes.

I am not sure how they would enhance river or lake environments. Clearly beavers could use them to build dams but how is this good? Is there any other ways they benefit?

Also, how are they detrimental to humans? Might they potentially hurt the ecosystem present in the water, which in turn may hurt humans if they are using the ecosystem for resources?

**Tags:** rivers, lakes

> **Comments:**
> **username_1**: This might be more suited for biology.SE. It certainly isn't on topic here.  
> **username_0**: Even it's detrimental influnce on humans?  
> **username_0**: @username_2 thanks for the edit! Do you have any possible answers for my questions?  
> **username_2**: Afraid not, have never done much in biology/hydrology. Just didn't feel it was fully off-topic here. I'm not sure what the best spot is for its chances at an answer... maybe biology, though nowhere is perfect unfortunately. But if it doesn't do well here, voters may indicate where it should go... or you can request it be moved (but please wait, rather than ask the same question at Biology!) I just felt your question was reasonable enough that it should be cleaned up in hopes someone else may be able to answer it.  
> **username_2**: If you have any context, it could help (is it related to homework... or something you've noticed... or what?)  
> **username_3**: If the question is split (positive/nagtive consequences) and narrowed down there are certainly sites for it. Just limit the question to biological or economic aspects.  
> **username_4**: @username_0 You might  this discussion concerning [cross posting](https://meta.stackexchange.com/questions/64068/is-cross-posting-a-question-on-multiple-stack-exchange-sites-permitted-if-the-que) of questions. It tends to draw negative attention (downvotes and closevotes) to your questions.  

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## 2 answers

### Answer by username_5 on 2017-11-13. Score: 1

Depending on the fauna within the rivers and lakes, submerged trees can be like reefs in oceans. They provide protection for fish and other fauna and they can also act as nurseries for certain types of fish.

Submerged trees can sometimes be snags in waterways which increases the difficulty in navigating waterways, particularly for larger boats.

> **Comments:**
> **username_0**: Thanks for your answer, is there any other ways it benefits the river/lake and is detrimental to humans?  

---

### Answer by username_6 on 2017-11-14. Score: 1

Ecosystem benefits of submerged trees include providing growth locations and nutrients for algae, phytoplankton, molusks, and other organisms. They can provide, not only protection for fauna, but shading for refuge from heat. They can increase eddies and areas of low flow that can be beneficial for fish and other fauna. Some species take advantage of pools formed behind downed trees in streams.

They can increase sedimentation by trapping sediments or decreasing flow and this can have a negative impact on species that require a gravel stream bed. They can increase flooding which may have positive or negative impacts on people and the ecosystem.

Snags in waterways are an issue for large boats, restricting access or causing damage in collisions, as mentioned in another answer. But they can also be deadly to small boats like kayaks and canoes. The water flows through the limbs of downed trees and the surprisingly strong hydraulic pressure can trap boaters underwater in these "strainers". This can happen with stream current or tidal flow.


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