Unusual Growth in Pine Tree

September 30, 2015


Photographer: Menashe Davidson
Summary Authors: Menashe Davidson; Jim Foster
Shown above is a pine tree with an unusual growth as observed in the Horashim Forest of Israel. This area of rolling topography was planted with trees, mostly conifers, in the mid-twentieth century. Pinus brutia (family Pinaceae) is the most numerous species found here. It thrives in Mediterranean climates and can withstand the poor soil conditions of the eastern Mediterranean region. It's a medium size tree, 30 to 60 ft (9 to 18 m) in height at maturity, with an open crown of irregular branches. However, on the specimen above instead of an open crown I noticed this big green ball composed of dense clusters of shortened shoots. This odd nest-like mass is actually a growth referred to as witches' broom or bunch disorder. Insect pests, disease and or fungus may trigger an overgrowth in the affected area of the tree, not always in the upper crown, effectively halting normal growth patterns.