Browning of Eastern White Pines
(Pinus strobus)


Thinning, yellowing and browning white pines.

White pines just off Route 4 in Killington, Vermont.
The white pine in the foreground is browing and yellowing while the needles on the white pines in the background are thinning and yellowing. While this browning, yellowing and thinning of needles was first most visible along highways it can now be seen far from any roads. Many trees have died.
photo by Gerry Hawkes ~ May 2000


The following email thread provides a small insight on the rapid browning of white pines.


-----Original Message-----
From: Jim (name has been changed and email address deleted for privacy)
To: <>
Date: Monday, June 12, 2000 11:14 AM
Subject: Browning of White Pines

Dear Gerry,

Found a posting of yours to a forestry list on the subject of browning of white
pine trees in Vermont from around a year ago.

I've just returned from a weekend trip down from MIddlebury down to Brattleboro
and back and have noticed extensive browning.  In the MIddlebury area it seems
to be occasional with no clear pattern.

A small stand of white pines on my property is dying off rapidly this
spring/summer -- there was no sign of anything similar last year or over the
winter.  The local forestry folks suspect white pine blister rust, but the
signs don't seem to be there for me -- no noticeable problems with the bark,
for example.  It's a horrible feeling just to watch them going and not be able
to do anything about it.

I'm curious to know if you ever found an answer to what was causing the
browning in the Woodstock area.  Thanks for any information you can provide.

Jim (name has been changed for privacy)


-----Original Message-----
From: Gerry Hawkes <>
To: Jim (name has been changed and email address deleted for privacy)
Date: Monday, June 12, 2000 10:37 PM
Subject: Re: Browning of White Pines


There has been a lot of speculation on what is causing the white pines to
brown along highways with most opinions leaning toward roadside salt damage.

I did my senior thesis in forestry school on roadside salt damage and feel
that what we are seeing is only in small part related to salt damage.  More
likely we are observing the effects of automobile and truck exhaust entering
the stomata of the needles and damaging the internal tissues causing the
needles to brown. Studies in Japan in the early 1990' clearly demonstrated
this as the major cause of roadside pines browning there.  Trees that are
weakened by years of acid precipitation, elevated tropospheric ozone levels,
excess UVB radiation and chronic exhaust exposure become more and more
susceptible to browning.

Also I am seeing a significant percentage of pines (white, red & Scots) far
from highways exhibiting thin, chlorotic and stunted needles, but only
occasional browning.  This has become so severe in the last couple years
that I expect we will begin to see a big jump in mortality.

These symptoms in pines,  which have developed virtually simultaneously with
what I consider to be alarming symptoms in most other trees species, can
only be logically explained in aggregate by the cumulative effects of
multiple air pollutants.  Of course there are all sorts of insects, disease
and injuries that plague trees, but only the effects of air pollution can
explain the consistently worsening tree health through both wet and dry
years.  Individual trees will vary in their resistance to air pollution

Identifying white pine blister rust damage is very easy.  You will see white
pitch running from the tree at the point where the blister rust is affecting
the trunk.  Since blister rust attacks very slowly, the trunk often
constricts with time at the point of attack and the needles above that point
yellow and thin over a period of years until the tree dies above the point
of attack.  Frequently the whole tree will die.  Virtually none of the many
browning white pines I have seen had white pine blister rust.

I can not overemphasize how serious the browning of the white pines is as
one more very visible sign that the effects of chronic atmospheric and local
(roadside) air pollution are having an ever increasing adverse impact on our
trees and environment.

I hope this is of some help.  If you have not already done so, you may wish
to go to /air_and_forests.htm and check the links at the
bottom of the page for a small sampling of some of the alarming symptoms
being observed in other species.

Best regards,

Gerry Hawkes
Eco Systems Inc, & Bike Track, Inc.
Woodstock, Vermont


-----Original Message-----
From: Joe Aliff <>
To: Gerry Hawkes <>
Date: Monday, June 19, 2000 10:01 PM
Subject: "The Browning of The White Pines"

Dear Gerry,

I would like to add a paragraph to the story of the browning of the White follows: 

I first became aware of this phenomena in the early 80's when I was traveling widely in relation to studies of like occurrences in many other species of trees such as Hickory,Red Oak, Yellow Poplar, locust, etc. The total browning of a White Pine was quite rare, while needle loss, especially in the older trees, was quite prominent.  To see a White Pine that was one half to two thirds denuded of needles was common, and this was happening in remote sections as well as along highways. The remaining needles of such trees were still green although quite a few of the trees had already died. Snapoffs of the limbs or main trunk of such trees was common and the wood was very brittle--exactly as was happening to the other species--some of which are mentioned above.  However, a fully clothed and totally brown White Pine was quite rare.

We will now step foreword 20 years and take a look at the same scene: While many of  the older White pines continue to suffer needle loss and die a slow death, I am quite safe in saying that their number have greatly increased--an occurrence that is happening in both high and low elevations--in remote areas and along highways. The major difference to occur in this 20 year period, in relation to the White Pine, is in the number of trees that are turning completely brown, and dying with their needles intact.  This event that was once rare is now very common and still seems to be affecting the younger trees-- mostly those of 5 to 20 years of age--with some variance. On my own property, I watched this process unfold, and from the time of onset to complete browning, it took a total of three years.  

I must admit that I see no difference in that which is occurring to the White Pine, and that which is occurring with the many other species of trees, with the exception being that the White Pine is certainly more noticeable.   I hope these notes may be of some benefit to you, and to our many fellow workers.  

Thank you

Joe Aliff
759 Rock Creek RD.
Rock Creek WV    25174




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