The city of Yankton soon celebrates Arbor Day. Urban forestry staff emphasizes the diversity of trees matched to growing sites and their care year-round, earning a 2023 Tree City USA designation by the Arbor Day Foundation in Nebraska. Nearby, Vermillion also meets the 2023 Tree City USA standards. Planting a tree is often part of an individual or organized Arbor Day celebration.
After a long winter, a walk among the trees beginning to leaf out at Lewis & Clark Recreation Area is a welcome lift. Trees will soon wear the green haze of early spring.
At the state park, cottonwood trees (Populus deltoides) get extra care and soil moisture from the Missouri River, even during drought. Some of the mighty trees are in bloom. This dioecious female tree has yellow-green flower catkins beginning to open. Catkins of a male tree are reddish purple.
A single female tree can produce 40 million seeds on cotton-like strands in summer. Conditions for seeds to germinate and grow are very specific, however.
North at McCrory Gardens in Brookings, the Cornelian cherry trees are beginning to bloom. They have often begun bloom between March 21st and May 5th, another sign of late spring if needed.
Nationwide, the Arbor Day celebration will be offset by concerns that since 2000, 109.4 million acres of tree cover have been lost in the United States. In his Press & Dakotan Editorial on April 25th, Kelly Hertz referred to the data compiled by Global Forest Watch World for Earth Day. Their data shows South Dakota has lost 24% of its tree cover since 2000.
Hertz pointed to the loss of forest trees in the state as a massive loss of wildlife habitat, loss of carbon dioxide storage, and loss of water and soil quality impact for all. With more grassland than trees in recent centuries, South Dakota has lost millions of forest trees to the mountain pine beetle infestation and drought in the Black Hills since 2000. Other tree cover losses in the state have included the removal of trees for cropland and additional development and invasive tree removal.
The increasing Emerald Ash Borer infestation is now documented in Lincoln, Minnehaha, and Union counties. Ash trees that will be eventually killed within about ten years of infestation, if not treated, are common throughout the state. Community efforts such as achieving tree city designation by the Arbor Day Foundation is a positive step among many needed.
So far, the closest, known, and local Emerald Ash Borer (EAB) infestation is in Dakota Dunes, about thirty miles east of Vermillion, according to Dr. John Ball, SDSU Professor, SDSU Extension Forestry Specialist, and SD Dept. of Agriculture and Natural Resources Forest Health Specialist. He recommends beginning ash tree treatments of select ash trees within 15 miles of an infestation, with an estimated EAB infestation growth about a year away.
Ball says that the adult EABs begin to emerge from beneath the bark of ash trees about late May. If ash trees are treated, the optimal time is from leafing out to early June. The treatment kills the adults that lay eggs and larvae in the summer. After EAB kills all the untreated ash trees, the EAB feeds, and shelters in new ash saplings, so treatments need to continue.
Search Dr. Ball’s “Tree Pest Alert” for April 19th at www.extension.sdstate.edu for more information and tree pest updates over the year.
If you plan to plant your Arbor Day tree, Ball suggests that it’s better to wait this late spring until the soil temperature reaches 60 degrees F. to allow for root growth. You will see farmers in the field about then. Many options on the Arbor Day website. www.arborday.org