Townsend’s Community Forest Part 2
 | Author:
Patrick Plantenberg, Tree Board Chair
Townsend Tree Board Chair, Townsend Rotary Club |
Townsend’s Community Forest Part 2
Pat Plantenberg
Note: This is the second in a series of articles from the Townsend Tree Board reporting on the status of the community forest in Townsend.
Last week, we learned that the Townsend Tree Board has conducted four tree inventories on public property in 1990, 2005, 2011, and 2020. The 2020 inventory uses the state of Montana Department of Natural Resources and Conservation TreeKeeper inventory software system and tree data has been updated regularly as changes occur. These updates are significant to keep the data on the community forest up to date.
Townsend’s Landscape Character
The City of Townsend lies on a nearly level old stream terrace of the Missouri River. Like all alluvial soils, soil characteristics vary locally depending on river deposition patterns. Most soils have a thin upper layer 20 to 40 inches thick consisting of gravely loamy sand to clay loam. Subsoil consists of sand and gravel and in a few areas clay. Soils may be affected by calcium carbonate salts and alkalinity (a high pH) which limit water infiltration, water holding capacity, and availability of micro- and macronutrients. Compaction and construction impacts in disturbed areas make it important to dig tree planting holes at least twice as wide as the tree roots but don’t dig holes deeper than the tree roots to avoid planting too deep-tree roots need oxygen! Always plant trees in our native soil. Just remove rocks over 1” in diameter. The addition of soil amendments is not generally recommended. The Tree Board does use some elemental sulfur, a little wood-based compost, an iron additive, and a little organic fertilizer when we plant.
Townsend has a modified continental climate. Invasion of Pacific Ocean air masses, drainage of cool air into the valleys from surrounding mountains, and the protecting mountains shield in all directions combine to make temperature changes somewhat smaller than a true continental climate. During winter, a few invasions of cold Arctic air occur which drop the temperatures well below zero. Trees planted in Townsend, generally, must be hardy in USDA Hardiness Zones 2-4. The frost-free growing season ranges from 100 to 110 days long. Townsend lies in the rain shadow of the Elkhorn Mountains to the west. Average precipitation is 12 inches, three-fourths of this falls between April and September. This climate does not lend itself to trees growing naturally in Townsend. All trees have died around abandoned homesteads as soon as supplemental water ceased. All trees planted in Townsend need supplemental water!
Townsend had a population of 1,878 (2011 Census data). Based on the latest 2020 data from the US census, the current population of Townsend is 2,152 https://www.biggestuscities.com/city/townsend-montana). Townsend has grown 15.4% since 2000 and the local area continues to grow rapidly.
Townsend is served by two main business districts, one east-west along Broadway or Montana Highway 12 and the other north-south along Front Street or US Highway 287 to the south of Broadway and US Highways 12 and 287 to the north of Broadway. The residential areas lie north and south of Broadway and east of Front Street. There are four main city parks: Heritage Fun Park, Holloway Park, McCarthy Park, and Veterans’ Memorial Park. These highway corridors, residential streets, and parks are the focus of tree planting on public property.
Why is it important to manage Townsend’s community forest?
With the landscape setting described above, what trees would exist in this area, if Townsend shut down tomorrow and everyone left the community? As mentioned above, almost all tree species in Townsend would die without additional water. Without active management, the community forest would soon be dominated by a limited number of volunteer species adapted to our dry climate such as introduced shelterbelt species like Siberian elm (Ulmus pumila), and Russian olive (Elaeagnus angustifolia). Other volunteers in town include green ash (Fraxinus pennsylvanica), boxelder (Acer negundo), and Rocky Mountain Juniper (Juniperus scopulorum). These five species are common volunteers from seed in alleys interfering with the city garbage trucks, and volunteer under fences and next to buildings. The Tree Board removes hundreds of these volunteers each year.
The most common tree species volunteering in our community is the Siberian elm, a very hardy Zone 2 tree. Siberian elm is an important shade tree in Montana, but it is a prolific seed producer and sheds limbs regularly. In 1984 and 2009, Siberian elms in Townsend had up to 1/3 of their canopies die back from spring and fall extreme weather events. These trees largely have naturally recovered from these canopy losses. Pruning by the Tree Board has sped up the recovery of the Siberian elm canopy in the last 15 years. Most Siberian elms have been removed as boulevard trees in Townsend. Siberian elm is not being planted anymore.
Russian Olive has been classified as a noxious weed in Montana as it is spreading prolifically in riparian areas along waterways across Montana. It is displacing native riparian vegetation. It can no longer be planted in Montana. We only have a few boulevard trees that are Russian olives. The Tree Board removes all Russian olive volunteers when encountered.
Green ash was heavily planted in Montana cities and is our most common street tree. The female green ash trees are prolific seed producers like Siberian elm. The Tree Board is not planting any green ash or white ash trees as the emerald ash borer is headed our way and when it arrives it kills 99.9% of the ash trees. Hopefully, an emerald ash borer-resistant cultivar will be developed in the future.
Boxelder is one of our two native maple trees in Montana. Like green ash, they also have male and female trees. The female trees attract boxelder bugs. The Tree Board does not plant female boxelder trees. A new cultivar called ‘Sensation’ Boxelder is a male cultivar that does not produce seeds and does not attract boxelder bugs. It does well in Townsend.
Rocky Mountain Juniper is a native small tree common in the foothills around Townsend. It is not a shade tree so the Tree Board only plants it in locations where small trees are needed, like under powerlines.
We need to manage the community forest to limit these undesirable volunteers and to plant desirable species in desirable locations.
Next week, we will review how the number of public trees has changed since 1990.
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