Question
I have 4 pine trees that have gone through one of the wettest summers on record here in Central Texas. All of the trees have browning needles. The needles that have access to sunlight seem to be ok. The needles that are beneath are the ones that are turning brown. A friend told me it was because of the excessive rain. The rain has since stopped, but the condition is still there. What do you think the problem is?

Answer
If pine needles turn brown from the interior of the tree, and the outer needles stay green, there is no cause for alarm.

Everyone knows that deciduous trees lose their leaves in the fall, but fewer people learn that evergreen trees also lose their old needles sometime in the late summer or fall. Needle age at which drop occurs varies among evergreens and within species.

Loblolly, longleaf, slash, and shortleaf pines go through a natural process of shedding their oldest needles (the inner most needles on branches or needles near the trunk) in the autumn. Usually the old needles turn yellow and then straw colored to brown before dropping. In a similar fashion,

All trees and shrubs have to renew their foliage annually, producing new leaves and then shedding old ones. The leaves of deciduous trees and shrubs live only a few months, whereas those of evergreens live from one to several years, depending on the species. After producing new leaves, evergreens shed the oldest ones.

Occasionally fungus needle blights may be involved in browning of pine needles, but such blights are more unsightly than anything else and usually are not responsible for significant damage to trees.

If the needles are green on the upper and outer parts of the branches then the tree is OK and just shedding the old needles. Sounds like what you have there.