Poplars are well-known deciduous trees. They have been a large part of the American timber industry, which has led to the development of a fast-growing and popular hybrid. Commercial planting of poplars began in the 1970s as part of a government reforestation and reclamation project. Poplars are members of the willow family and have crossed with native tree species to create natural hybrids. Poplar trees are known to be extremely fast growing and have a variety of shapes and uses.
Poplars are closely related to cottonwoods and aspens. They have also cross-pollinated with these trees, creating hybrids of the two species. All poplars are deciduous, but leaves and canopy shape is different among the trees. White Poplar and Balm of Gilead Poplar were introduced from Asia. Cottonwood or Eastern Poplar is a massive hybrid, as is Swamp Poplar. Bigtooth and Quaking Aspen are also poplar hybrids. Southern Poplar is native to the U.S. and Lombardy Poplar is a cultivar.
Poplars are considered short-lived trees. There are trees that can live a 1,000 years and the poplar lifespan is one-tenth of that on average. The key may be the rapid growth of the plant. Producing repetitive cell cloning takes energy that is not expended on other tree processes. Some poplar species live longer than others--the growth rate may provide a clue why.
The Virginia Big Tree Program has compiled a list of common trees of the Americas and their life spans. The Balsam Poplar lives an average of 100 years and can live up to 150 years. The Yellow Poplar has a much longer life span at 250 years on average, and a maximum of 450 years. The Hybrid Poplar will only reach 30 to 50 years of age, a relatively short life span. It is primarily used for timber and harvested between six and 12 years old.
Poplars will only live as long as environment and man will allow. Trees are heavily influenced by pollution and environmental stress. Poplars are often plagued by fungus, cankers and blight. Bronze birch borer and gypsy moths are just two of numerous pests that afflict poplars. Forestry management has some affect on tree age, due to culling to increase green spaces and encourage a healthy deciduous forest. Tree age is also influenced by adequate growing space.
All poplars are known to be prodigious growers. The Lombardy Poplar is often planted as a hedge or windbreak as it will mature in just a few years. Hybrid poplars grow around 6 feet per year and can reach maturity in a short time. They can reach 20 feet high in just three years with a full mature height of 70 feet tall. The growth rate relation to life span shows promise in the case of the hybrid poplar, a rapid grower with a short life span.