Drought stress and dieback

Early signs

Brown or curled leaves, scorched leaf edges, early leaf drop; browning needles in conifers

Later signs

Dead twigs and branch tips in the upper crown, then sucker growth along the trunk

Timing

Symptoms may not show for one to two years after the event

Follow-on problems

Wood borers, root rots, cankers; bark beetles in pines

Local setting

Valley and foothill stations average about 4 to 12 inches of precipitation a year

Stressed trees are open to borers, root rots and bark beetles. Northern Nevada trees live on little natural water, and most of the trees in our yards are watered by people. When the water falls short, the tree reports it slowly. This page covers the signs, the pattern dieback takes, and when pruning or removal is the right decision. Battle Born Tree Service does not spray, inject or apply products to trees. We identify the problem, prune out dead or hazardous wood and remove trees that cannot be saved.

What does drought stress look like?

Michigan State University Extension lists the first signs in broadleaf trees as brown or curled leaves, scorched leaf edges and sometimes early leaf drop. Montana State University Extension adds premature fall color. In conifers the signs are browning needles and wilting twigs. Utah State University Extension notes that several years of scorch can show up as dieback in the upper canopy, and that sucker growth along the trunk is a later sign of stress.

Timing is the trap. Texas A&M Forest Service notes that scattered trees are likely to die for several years following a drought. A tree that dries out in August can look fine until the next summer.

How does dieback differ from other problems?

Drought dieback starts at the top and the outer edges of the crown, where water has the farthest to travel, and moves inward. Leaf browning between the veins on every branch is more likely scorch. Browning on one limb only points to a different cause, such as a canker, a girdling root or a broken limb. Lace-like leaves are insects; see elm leaf beetle. A pine or fir whose whole crown fades after a dry year may have been attacked by beetles; see bark beetles in pines and fir engraver.

Why is it a local problem?

NOAA's 1991 to 2020 normals put annual precipitation at 4.15 inches in Hawthorne, 4.77 in Fallon, 7.35 at the Reno airport and 9.34 in Carson City, and 11.7 inches at Virginia City. See climate normals by station. A tree on the valley floor survives on irrigation, so a broken sprinkler zone, a changed watering schedule or a lawn removal can be enough to start a decline.

What does an arborist check?

An arborist checks the pattern of the dead tips, the root crown and soil, signs of borers, cankers or bark beetles, and how much of the crown is dead. They also look for dead limbs that could fall.

• Whether the dead tips follow a pattern that suggests water supply, such as the side of the tree away from the irrigation
• Root crown and soil: compaction, recent digging, grade changes or covered roots
• Signs of borers, cankers or bark beetles on stressed wood
• The percentage of the crown that is dead, and whether live buds and green cambium remain
• Dead limbs that could fall onto a roof, driveway or play area

When is pruning or removal the answer?

Texas A&M Forest Service notes that wood borers, root rots and canker diseases are especially common after drought, and bark beetles are a concern for pines in the year or so after a dry spell. That is why dead wood in a stressed tree is worth removing: it is the first place these problems take hold, and it is the part most likely to fall. See dead wooding. Watering is up to the tree's owner; our guide covers it for the high desert: watering mature trees.

Removal is the answer when the crown is mostly dead, when scratching the twigs shows no green tissue, when decay has reached the trunk or roots, or when the tree is too close to a house to leave dead wood overhead. A tree that has a lot of live crown left and a sound trunk is usually kept, with the dead wood pruned out. Call 775.232.8243 for a free estimate and an assessment by an ISA Certified Arborist. See tree removal and how to tell if a tree is dead or dying.