• Piene, Harald
  Research Scientists Maritimes Forest Research Centre Fredericton, N.B.
  
• MacLean, David A.
  Research Scientists Maritimes Forest Research Centre Fredericton, N.B.
  
• Goldman, Suzanne E.
  International Paper Company Bangor, Maine
  
• Searcy, Janet
  Information Coordinator CANUSA Program USDA Forest Service Washington, DC
  
• Oliveri, Stephen
  Environmental Research Coordinator Maine Forest Service, Department of Conservation Augusta, Maine
  
• Grimble, David G.
  Applications Coordinator CANUSA-East Broomall, Pa.
  

Forest managers must be able to predict accurately wood production of different stand types in order to allocate harvesting for a sustained yield. When it is forecast that the forest resource will be in short supply, as it will be for some provinces in eastern Canada, the precision of wood supply predictions becomes very important. The manager must have reliable information about growth rates of forests and the effects on growth of external influences such as budworm defoliation. However, few data presently exist to quantify the loss of wood production. Past studies of the effects of defoliation on the growth of host trees have generally lacked detail and often considered only growth loss at breast height.