Tree direct seeding and natural volunteer seeding can be an effective means of reforesting sites. This site was dominated by reed canary grass and was a former hay field. The site was direct seeded in the fall of 2017 after site prep to control competing vegetation.
Figure 1: Disked field just after fall planting
Acorns, walnuts, and dogwood seeds were planted while many light seeded floodplain trees naturally seeded themselves in from surrounding parent trees. The site was initially chemically (herbicide) and mechanically (disc) prepared to create bare mineral soil conditions. Acorns and walnuts were planted to a depth of 2-3" while dogwood seeds were broadcast directly onto prepared soil. During the growing season following planting, herbicides were used to control competing vegetation. During the second growing season 1660 stems/acre were recorded, 350 of which originated from planted seed.
River or stream name: Root River
River or stream type: Minor river
Floodplain or terrace: Terrace
Floodplain topographic position: Ridge and swale
The primary objective here is to establish a fully to nearly fully stocked stand of floodplain forest with both light seeded maple/cottonwood and hard mast components. Reed canary grass should be controlled to allow for tree and native understory establishment.
Pre-treatment stand description and condition
Stand establishment and management history:
The stand occurs in a former hay field that was dominated by reed canary grass. Aside from being cut for hay when dry conditions allowed, the field was utilized for hunting ducks during stopover periods. While the field was a near monoculture, scattered native forbs did exist, however reed canary comprised at least 98% of the cover. The stand was direct seeded in 2017.
Pre-treatment species composition:
Near reed canary grass monoculture, estimated at 98% of vegetative cover, with few scattered natives.
Pre-treatment growth and stocking:
The site was not forested prior to the treatment.
Establish native floodplain forest cover.
- Create bare mineral soil conditions by mowing and subsequent herbicide applications and discing (see next section).
- Direct seed bur oak, swamp oak, red oak, black walnut, red osier dogwood and silky dogwood.
- Allow supplemental natural regeneration from volunteer seeds.
- Maintain planted and naturally occuring trees with herbicide to release from competition.
What actually happened during the treatment
In early June of 2017 the site was mowed as low as possible using a tractor mounted brush hog in the summer of 2017. The site was allowed to green up to a height of 12 inches and was then chemically treated with 2 quarts per acre Rodeo in early July. In Early September the site was again treated with 2 quarts per acre Rodeo. In October 2017 the site was disked to break the soil, then direct seeded with hardwood seeds.
Bur oak, swamp white oak, and red oak were broadcast at a rate of 1.5 bushels per acre and black walnut at a rate of 8.2 bushels per acre. Once broadcast the hard mast was disked into the soil to a depth of 2-3 inches. Silky and red osier dogwood were broadcast directly onto the prepared soil surface at a rate of .7lbs/acre each
In June of 2018 the site was treated with transline at a rate of 1/3 pint/acre to manage broad-leafed weeds such as giant ragweed and stinging nettle. In the fall after the trees had gone dormant the site was treated with .5 oz/acre Oust to help control new reed canary seedlings in 2019.
Figure 2: Planting site in 2018, the year following seeding
In 2019 the stand was sampled to determine regeneration stocking. Tree heights were not recorded, only the presence of a tree stem. Tallied trees are as follows:
- 140 silver maple (Natural Regen)
- 180 swamp white oak (Direct Seeded)
- 520 box elder (Natural Regen)
- 10 black walnut (Direct Seeded)
- 580 cottonwood (Natural Regen)
- 0 red osier dogwood (Direct Seeded)
- 0 silky dogwood (Direct Seeded)
- 160 red oak (Direct Seeded)
- 70 ash (Natural Regen)
1660 total stems
Plans for future treatments
Approximately 100 containerized RPM trees have been planted throughout the site to further bolster the planting. The site will be monitored and competing vegetation will be managed as necessary. It is likely that no further management will be necessary as the young trees appear poised to recruit into the pole stage.
Costs and economic considerations
- Mowing: $85-110/acre/treatment
- Herbicide: $100-130/acre/treatment
- Direct seeding (seed and labor): $400/acre/treatment
Total cost: $585 - $800/acre including multiple herbicide treatments.
Walnut seeds were not husked which may have been part of the reason very few walnut were successful. If done again we would process and stratify the dogwood seed and hand sow in the spring following the initial planting. A light discing or packing of the dogwood seeds may have also helped them to take root.
Summary / lessons learned / additional thoughts
This treatment was successful in both regenerating native trees and enhancing native wildlife habitat. Through chemical and mechanical treatments we were able to drastically reduce the presence of reed canary grass and increase both native tree species as well as native forb species. The conversion was accomplished for approximately $900/acre after multiple treatments.
Trees that were manual seeded into the site are far outnumbered by trees that naturally seeded themselves into the site. We expect that some TSI will be necessary in the future to release the seeded trees from competition. Although oak species are more desirable here compared to naturally seeded trees, all trees will help deter reed canary grass from dominating the site.
Another approach to this type of work could be preparing the site both chemically and mechanically to achieve bare mineral soil, followed by a planting of bare root or containerized trees rather than direct seeding. Planting bare root trees could allow for greater recruitment and survival, however naturally regenerating trees may achieve a relatively fully stocked stand on their own. Managers should be conscious of their goals. In this case, native habitats are a higher priority than fully stocked timber stands.
Figure 3: Unmanaged reed canary on left, managed planting on right.