Trees

Tree City USA

The City of Pleasant Hill has been a recognized “Tree City USA” community since 2003. The national Tree City USA program is the framework for community forestry management for cities and towns across America, recognizing efforts of the continuous and systematic management of urban trees. The City received this recognition by demonstrating a commitment to caring for and managing our public trees.

The city has also been received a Tree City USA Growth Award for six years, showing substantial improvement to the community’s urban forest by establishing a city arborist, developing a tree inventory, improving tree protection & preservation policies and practices, and hosting community education and outreach programs.

Trees on Public Property

If you have concerns about conditions, maintenance, the safety of trees at city parks, or on city right-of-way, contact Heath Ellis with Parks & Recreation at hellis@pleasanthilliowa.org or 515-309-0049.

Emerald Ash Borer

Emerald Ash Borer (EAB), an invasive beetle that kills all species of ash trees, has been confirmed in Polk County. It is native to Asia and was likely introduced into North America via cargo ships or planes. The beetle is bright metallic green in color and is visible to the naked eye, but is about the size of Abraham Lincoln’s head on a penny. The adult beetles eat ash foliage but cause little damage to the tree. It is the larvae that cause destruction. Larvae feed on the inner bark of ash trees, preventing delivery of water and nutrients to the tree, causing it to die.

Emerging Threats to Trees

EAB is only one of several other emerging threats to Iowa’s forest communities. In 2013, the DNR identified five key pests that have emerged and created a severe threat to Iowa’s native woodlands and community trees. The key pests identified in addition to EAB are:

Gypsy Moth - Feeds on over 300 species of tree leaves during the summer growing season.
Bur Oak Blight (BOB Tubakia spp.) – A newly named disease that can cause severe defoliation, leading to mortality of branches or entire trees, caused by a species of the fungus Tubakia.
Thousand Cankers Disease of Black Walnut (TCD) – A walnut twig beetle (Pityophthorus juglandis) that carries a fungus (Geosmithia morbida) spread as the beetle tunnels through tree tissues. Some experts believe TCD has the potential to decimate black walnut trees in the same way Dutch elm disease and emerald ash borer has destroyed their hosts.
Asian Longhorned Beetle (ALB) – Exotic pest native to China. The larva of this beetle kills trees by tunneling through the tree, which girdles stems and branches. The beetle prefers to attack maple species (Acer spp.). In some cases, they will also attack birch, elm, horsechestnut, and Ohio buckeye.

Proper woodland and community tree management is the best defense against these threats. The best insurance is to maintain a diversity of tree species; while assuring an appropriate number of trees are growing on each acre. The best management tool is for communities to create diversity by not having more than 10 percent of any one species represented.

Private Ash Tree in Pleasant Hill

In 2008, Parks and Recreation conducted a community ash tree inventory sampling. An estimated 920 ash trees are located on private property in Pleasant Hill (excluding commercial sites). The diameter-at-breast-height (DBH) of these ash trees vary upon location in the city.

Approximately 773 ash trees with DBH between 12 and 18 inches are primarily located south of University Avenue and west of Highway 65.
Approximately 143 ash trees (with smaller DBH) are in the newer developments of the city.
An estimated cost of tree removal and replacement ranges from $500 to $2,000, depending on size and location.

Plant Some Shade

Each spring and fall the Iowa DNR and MidAmerican Energy sponsor the “Plant Some Shade” tree distribution program available to residents with a diverse selection of high-quality nursery trees at a reduced price.

Public Ash Trees in Pleasant Hill

Inventory of ash tree's on public property was conducted by city staff in 2008. The city had 48 ash trees averaging 16-inch DBH. The majority of these 22 trees were located in Sunrise Park and Oakwood Cemetery. In preparation for an EAB infestation, the city has incrementally removed three ash trees per year since 2008. As of 2016, there are 24 ash trees remaining on the public property.

Other Resources

A variety of resources are available to assist residents in managing trees. Follow the links below for additional information.

Tree Benefits

22 Benefits of Urban Street Trees: Facts, figures and traffic studies detail the benefits of urban street trees.
Community Benefits from Public Trees in Iowa: Trees provide benefits and are an investment in the future of communities.

Trees and Natural Areas

Sustainable Urban Forestry in Pleasant Hill: The benefits of sustainable urban forestry within communities.
Natural Area Preservation: Learn how to identify, protect and restore natural areas within a community.
Tree Inventory: Learn about the health and population of Iowa's public trees.

Tree Care Resources

Young Tree Pruning Program: Learn the proper ways to develop a preventive pruning program for young trees.
Woodland Improvement and Crop Trees: Learn how healthy woodlands provide multiple benefits through stewardship.
Tree Pruning Cue Card: Learn how to appropriately prune crowns and roots so they are stable and healthy.
Pruning Established Trees Cue Card: Learn how to prune established trees to develop and maintain a dominant leader with branches.
Pruning at Planting Cue Card: Learn how to prune trees upon planting to correct poor structure by shortening upright stems.
How to Properly Prune Fruit Trees: Watch a video to learn why fruit trees are pruned to cut out cellulose (wood) so the tree doesn't put its energy into it by maintaining and producing branches but instead puts energy into producing carbohydrates in the form of fruit (fruit sugars).
Training Young Trees: Watch a video to learn why trees are assets, how they provide value to your property and why it's important for early structural training.