Tree recovery from ice-storm injury

Research Issue

Although ice storms occur throughout much of the northeastern, mid-atlantic, and north central US, the recovery of trees that survive initial breakage had not been documented. A regional ice storm in 1998 in northern New York and New England provided an opportunity to document that recovery.

Our Research

To follow the effects of crown injury on surviving red and sugar maple, paper and yellow birch, white ash, and American beech, we tagged and tracked 516 trees (9”-18” DBH) rated as having lost more than half their crown (high-injury) or less than half their crown (low-injury) at six locations within the affected area. We tested tree response to basal injury after the storm by drilling a hole (3/8” diameter x 2’ deep) at breast-height in each tree in October 1998. We collected increment cores in October 2000 to observe changes in stem growth after the storm compared to pre-storm levels. We recorded tree survival, borehole closure, and internal spread of infection for a half decade after the storm. 

After three years, there was no growth reduction in low-injury trees. Growth reduction in high-injury trees ranged from 20% in ash to 70% in paper birch with maples, yellow birch, and beech being intermediate at about 50%. The stronger the sprouting response to restore lost portions of the crown, the lower the level of growth reduction. We observed little or no sprouting on the merchantable bole in our study. 

After five years, all low-injury trees continued to survive. Survival rates for high-injury trees were 100% for white ash and red maple, 99% for sugar maple, 97% for American beech, 90% for yellow birch, and 55% for paper birch. Tree dissections showed that dead birch trees contained advanced rootrot disease that was initiated by infection prior to the 1998 storm. 

Tests of tree response to borehole injury indicated that ash was most effective in responding to the basal wound with about half of the boreholes closed after 1 year and nearly all closed after 3 years, regardless of the amount of crown lost. In paper birch, cambial dieback was associated with all boreholes and no boreholes were closed after three years. In sugar and red maple and yellow birch, borehole closure was greater and cambial dieback was less in low-injury trees compared to high-injury trees. 

Tree dissections showed that even with extensive crown loss, compartmentalization was effective in resisting the spread of infection in living sapwood. After 4 years, columns of discolored and infected wood associated with the broken tops or branches had spread from a few inches to a few feet from the wound surface, and generally did not spread into the merchantable bole. However, compartmentalization was much less effective and discoloration and infection more extensive in trees with advanced root rot and with broken tops that failed to sprout. 

Tree damage was strongly related to: 

1. Tree health before the storm, particularly with respect to root disease, 
2. Ability to sprout and rebuild crowns, and 
3. Closure of open wounds. 

Prediction of recovery requires looking for signs of infection in the roots and butt of trees and assessing the capacity for crown restoration, as well as estimating crown breakage and loss. 

Expected Outcomes

These results inform foresters and land managers that northern hardwood trees and forests can quickly recover from crown injury if they are in good condition at the time of the storm. 

Research Results

Shortle, W.C., K.T. Smith, and K.R. Dudzik. 2003. Tree survival and growth following ice storm injury. USDA For. Serv. Res. Pap. NE-723. 4 p. 

Smith, K.T. and W.C. Shortle. 2003. Radial Growth of Hardwoods following the 1998 ice storm in New Hampshire and Maine. Canadian Journal of Forest Research 33: 325-329. 

Smith, K.T., W.C. Shortle, and K.R. Dudzik. 2001. Patterns of storm injury and tree response.USDA Forest Service, NA-TP-02-01.  

Research Participants

Principal Investigators

• Kevin T. Smith, US Forest Service- Northern Research Station, Plant Physiologist
• Walter C. Shortle, US Forest Service- Northern Research Station, Research Plant Pathologist

For further details log on website :
http://www.nrs.fs.fed.us/disturbance/forest_health/ice_storm_tree_recovery/