Branches dying back from the tips: what the sources say it may indicate

This page reports what the named sources say. It does not say why any branch has died, whether a tree is healthy or what should be done with it. The sources list many possible causes for the same look, and Iowa State says correctly diagnosing the problem is the first step in managing it.

What Iowa State Extension describes

The Iowa State Extension Yard and Garden page Causes of Branch Dieback on Trees says dieback can show on a newly planted tree or one that has stood for decades, and can come on slowly over many years or quickly. It lists these causes.

Cause the page lists	What the page says
Root damage	Digging, trenching, compaction or changes of grade in the root zone, such as for a driveway, patio, foundation or utility, can limit water and nutrients.
Planting depth	A trunk flare below the soil line can bring dieback several years after planting.
Stem girdling roots	Roots that circle or press on the trunk can bring dieback 15 to 25 years after planting.
Drought and wet soil	Too little water, or saturated soil with too little oxygen, damages roots. Young trees and trees with limited rooting space are named as sensitive to drought.
Trunk damage	Mowers, string trimmers, rabbit feeding and deer antler rubbing can disrupt water and nutrient flow.
Diseases and insects	Cankers, vascular diseases and borers can cause dieback. The page says that in many cases environmental stress is the main cause, even when insects or disease are present, because those problems take hold of weakened trees.
Winter and storm damage	Low temperatures and winter drying can kill branches. Storms can partly break limbs high in the crown without the damage being plain.

The page also lists soil pH, salt and herbicide damage. For several causes it says that once the damage is done nothing corrects it, and that prevention is the only route.

What UConn Extension describes

The UConn Home and Garden Education Center fact sheet Dieback of Trees and Shrubs says a number of pests, pathogens and problems can cause dieback. It describes fungi that cause disease only when a plant is already weakened or stressed, entering through wounds from mowers, pruning, breakage or animals. Symptoms it lists include wilting, yellowing and browning leaves, dark and sunken areas on stems, loose bark and browning wood inside dying branches. It tells readers to think about stresses present when the dieback is noticed and also earlier ones, because infection can take weeks or months to show.

What University of Minnesota Extension describes

The University of Minnesota Extension diagnostic page Crab Apple branch dieback is written for crabapple. It sorts dieback by what is seen: winter injury, after very cold winters with little snow cover, where branches leaf out and then die or never leaf out; fire blight, with shoots bent into a shepherd's crook; canker diseases with sunken or cracked bark; drought stress; borers; scale; and black root rot with a thin canopy and small leaves.

Where the sources agree

All three say dieback has no single cause and that the look of one dead branch does not name it. Iowa State names its Plant and Insect Diagnostic Clinic, UConn describes samples sent to its Plant Diagnostic Lab, and Minnesota Extension offers an Ask a gardening question form. The guides on cankers, damage from non-living causes and whether a tree is dying report more.

Who to call

ISA Find an Arborist: the ISA directory for an arborist who can examine a tree
Consulting arborists by country: the credentials and registers consulting arborists hold in each country
Iowa State University Extension: the extension service that published one of the pages; other states have their own extension offices and plant diagnostic labs