Physiological problems in evergreen, or coniferous trees include a condition known as evergreen browning and it is caused by excessive water loss. In the late part of winter and early spring many evergreen trees take on a reddish brown appearance, usually more toward their branch tips. Unlike deciduous trees, evergreens keep their needles, or leaves, year-round. About March, when air temperatures increase, Evergreen needles will start to transpire, or lose water. However, as their roots are bound in ice, they cannot take up water to replace what is being lost through the needles. This moisture loss causes the needles to turn brown. Strong winds will also cause water stress to exposed needles, which is why evergreen browning tends to occur on the areas most exposed to the southwest.
To minimize this effect, make sure trees are well watered especially in late fall, before freeze up. Wherever possible, trees should be protected with burlap sunscreen. As most evergreens are shallow-rooted, they require watering almost constantly during periods of hot, dry weather. Trees that do not get enough water during hot, dry weather tend to suffer from needle browning and occasionally branch dieback. To try to minimize this effect in spring make sure trees are kept well – watered and fertilized to encourage new growth.