Lab #1 Non-infectious Diseases
Damage Caused By Temperature Extremes
Winter Sunscald: The bark has detached on these young maple trees at areas where the cambium was been killed due to inter sunscald.
Frost Cracks: Successive years of frost cracks cause large folds of callus to develop. Frost cracks develop in areas where previous wounds were located.
Winter injury from low temperatures can affect trees that are not well suited to Minnesota's climate. This is yew with the early stages of winter injury and branches are chlorotic. These affected branches will turn red in time and die. Branches below the snow are usually not affected.
Yew branches turn red over time after winter injury. These dead branches were not covered by snow and were exposed to very low temperatures.