A bleeding tree is one that has a condition known as gummosis. This condition is a symptom of several possible diseases, and is commonly seen in both pines and fruit trees. An early warning sign that something else is wrong, gummosis doesn't necessarily mean that the tree will die, but it does mean that you should take a closer look to see what's causing the bleeding.
A bleeding tree is identified by sap that is oozing from the trunk of the tree. Depending on the variety of tree, sap, resin or pitch can play the role of the tree's blood. These gummy substances can seep from large wounds in the bark or something as small as a hairline crack. The sap that leaks from the tree bark itself is generally not life-threatening, even when occurring in relatively noticeable quantities. The color of the gum depends on the type of tree. Bleeding can seem to start and stop when gum is washed away by the rain, but it will return as the tree continues to bleed.
Causes for bleeding trees are wide and varied. A fungal infection called Phytophthora root rot can be the cause of bleeding in conifers; this condition often manifests as bleeding along the base of the trunk and out of sight in the roots. Fungal infections are a major cause of bleeding trees in citrus orchards as well. In cool, damp climates, the fungus can grow so quickly that it will infect the bark and begin to crack it. Insects can also be the cause of a bleeding tree. When boring insects tunnel into the tree's trunk, they leave open holes in the bark that can begin to bleed. The development of cankers can begin to pit and damage the bark, resulting in bleeding.
Bleeding tree is a common condition among citrus trees, especially in orchards where trees stand in close proximity and fungal infections can spread quickly and easily. Cherry trees are among the most popular host plants for borers that cause bark wounds that bleed, and are also prone to developing cankers. Conifers can be highly susceptible to fungal infections, especially spruces, larches, pines and Douglas fir.
How well the bleeding tree recovers and how severe the damage is depends on the diagnosis and how quickly treatment is given. If the cause is a fungal infection, the tree can begin to show other signs of distress such as defoliation, as well as wilted or yellowing leaves and needles. A fungal infection that goes unchecked can continue to rot wood and will eventually kill the tree. A bleeding tree can also be susceptible to other bacterial or viral infections that can invade the tree through the bleeding wounds. While the cracked bark and bleeding isn't problem enough to kill a tree, it can both open the door for other problems as well as be an indicator for illness and disease.