User:Solistide/sandbox/Acer rubrum

Ecology
Red maple seldom lives longer than 150 years, making it short to medium lived. It reaches maturity in 70 to 80 years. Its ability to thrive in a large number of habitats is largely due to its ability to produce roots to suit its site from a young age. In wet locations, red maple seedlings produce short taproots with long and developed lateral roots, while on dry sites, they develop long taproots with significantly shorter laterals. The roots are primarily horizontal, however, forming in the upper 25 cm of the ground. Mature trees have woody roots up to 25 m long. They are very tolerant of flooding, with one study showing that 60 days of flooding caused no leaf damage. At the same time, they are tolerant of drought due to their ability to stop growing under dry conditions by then producing a second growth flush when conditions later improve, even if growth has stopped for 2 weeks. Red maple is one of the most drought-tolerant species of maple in the Carolinas.

A. rubrum is one of the first plants to flower in spring. A crop of seeds is generally produced every year with a bumper crop often occurring every second year. A single tree between 5 and 20 cm in diameter can produce between 12,000 and 91,000 seeds in a season. A tree 30 cm in diameter was shown to produce nearly a million seeds. Red maple produces one of the smallest seeds of any of the maples. Fertilization has also been shown to significantly increase the seed yield for up to two years after application. The seeds are epigeal and tend to germinate in early Summer soon after they are released, assuming a small amount of light, moisture, and sufficient temperatures are present. If the seeds are densely shaded, then germination commonly does not occur until the next Spring. Most seedlings do not survive in closed forest canopy situations. However, one- to four-year-old seedlings are common under dense canopy and though they eventually die if no light reaches them, they serve as a reservoir, waiting to fill any open area of the canopy above. Trees growing in a zone 9 or 10 area such as Florida will usually die from cold damage if transferred up north, Canada, Maine, Vermont, New Hampshire and New York, even if the southern trees were planted with northern red maples. Due to their wide range, genetically the trees have adapted to the climatic differences.

Red maple is able to increase its numbers significantly when associate trees are damaged by disease, cutting, or fire. One study found that 6 years after clearcutting a 3.4 ha Oak-Hickory forest containing no red maples, the plot contained more than 2,200 red maple seedlings per hectare (900 per acre) taller than 1.4 m. One of its associates, the black cherry (Prunus serotina), contains benzoic acid, which has been shown to be a potential allelopathic inhibitor of red maple growth. Red maple is one of the first species to start stem elongation. In one study, stem elongation was one-half completed in 1 week, after which growth slowed and was 90% completed within only 54 days. In good light and moisture conditions, the seedlings can grow 30 cm in their first year and up to 60 cm each year for the next few years making it a fast grower.

The red maple is a used as a food source by several forms of wildlife. Elk and white-tailed deer in particular use the current season's growth of red maple as an important source of winter food. Several Lepidoptera (butterflies and moths) utilize the leaves as food; see List of Lepidoptera that feed on maples.

Due to A. rubrum's very wide range, there is significant variation in hardiness, size, form, time of flushing, onset of dormancy, and other traits. Generally speaking, individuals from the north flush the earliest, have the most reddish Fall color, set their buds the earliest and take the least winter injury. Seedlings are tallest in the north-central and east-central part of the range. The fruits also vary geographically with northern individuals in areas with brief frost free periods producing fruits that are shorter and heavier than their southern counterparts. As a result of the variation there is much genetic potential for breeding programs with a goal of producing red maples for cultivation. This is especially useful for making urban cultivars that require resistance from verticillium wilt, air pollution, and drought.

Red maple frequently hybridizes with Silver Maple; the hybrid, known as Freeman's Maple Acer x freemanii, is intermediate between the parents.

Allergenic potential
The allergenic potential of red maples varies widely based on the cultivar.

The following cultivars are completely male and are highly allergenic, with an OPALS allergy scale rating of 8 or higher:


 * 'Autumn Flame' ('Flame')
 * 'Autumn Spire'
 * 'Columnare' ('Pyramidale')
 * 'Firedance' ('Landsburg')
 * 'Karpick'
 * 'Northwood'
 * 'October Brilliance'
 * 'Sun Valley'
 * 'Tiliford'

The following cultivars have an OPALS allergy scale rating of 3 or lower; they are completely female trees, and have low potential for causing allergies:


 * 'Autumn Glory'
 * 'Bowhall'
 * 'Davey Red'
 * 'Doric'
 * 'Embers'
 * 'Festival'
 * 'October Glory'
 * 'Red Skin'
 * 'Red Sunset' ('Franksred')

Toxicity
The leaves of red maple, especially when dead or wilted, are extremely toxic to horses. The toxin is unknown, but believed to be an oxidant because it damages red blood cells, causing acute oxidative hemolysis that inhibits the transport of oxygen. This not only decreases oxygen delivery to all tissues, but also leads to the production of methemoglobin, which can further damage the kidneys. The ingestion of 700 grams (1.5 pounds) of leaves is considered toxic and 1.4 kilograms (3 pounds) is lethal. Symptoms occur within one or two days after ingestion and can include depression, lethargy, increased rate and depth of breathing, increased heart rate, jaundice, dark brown urine, colic, laminitis, coma, and death. Treatment is limited and can include the use of methylene blue or mineral oil and activated carbon in order to stop further absorption of the toxin into the stomach, as well as blood transfusions, fluid support, diuretics, and anti-oxidants such as Vitamin C. About 50% to 75% of affected horses die or are euthanized as a result.