Forest
Stewardship News Release
April
20 , 2009- For Immediate Release
Contact: Allyson
Muth, Phone: 814-865-3208, E-mail:
Tree Flowers: Spring Color in the Landscape
At this time of year, vegetation is bursting in to bloom. We notice the bright colors of showy flowers, watch busy pollinators, and pay attention to the changing landscape as everything softens from winter's hard edges. We tend to notice the "big" and the "bright," but what about the less showy flowers?
Trees have such a dominant place in our landscape -- their trunks present a solid maze as we peer across a forest stand; their height inspires; their girth impresses. What about their flowers? Have you ever taken the time to notice the subtleties of the largest vegetation?
Tree flowers come in different shapes and sizes from the large, showy, and perfect (more on this in a minute) flowers to the miniscule and drab. Most often an appreciation of tree flowers requires a hand lens or magnifying glass.
Right now, in central Pennsylvania, we're seeing the red maples and the aspen in bloom. Soon redbud and dogwood will make themselves known. Oaks and hickories flower when their leaves are beginning to unfurl. Others wait until their leaves are fully formed before flowering.
Some species have "perfect" flowers with both male (stamen) and female (pistil) parts. The stamens shed pollen and the pistils receive it to fertilize an egg which develops into seed. These self-pollinators don't require much outside "help" to get to seed.
Other tree species have both male and female flowers on the same tree. Pollen must be carried from one to the other to fertilize the eggs. Trees that have both genders of flower on the same tree are monoecious -- a Latin word meaning same house. Other species such as willows, aspen, and sassafras are dioecious -- another Latin word meaning two houses -- with only male flowers or female flowers on a given tree. When pollen must travel far, or to ensure cross-fertilization (instead of self-fertilization), it needs either an efficient delivery mechanism or ample quantities to ensure the production of seed offspring.
Most trees are wind pollinated and have flowers that don’t last very long. These wind pollinated species produce pollen in great abundance, have smaller flowers, and tend to flower in early spring before leaves appear, thus ensuring maximum airflow among the trees and flowering branches. Most of these abundant pollen producers, such as oak, hickory, and alder, can cause allergenic reactions to humans.
Most of the conifers found in the Pennsylvania are monecious. If you look carefully, the male flowers are often lower in the crown and the females up higher where the cones form. This flower arrangement helps reduce self-pollination. Thus when the wind blows, it has to lift the pollen to the female flowers, which are most often in another tree as the wind seldom lifts the pollen straight up. It also puts the seeds up high where they disperse more easily over a larger area.
Others, trees with more showy flowers, depend on insect pollinators -- flies, bees, and beetles. These flowers are generally aromatic (think of the linden tree) or showy, have smaller amounts of sticky pollen, and usually produce nectar as well. These flower characteristics attract pollinators that move from flower to flower as they feed or collect nectar. Tulip poplar, which produces flowers after leafing out, has a very pretty flower designed to attract pollinators. Some trees rely on birds to pollinate their flowers. Like insect pollinated trees, these trees have showier flowers, but are most often yellow or red in color to attract specific bird species.
So as you're, perhaps, blowing your nose, examine the tree flowers in your neighborhood more closely. Most people tend to focus on the larger more showy flowers. However if you take the time and look there are some amazing things happening in the forest. Whole hillsides of tree flowers are appearing across the state. Their color, although subtle, can rival the autumn splashes in our landscapes. And when you look closely, the detail and beauty of many of our tree flowers are absolutely amazing. From their tiny flowers, great trees can grow.
The Pennsylvania Forest Stewardship Program provides publications on a variety of topics related to woodland management for private landowners. For a list of free publications, call 1-800-235-WISE (toll-free), send e-mail to , or write to: Forest Stewardship Program, Forest Resources Extension, The Pennsylvania State University, 320 Forest Resources Building, University Park, PA 16802. The Pennsylvania Bureau of Forestry and USDA Forest Service, in partnership with the Penn State's Forest Resources Extension, sponsor the Forest Stewardship Program in Pennsylvania.
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