General Question

flo's avatar

Why is there such a thing as an evergreen tree with brown/dry areas?

Asked by flo (13313points) August 22nd, 2012
20 responses
“Great Question” (1points)

Isn’t there a reason why they call them evergreen? I haven’t actaully seen any, but some people have witnessed some evergreen trees with brown dry areas lately. What causes that?

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chyna's avatar

Disease or not enough water.

WestRiverrat's avatar

Pine beetles, other insects or molds and diseases all can brown evergreen trees.

There are also some pines like the tamarack pine that are decidious and lose their needles every year.

augustlan's avatar

Diseases and insects.

Adirondackwannabe's avatar

They’re not larch are they?

Jeruba's avatar

When I was in Glacier National Park in Montana recently, the guide on a boat tour of one of the lakes explained that huge swaths of spruces growing on the lower parts of the surrounding mountains were rust brown because they were being killed by pests. I’ve forgotten the name of the pests. She said that the only thing that would stop them was fire and that in the natural course of things those forests would burn. She showed us where some had burned already. Then the pests are gone, the trees regrow, and the cycle continues.

WestRiverrat's avatar

@Jeruba it probably was pine beetles. They have become widespread through out the northern Rocky Mountains recently.

gailcalled's avatar

I have field-grown accidential white pines that drop a huge amount of brown needles every fall. It is nature’s housekeeping.

Jeruba's avatar

@WestRiverrat, the term had three words. The third one was probably “beetles.” I think the first two were each one syllable. They were common words; I just wasn’t familiar with the combination.

WestRiverrat's avatar

@Jeruba there are several varieties of pine beetle that are working their way through the forests, one of them is the bark pine beetle.

The one we are dealing with locally is the western pine beetle.

But we probably shouldn’t hijack @flo‘s question anymore.

gailcalled's avatar

She asked about various causes of evergreen depredation.

Here we have the white pine borer that attacks all the pines.

Trillian's avatar

Conifers are otherwise known as evergreens. link

Jeruba's avatar

Yes, yes, yes, @gailcalled, spruce budworm. That was it. So it’s one of the things that cause evergreens to go brown and dry. The more general answer is: because they’re dead or dying.

woodcutter's avatar

Could be gypsy moths. Many years ago up in New England they all but destroyed the trees there. Stress from drought kills parts of trees.

glacial's avatar

It is also quite normal for certain conifer species to have their lower branches die and fall off as they age. Pines do this, for example. That’s what made white pines such great masts for ships back in the day.

flo's avatar

Thanks to all.

The description I heard from the elderly person who lived in N.America all her life is that it is as if someone went with a brown spray can and sprayed a small patch of the tree on top for example, the rest of the tree is fine. I hope someone will come up with some treatment anyway.

flo (13313points)“Great Answer” (0points)
Adirondackwannabe's avatar

I bet it’s white pine rust. What other trees are nearby?

flo's avatar

@Adirondackwannabe I don’t know I’ll have to find out and report, but I’m sure you’re all right.

flo (13313points)“Great Answer” (1points)
gailcalled's avatar

N. America is a big place. Where precisely are these trees growing.

Here in the NE I have many accidental white pines. They are all attacked by a pine borer. That destroys the single leader (used for those ships’s mast.) All the mature trees have a trunk, then a little platform and three or four large mini-leaders growing from that. The trees look wider and bushier but flourish in spite of the borer.

flo's avatar

@gailcalled I don’t know the person so it will take a while before I find out.

flo (13313points)“Great Answer” (0points)

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