In order to understand the broader impacts of a large scale dispersal of A. macrophyllum into interior forests, it is important to consider its interactions with other species, ecosystem functions and the projections for other tree species in western North America. We must also consider that the predictions reflect suitable conditions for A. macrophyllum, and that other factors are likely to influence actual species dispersal across its suitable range. Forest management strategies are likely to influence whether the potential range is realized, and a changing climate may introduce secondary influences on the dispersal of A. macrophyllum that the model does not account for.
While we have a broad understanding of the functions A. macrophyllum has in coastal forests: its correlation with animal biodiversity (Hagar, 2007) increased soil nutrient content (Fried et al., 1990), and influence in soil hydrology (Hamdan & Schmidt, 2012); it is unclear how these functions will be realized in new habitat. We can expect that a presence of A. macrophyllum will change soil properties and ecosystem dynamics in areas it colonizes. However, interactions between this species and other ecosystem components, particularly where they are sufficiently different from the populations previously studied, are difficult to predict. It is possible that a presence of A. macrophyllum will have stabilizing effects on conifer populations, due to increases in soil nutrients from leaf litter. But its invasion could also threaten other vulnerable tree species, as well as species that it does not typically interact with in its current range.
There have been a number of studies demonstrating the vulnerability of many now dominant conifer species in the Pacific Northwest, and many of the most vulnerable species also have high economic value (Coops & Waring, 2011; Case & Lawler, 2016). Coops and Waring (2011) suggest that a broad-scale resorting of tree species is underway in the region, and this will fundamentally alter forest ecosystems. A. macrophyllum is uniquely positioned to thrive in these changing conditions: it can reproduce rapidly, and is often one of the first large tree species to colonize after disturbance (Fryer, 2011). We expect that the frequency and intensity of disturbances such as wildfire and flooding will continue to increase, and as the predicted range increases are along river valleys and in fire-prone areas of central Washington and Oregon, these processes could speed up the dispersal of A. macrophyllum.
Hagar (2007) asserts that forest managers today consider biodiversity and ecosystem function as important to overall forest health and productivity. However, many traditional forest management strategies included the elimination of broadleaf trees including A. macrophyllum (Swanson, 2005). Their presence has often been associated with increased mortality of conifers (Acer macrophyllum pursh, 2018; Hamdan & Schmidt, 2012) despite evidence that they serve an important role in creating hospitable soil conditions for conifer growth (Hamdan & Schmidt, 2012). Given the historical practice of deciduous tree removal and the increased risk to economically important species under climate change, forest managers may respond by artificially limiting the dispersal of broadleaf trees such as A. macrophyllum. The combined impact of increased disturbance from wildfire or flooding and forest management practices introduces considerable uncertainty that is extremely difficult to account for in any modelling framework.