The freezing temperatures that occur in Ohio and Michigan during with winter months can place stress on our trees and shrubs, especially if we experience multiple freeze and thaw periods. Needles can brown out, bark can split (and the inner tissue of the tree can experience dieback) and root damage. Most damage will occur on the South or Southwest side of the tree where it receives most of it's sunlight.

Sunscald
What will typically happen is the warmth of the sun tells the tree that it's alright to continue growing under the bark (the inner tissue). Cells become active though as the sun sets and the temperatures drop the recently activated cells under the bark of the tree become damaged by the freezing temperatures (the tree was unable to cease activity prior to the temperature drop). This can cause sunscald and will show up as streaking or sunken areas down the trunk or branch of the tree.

Desiccation stress
When winter days are above freezing (though the soil has had adequate time to freeze), needles on conifers will naturally transpire water (evaporation through the needles). Since the ground is frozen the root structure is unable to pull water back to the branch and replace the lose of moisture the needle experienced. This will cause browning and die back of needles. If needles begin to brown that does not mean the whole branch is dead. Wait until bud break of the following spring to monitor the tree and see if there is still life in the branches affected. If late summer or fall do not offer adequate moisture, ensure that you give your trees about 6 inches of water before early-September. After the early September watering, wait until your deciduous trees have dropped all their leaves and water one more time before the ground freezes.

Damage to look for : Browning or bleaching of needles Cracks in tree's bark