Why are the needles on my white pine turning brown? Is there something I can...
Why are the needles on my white pine turning brown? Is there something I can do to correct this problem?
Wayne County Michigan trees and shrubs
Several things can cause browning needles on white pine. The most common thing is the natural browning, and dropping, of the older, inner needles. Needles that are 4-6 years old will yellow, then brown and drop in the fall.
It is normal for conifers to drop their oldest needles in the fall. This annual shedding occurs on all trees at about the same time, and always occurs in the fall. If this is the case for your tree, there is nothing for you to do. Just give the tree 'good care' by mulching and watering, as noted below under 'drought stress.'
An abnormal needle drop would occur in the spring or summer, affecting only one or a few trees, rather than all or most of them.
Another common issue is drought stress. Last year’s drought, and this year’s lower than normal rainfall in September, can cause the tree to brown and drop more needles than usual. Provide a 2-3 inch deep mulch from trunk to the edge of the tree’s branches (without the mulch touching the trunk of the tree); and slow, deep watering of the root zone all the way around the tree ( a soaker hose is a good way) during times of drought- be careful not to flood the root zone, especially if you have clay soil.
Poor conditions in the root zone can cause pines to lose needles early- and possibly kill the tree. Watch for compacted soil, standing water or flooding, cutting major roots, parking vehicles on the roots, etc.
Injury from de-icing salt also causes the death of white pine needles and branches. Symptoms from salt show up on the side of the tree closest to the salted road. Trees closest to the road are most severely injured.
There are needle blights that can affect white pine- here is a link to an article about blight. It was written for Christmas tree farmers, but the disease symptoms can be compared to your situation http://msue.anr.msu.edu/news/managing_dothistroma_and_brown_needle_blight_on_pines
If you think a disease is involved, you can confirm this a couple of ways. You can send a sample to MSU’s diagnostic lab for a fee- see www.pestid.msu.edu for fees, how to send samples, etc. It is a good idea to call the lab for instructions, if you aren't sure how to take a sample for them.
Or you can consult a certified arborist, who will come on site, evaluate the tree as a whole, and give a diagnosis and a plant heath care guide. See www.treesaregood.com and click on the ‘Find a Tree Care Service’ tab at the top of the page. Contact 2-3 arborists and get estimates.
As you can see there are many factors that can be in play. If you have more questions, please update this question again. Thank you for using our service.