[jaykim]

How much can the noise level actually be reduced if trees like Italian Cypress are planted in the garden boundary?

The house is located about 650 feet (200 meteres) away from the 4 lane(both way) road, whose speed limit is 45 miles. There are nothing but the few trees and a small structure like one room house between the road and the garden in the gentle hilly side. The garden is elevated about 50 feet to 70 feet above the road in the gentle slope.



The decibel of the noise when the cars are passing by is around 60(55 and above), when measured by the android app.

Can it be lowered by at least 5 decibel if the trees are planted around the perimeter?

If so, what kind of trees are the best and how tall should the tree be to have some meaningful reduction in the noise level?

Is there any other way to reduce the noise level?

Thank you very much.

 

[Cedrus]

It is going to be difficult to muffle the noise because you are higher than the road. What is your budget ? Are you under water/drought restrictions ? If possible, plant a solid line and another in back of the first line to fill in spaces. Maybe a third line of Photinia in front or back. How about a waterfall or two...... or three ?

 

[Nik333]

I think noise goes up, also. I'm sure you've seen the noise reduction walls next to the freeway in SoCal.


I lived in a nice housing development in Carlsbad, CA. We were at least 100 feet higher than the road and a mile away. The noise was still frightful at AM rush hour.


Maybe you could emphasize noise reduction via windows?


The trees sound pretty, though.

 

[jaykim]

Thank you Cedrus and Nik333 very much for the comments.

So, it is not easy to reduce the noise coming from the road. The garden is 20 feet long or so, and I am thinking of spending several thousands if that is going to be helpful. I do not think there is water restriction, except that the water is expensive. So, I think 3 lines of trees might be a good idea to muffle the road noise. I hope it will reduce the noise somewhat.

I will also consider dual windows too.


Thank you very much.

 

[Nik333]

This is interesting about how sound travels.
https://99percentinvisible.org/article/building-wall-highway-sound-barriers-evolution-noise/

 

[SeniorSitizen]

Our house is about 400 meters from a 2 lane 65 mph state highway with heavy native timber between. I'm sorry to say it does very little to possibly nothing to reduce the noise. Be thankful you don't have a 18 wheel truck terminal with drivers proud of their Jake Brakes. Consider researching acoustical wall barrier.


https://www.google.com/search?sourc...pAhXDU80KHaM7C9UQsAR6BAgEEAE&biw=1143&bih=678

 

[Biscuits]

Trees don't help much with noise.

If you have the money, put a dirt berm in that parallels the road. And plant it with grass that's allowed to grow tall.

 

[Cedrus]

I like Biscuits idea, except....plant 50 foot tall bamboo (which technically might be grass).

 

[DoomsDave]

@jaykim, tell us what you do, and how well it works. I have friends who'd like to know more.

 

[DexterII]

I don't know, those walls along freeways must do something given the cost and the number of them that are built, but I have always been amazed at how deep you can walk back into the woods and still hear cars on the road, so am inclined to think that trees aren't going to do much for you. There were a few times when I was hunting or whatever and thought that I was turned around because I had to be closer to the road than intended, then realized that nope, I was fine, the sound was just carrying well that day.

 

[Startingover]

I had a 6’ wood privacy fence installed along a semi busy road as soon as I moved in. So no comparison for me but neighbors on my other side said my fence cut traffic noise drastically.

My other suggestion would be windows. One of my jobs in Planning and Zoning was to call people building new houses, if they were within a certain radius of an airport, and suggesting noise reduction windows.

You can also google ‘trees to reduce noise pollution’ in your planting zone. Some types are better than others, such as ones with branches down to the ground.

 

[3onthetree]

You are in a condo you have to deal with the association. Also, if you can only do 20' length along the back, that won't accomplish much being exposed to each side. Maybe along the entire condo property might help.

Outside, I wouldn't spend thousands on plantings for acoustics. Maybe a noisy water fountain, and if the condo lets you, a wooden fence designed to have variations in its surface (e.g. shadow boxed, slatted, etc).

 

[jaykim]

Thank you 3onthetree, Startingover, DexterII, DoomsDave, Cedrus, Biscuits, SeniorSitizen, and Nik333 for the very helpful comments.

Actually, the house was the one I was bidding to buy, which I really liked except for the noise from the cars. I put in the amount more than the asking price and was confident to get the house, preparing to deal with the noise. That is why I asked this question. But, surprisingly, it turned out that there were 14 bidders, and the highest one was way over the asking price, I heard. So, my attempt to buy fell thru. This is how the housing market is in So Cal.

From this question, I learned a lot, esp Nik333's link for the helpful article. I realized against my thinking that trees do not help a lot to cut off the noise. Biscuits, thank you. I learned a new word, dirt berm. 3onthetree, you have a great memory, knowing that I live in a condo.

Thank you all very much.