I love the red maple tree. I think that they are beautiful – spring & fall. I love the color. The red maple tree is medium-sized with a distinctively shaped three-lobed green leaves with jagged edges, bright red stems and silver white undersides.
In the spring, the tree buds are bright red. In autumn, the leaves of most red maple trees turn fiery scarlet, but a few others produce bright yellow or orange foliage. The bark is smooth and pale gray on younger trees, becoming dark and broken with deep grooves with age.
But as I just recently discovered. The Red maple tree is on the Toxic Plant list for our Beloved Horses.
Toxicity: Wilted or dried red maple leaves are extremely dangerous to horses. They contain concentrated amounts of gallic acid and other identified toxins that cause Heinz body anemia, a breakdown of the red blood cells that prevents them from carrying oxygen. The kidneys, levier and other organs may also be damaged. As little as a pound or two of leaves can be fatal. since all the parts of the maple contain the toxin, there is the potential for the green leaves to also cause poisoning. Why horses are not as readily poisoned by the green leaves may be due to palatability issues and that the the toxin is not as concentrated in the green leaves.
Signs of Poisoning: Lethargy; red, brown or black urine; colic, refusal to eat; pale yellowish gums and mucus membranes that progress to black; increased respiratory rate; rapid heart rate; dehydration. Depending on how many leaves were eaten, it may take a few hours up to several days for signs to appear.
Treatment: There is no specific treatment for red maple poisoning, but supportive care, including large amounts of intravenous fluids, vitamin C and possibly blood transfusions, may help a horse survive. Chances for recovery depend on how many leaves the horse consumed and how quickly veterinary care can be instituted.
Control Measure: Pick up fallen branches and rake and remove fallen maple leaves promptly. The decision to remove red maple trees and possibly silver and sugar maples will depend on individual circumstances, and horse’s desire to seek out and eat maple leaves, and the potential risk one is willing to accept. At least two other species, the silver and sugar maples, have also been shown to contain the same toxins as red maple trees, although in lesser amounts. Red maple trees have also ten used to produce many hybrids and cultiars that are sold for ornamental plantings. the toxicity of each of these varieties is unknown, but it’s safest to assume they may contain some amount of the gallic acid. For those reasons, avoid planting any of these maple trees where the leaves will fall or blow into pastures.
One last note — Please note that the red maple is a different species than the Japanese red Maple and the red – or purple – leaved varieties of the Norway maple.
I wish I could take credit for this information but I have to give credit to Katie Frank “A field Guide to Toxic Plants”, Equus, April 2012.