Journal of Student Research 2023

Journal of Student Research

16

Discussion Our study revealed differences between the planted tamarack stand at the Downsville Wetland and the natural tamarack stand at Muddy Creek State Natural Area. Muddy Creek plots were densely vegetated, with an understory made up of alder ( Alnus sp .) and poison sumac ( Toxicodendron vernix ), and with codominance in the overstory between black ash ( Fraxinus nigra ) and tamarack. Tamarack density at the site in Downsville was greater. It is likely the NRCS planted tamarack saplings densely because they knew not many would survive the juvenile stage. The mass planting of saplings could increase the chances for successful re-establishment. The plots were otherwise mostly depauperate of non-tamarack woody species. The lack of non-tamarack woody species could be related to the site’s previous agricultural use. Lastly, Muddy Creek had consistent standing water throughout the site, whereas the Downsville Wetland had no observable standing water. Although non-significant, our data hinted that tamarack size and water level may have a negative relationship, which is consistent with other studies (Evans et al., 2016; Farrar, 1995). The microtopography of each site was quite different. Muddy Creek had hummock-hollow microtopography, with tamaracks growing atop the hummocks and standing water in the surrounding hollows. The Downsville Wetland site was flat, without any noticeable hummock-hollow microtopography because the tamaracks there were planted in an old crop field. Mechanically reproducing hummock-hollow microtopography has shown to increase the recruitment of trees species faster than not doing anything on sites that have lost their microtopography (Filicetti et al., 2019). Overall, the distribution of tamarack size was narrower at the Downsville Wetland than at Muddy Creek, likely due to the young nature of the Downsville Wetland planting compared to the naturally existing forest at Muddy Creek. As hypothesized, the planted tamarack stand at the Downsville Wetland was more consistent in size compared to the natural tamarack stand at Muddy Creek. Additionally, Muddy Creek had very few individuals with a DBH less than 5 cm, which may indicate poor recruitment, despite the ubiquitous presence of cones in all sample plots. The Downsville Wetland did have a much higher count of smaller individuals, which is likely due to them not having grown much since their initial planting 7 years ago. Therefore, the number of individuals with a DBH less than 5 cm may be a poor indicator of recruitment. About 90% of the measured tamarack at the Downsville Wetland had cones, which indicates to us that they have reached reproductive maturity and are capable of recruiting. Our initial observations indicate that the stand has yet to start recruiting because only about 5% of all measured tamaracks had a DBH less than 2 cm. Further inventory and future comparison to our baseline data will be needed to accurately determine whether the stand is recruiting or not. Our results align with the existing literature that tamaracks are early successional species that colonize the edges of wet habitats. Even though tamaracks prefer drier soils (Farrar, 1995), they are often associated with wetlands because they cannot compete with other species, such as black spruce ( Picea mariana ), on drier soils. The density of other species in the understory at Muddy Creek may shade out any potential tamarack recruits and could be why the tamaracks are only seen as