The effect of Viscum album L. on annual diameter increment of Pinus nigra Arn.

In this study, the influence of infestation by mistletoe (Viscum album L. subsp. austriacum (Wiesb.) on the annual diameter increment of Anatolian black pine (Pinus nigra Arn. subsp. pallasiana (Lamb.) Holmboe) in Goksun district (Kahramanmaras province, Turkey), was investigated. Differences among annual diameter increment measured in nine growing years between 1992 and 2000 were significantly (P < 0.001) affected by the infestation of the mistletoe. The percent decrease in the annual diameter increment of infested trees ranged between 36 and 50% depending upon the years. In conclusion, the annual diameter increments of Anatolian black pine trees were reduced by about 41% within 9 years due to infestation by the mistletoe.