Case Studies Detail
Roadside Trees in Richmond, Virginia 2013-2019
This case study was carried out in collaboration with the Urban Forestry Department, City of Richmond, Virginia.
Richmond City performed a street tree planting project on Jefferson Davis Highway in 2012-2013. In August 2013, on the road medium of a block south of Maury Street, TreeDiaper® TD36 was installed and covered with mulch. Adding the mulch on the top of TreeDiaper® TD36 can prevent vandalism and keep the natural looking outside. On an adjacent road medium a block north of Maury Street, standard watering bags remained on the trees.
Annual natural precipitation in Richmond Virginia is generally above 40 inches. Seasonal drought occurred in July 2014 (~1" rainfall) and August 2016 (~1" rainfall) and severe winters occurred in 2013-2014 (-15°C) and 2014-2015 (-10°C). Since the installation of TreeDiaper® TD36 treemats and by the end of 2016, trees on the south side of Maury Street have not been provided any maintenance services such as watering and de-weeding (grass mowing around the trees were kept as normal). The north side of Maury Street received regular maintenance services.
Results
- Trees with TreeDiaper® Advanced Hydration System all survived and grew green and strong as of June 2017 as shown by Google Street View Images.
- Trees with standard watering bags died (July 2014, and were removed in April-July 2015 as demonstrated by the Google Street View Images.
- No maintenance was needed for trees with TreeDiaper® advanced hydration system during the testing period.
- Investment in trees (~$250/tree) from the City was saved by using TreeDiaper® advanced hydration system.
- The Soil Moisture under TreeDiaper® was much higher than those under watering bags (Figure 1)
- Soil temperature maintained a higher temperature during winter storms (Figure 2) and maintained at a cooler temperature during hot summer days (Figure 3).
- Cost comparison between TreeDiaper® TD36 and watering bags (based on reported watering frequency and associated watering truck, fuel, labor, and water costs) shows a clear difference (Figure 4).
NOTE #1: the trees installed with TreeDiaper® treemats on the road median are alive as of June 2019 according to Google Map. But they are not THRIVING. This is not unexpected. Road median is always a tough condition for trees. In addition, the soil in this particular site is very poor. It consists of 80% of debris from road construction that was covered with 1" of topsoil.
NOTE #2: In three weeks after TreeDiaper® treemats were installed, 30% were cut open by the lawnmowers. Knowing it is not practically possible to replace 30% every time they mow grass, we added more mulch and moved stakes that were in the center of the road medium to the edge of the road medium to keep lawnmowers away. The partially broken TreeDiaper® treemats continued to nurture these trees.
If you are interested in this study, you can view the Google Maps history by searching "Jefferson Davis Highway, Richmond, VA." Look for the intersection between Maury Street and Jefferson Davis Highway.
Google Maps view South Block with TreeDiaper®
Google Maps view of North Block with watering bags (only one was ever caught in camera, the others were installed and disappeared in between the visits by Google)
Figure 1. Soil moisture of TreeDiaper® mats compared to watering bags in the road median of Jefferson Davis Hwy, Richmond VA.
Figure 3. Soil temperatures (3" below soil surface) on in Taylor Park and Poor Farm Park of Hanover County and Jefferson Davis Highway of the City of Richmond in June-August 2014.
Figure 2. Soil temperatures (3" below soil surface) on Jefferson Davis Highway of City of Richmond in January-February 2014.
Figure 4. Cost Comparison of TreeDiaper® TD36R with Watering bags with reported watering frequencies of watering bags and the associated costs of equipment (watering tank, truck), fuel, labor, and water costs.