Townsend’s Community Forest Part 6
 | Author:
Patrick Plantenberg, Tree Board Chair
Townsend Tree Board Chair, Townsend Rotary Club |
Townsend’s Community Forest Part 6 Patrick Plantenberg Tree Board Chair Note: This is the sixth in a series of articles from the Townsend Tree Board reporting on the status of the community forest in Townsend.
Last week, we discussed how we have reduced the dominance of the species that dominated our community forest in 1990. Urban tree planting guidelines recommend that no single tree species should represent more than 10 percent of the tree population. Townsend has made significant progress in 33 years to achieve proper tree species planting guidelines.
This week we will discuss urban forestry guidelines for genera and families and how Townsend is doing in meeting those guidelines. Townsend Public Tree Genera and Families Over Recommended Guidelines.
In botany, trees are split into families largely based on the characteristics of the flowers. Families are then divided into genera and finally species. Urban forest tree planting guidelines recommend that no single genus or family should equal more than 20 percent of the tree population. This diversification will be more aesthetically pleasing and will minimize future insect, disease, and weather damage.
Of the genera inventoried, two genera, the ash genus (Fraxinus spp.) at 48% and the elm genus (Ulmus spp.) at 22%, exceeded the 20% limit in 1990 (Figure 1). By 2005, ash was the only genus exceeding the 20% threshold at 24%. By 2011, the ash genus had dropped to 20%. No other genus exceeded 12% in 2011. In 2020, the ash genus had dropped to 18%. No other genus exceeded 11% in 2020.
Of the plant families inventoried, two large, first-generation tree families, the ash family (represented by Fraxinus spp. in Townsend) at 48% and the elm family (represented by Ulmus spp. In Townsend) at 22%, exceeded the 20% limit in 1990 (Figure 2). By 2005, the ash family was the only family exceeding the 20% guideline at 24%. By 2011, the ash family had dropped to 20%. The ash family continues to drop in dominance as ash trees are being removed because of the threat of the emerald ash borer and members of other tree families are planted. In contrast, the diverse small tree-dominated rose family (represented by hawthorns (Crataegus spp.), apples (Malus spp.), cherries and chokecherries (Prunus spp.), pears (Pyrus spp.), and mountain ash (Sorbus spp.) genera) had increased to 21% by 2011. Many city tree managers forget about the diversity of the genera in the rose family. In 2020, the popularity of the rose family flowering tree genera increased the rose family total to 22% of the urban tree population.
This spring, the rose family put on a spectacular display dominated by spring snow crabapples, Canada red chokecherries, and pink flowering crabapples.
Normally, a late frost in our area limits the flower production of the rose family. Last year, we saw a tremendous increase in rose family health problems, especially fireblight. Fireblight is a bacterium that can eventually kill the affected tree if the infected branches are not pruned off and/or the trees are not treated chemically.
Mountain ash and spring snow crabapples showed the most increase in fireblight infections in 2022. The Tree Board just completed spraying over 200 trees in the rose family to help control fireblight. These trees will be sprayed again this fall as the leaves start their fall coloration.
Several fireblight-infected rose family trees in Townsend are systematically being removed as they start to look bad. For example, two flowering pear trees were removed in front of the Broadwater Detention Center last Friday.
The Tree Board is not planting any more flowering pears and mountain ash species because of their susceptibility to fireblight. And the Tree Board is only planting two species of crabapples that have excellent fireblight resistance. Any questions about fireblight, please call Patrick Plantenberg, Tree Board Chair, at 406-431-4615.
Next week, we will discuss the condition of the trees in our urban forest in Townsend over the last 33 years.
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