That winter a lot of plants here in northeast Ohio were damaged. Exposed tender new growth is susceptible to frost and freeze damage in spring. An old bed sheet or frost cloth can prevent brief subfreezing temperatures from killing the new foliage and stressing the tree. Some Japanese maples were damaged as well, and this is what I observed.

That damage looks like either frost/wind or sun damage or a combination of them. This is why severe frosts cause problems for fruit tree owners.
I'd move the mulch away from the tree trunk - just leave a clear ring not touching the trunk.

As a result of these damaged cell walls, the plant defrosts too quickly, killing leaves and stems. Light frost typically doesn’t cause major damage, with exception to very tender plants, but hard frost freezes water in plant cells, causing dehydration and damage to cell walls. I had bought a foot tall Japanese Acer Sangokaku 2 weeks back and placed the pot in the house during daytime and at night time in the porch in order to protect it from frost… Keep mulch 4 to 6 inches away from the trunk of the tree. This is a common problem on Acer palmatum varieties here in the UK- usually, the cause is wind, that is, you've placed the plant in a spot which isn't sheltered enough.

Careful Covering

Given that the freeze was unprecedented, it was difficult to decide how to do corrective pruning of damaged trees based on previous experience. Northwind Maple Information Jack Frost maple trees are crosses between Japanese maples ( Acer palmatum ) and Korean maples ( Acer pseudosieboldianum ).

The Easter freeze of 2007 caused serious damage to many species of landscape plants.

There were two, well established Acer palmatum dissectum (lace-leaf weeping JM) that I saw with severe damage.

Cold weather, particularly frost, causes the water in plant cells to freeze, damaging the cell wall. This bacteria is considered opportunistic because it usually attacks plants that have already been damaged by frost or by other means. First, your Acer is not dying, it's just very unhappy. They hate windy areas, and they don't like hot midday sun in high summer either. Cold injury is more likely to occur as the sun comes up.

Among the most seriously injured were various cultivars of Japanese maple. In the case of many growing trees, growing might be stunted and all leaves will die.

Things like well established privet and hollies were devastated.

They have the beauty of the Japanese maple parent, but the Korean maple’s cold tolerance.

It will probably recover but avoid leaving any water on the leaves if more frost is due. Newly emerged growth is quite succulent and susceptible to damage from strong winds and below freezing temperatures. The new leaves have died because frost is traumatic for any tree or vegetation.
Japanese maple leaves can be spotted and the veins within the leaves can be blackened.

Planting and caring tips for Acer Japanese Maple ... 3:07. Frost damaged magnolia foliage This spring's unseasonably warm weather in late March and the first three weeks in April encouraged many trees and shrubs to leaf out earlier than normal. This will protect roots from frost damage and help keep roots moist in the well-drained soil preferred by Japanese maples.