Winter desiccation (winter burn)

What it is

Water loss from evergreen foliage in winter when roots cannot replace it

Trees affected

Pines, spruce, junipers, arborvitae and broadleaf evergreens

Where in our area

Wind-exposed yards at any elevation, about 4,000 to 7,100 feet

Key sign

Brown or reddish needle tips, newest growth first, pines half green and half brown

Timing

Appears in late winter and early spring

Northern Nevada winters are dry, windy and often snow-poor, which is the recipe for winter burn. Colorado State Extension says it occurs in warm, windy, low-humidity weather with little snow cover and long dry spells. This page covers what to look for, which trees, what an arborist checks and when pruning or removal is the answer.

What does winter desiccation look like?

Needles turn yellow-brown or reddish, and in pines they look half green and half brown, according to Colorado State. The damage begins on the outer and newest growth and moves along the needle from the tip toward the base. Broadleaf evergreens show leaf scorch. It shows up in late winter or early spring, after the weather that caused it.

The pattern follows wind and sun. The windward side of a tree, a tree on the southwest side of a building and trees along roads and sidewalks are hit hardest. Last year's transplants and trees with limited root space are especially vulnerable.

• Brown or reddish needles from the tips back
• Pines half green and half brown
• Worst on exposed or southwest sides
• Bases of needles and buds can stay green

Which trees and which elevations?

Colorado State lists Manhattan euonymus, pyracantha, holly, Dwarf Alberta spruce, certain junipers, arborvitae and pines among the affected. Our pages for Colorado blue spruce, Austrian pine and junipers cover the evergreens most often planted here.

It can happen anywhere, but the wind-exposed benches and ridgelines are worst, along with Washoe Zephyr winds on the valley floors; see Washoe Zephyr wind and trees. Roots in frozen soil cannot replace water, which is why snow-poor winters matter.

Why does it happen, and how do you tell it from beetles?

Evergreens keep their foliage and keep transpiring through winter. When the soil is frozen or dry, small roots cannot supply water and the needles dry out. Colorado State also notes deicing salt near roads can cause the same symptoms.

A beetle-killed pine usually fades from the whole crown, shows pitch tubes or boring dust and does not green up in spring; see bark beetles in pines. A tree with winter burn often keeps live buds. Colorado State says live buds are soft and pliable. Drought and wind in summer can also make leaves scorch; see drought stress and dieback.

What does an arborist check?

The arborist checks buds and inner needles for life, the pattern of browning against the wind and sun, the roots and soil, whether the tree is new, and whether bark beetle signs are present.

• Live buds on browned branches
• Pattern of damage against wind and sun
• Beetle holes, pitch or boring dust
• Root space and soil
• Age of planting

When is pruning or removal the answer?

Wait. Colorado State says the damage cannot be reversed but that new spring growth is usually not affected, and checks of the buds tell you what is alive. Brown needles do not mean the branch is dead, so pruning in the first spring after damage often cuts live wood. Come back after the new growth has pushed, and then dead tips can be taken out.

Removal is the answer when the tree is dead, when buds are dry and brittle after the new growth should have appeared, or when beetles are in it. A dead evergreen near a house is brittle and a fire hazard; see ladder fuels.

What does Battle Born Tree Service do about winter burn?

Call 775.232.8243 or use the estimate form on this page. An ISA Certified Arborist looks at the tree on site, explains what is wrong and tells you whether the job is waiting, pruning dead tips or removal. Credential WE-11728A is held by one of our two certified arborists. We identify the problem, prune out dead or hazardous wood and remove trees that cannot be saved; we do not spray, inject, fertilize or apply products.