Maple trees are ancient, going back a million years or more. Of 128 species of maples, the bigleaf maple, Acer macrophylum, is the only one native to northwest coastal regions. These multi-trunked giants are the tallest of the maples typically ranging from 12-23 metres tall, some recorded as tall as 48 metres! Bigleaf maples also have the largest leaves of any tree in North America! Some reportedly reaching 60 cm wide, although the average size is about 30 cm. Tree leaves act as solar panels and allow the tree to store energy from the sun. Because bigleaf maples have huge leaves, they can store a lot of energy which will be converted to food through photosynthesis. Maples are very often seen in riparian zones after fires or logging since they have high productivity rates and easily regenerate. They can grow over 3 metres in 1 year. They have evolved with local insects and disease pathogens therefore disease and pest problems tend to be minimal, and survival rate of these trees is typically high. They can live to 300 years or more in the right conditions.
Maples Give Back to Nature.
Maples are important to the ecosystem in which they live. Plants, animals, soil, and even aquatic life benefit from these majestic giants. During growth bigleaf maples require high amounts of nutrients along with water, which they absorb from the soil. Trees have small tubes, called xylem, that extend from its roots and run throughout the tree transporting water and nutrients; this is the sap. The entire tree becomes rich in nutrients, and the bark especially high in calcium. This is ideal for air plants like mosses, liverworts, and licorice ferns. Air plants don’t require soil to grow and thrive on the bigleaf maples nutrient rich bark as substrate.
Moss load on bigleaf maple trees is typically the greatest of all the tree species in the Pacific northwest. In coastal rain forests a bigleaf maple could be supporting up to 1 ton of mosses. These trees are experts at aerial gardening.
In fall, bigleaf maples produce a lot of leaf litter. Their leaves are enormous. High nutrient content in leaves promotes quick decomposition, typically within a year. As leaves break down, nutrients are released back into the soil, improving soil quality. In addition, a deep widespread root system holds soil in place, and prevents it from becoming compact. This allows water to soak into the ground instead of flowing over the surface and washing away loose soil. Widespread leaves and branches act as a wind break and rain control so soil is not blown away or washed out. Thus, bigleaf maples help minimize erosion.
Long leafy branches provide a source of shade and shelter in the summer. As a bigleaf maple grows it drops its lower branches, creating nooks and crannies in the tree that small animals and birds love to nest in. Branches that fall on the ground provide woody debris for other plants to germinate on and give shelter to small creatures. When the branches fall into the creek they enhance the habitat quality for aquatic life. Maplewood decays more rapidly than other wood because of its high nutrient content, providing organic matter that is readily available as food in the water. Branches hanging over the creek also provide a tasty snack for fish when bugs fall into the water.
Early in spring, maples are a very important nectar source for bees and insects coming out of hibernation. They have an abundance of flowers which provides a much-needed food source after a long sleep. When their seeds spin to the ground in late spring, they provide food for various critters.
Maples in Danger
Big leaf maples are being impacted by climate change, and instances of die-off have been increasing over the past decade. Rising temperatures and drought conditions are making survival more challenging for bigleaf maples. During extremely dry conditions, bubbles can form in a xylem tube, possibly rendering it unusable forever. If a tree cannot get enough water or nutrients, it will inevitably die.
In some areas, bigleaf maples are reportedly producing smaller leaves with a yellowish scorched appearance, and leaves are falling much sooner than they should. This is especially evident near roads and developed urban areas where temperatures are higher. Without healthy leaves, photosynthesis can’t happen, and a vicious cycle begins. The tree gets stressed and must put energy into simply surviving instead of growing large leaves; however, without these large leaves, the tree is unable to produce enough food, which causes it more stress. A stressed and weakened state makes the tree more vulnerable to pests, disease, and extreme weather, such as wind and ice storms.
Climate extremes are an issue when the weather warms up for a few weeks and triggers the tree to produce new buds, then suddenly drops. New buds could freeze, dry out, and die. This results in the loss of a whole phase of new growth, which took up much of the tree’s energy reserve to produce. If the tree is already in a weakened state, replacing these buds could be a struggle and could result in starvation the following year.
