## 3 Results and Discussion
### Influence of Climate Change on Expected Ecosystem Performance
The expected shift in fire frequency and severity could result in a novel ecosystem dominated by black spruce, aspen, and birch [31], presumably increasing average EEP due to a longer successional duration and greater spatial coverage of deciduous forest. The magnitude of increased ecosystem performance increases also suggests that deciduous species may mix with stands presently dominated by less productive coniferous species in unburned areas. Additionally, since deciduous stands tend to burn less often than coniferous ones, they are more likely to reach maturity and peak performance, and provide a negative feedback to increasing fire frequency. Due to a shorter foliar period, the duration of carbon accumulation in boreal deciduous stands is also shorter, but more intense than in coniferous stands with an average Net Ecosystem Exchange (NEE) two to three times greater than coniferous stands in June and July [36]. The GPP in both coniferous and deciduous stands in interior Alaska responded positively to spring (April-June) warming, with a 16% and 74% increase, respectively, during this portion of the growing season [36]. Late summer droughts are associated with a reduction in GPP and increase in respiration in both deciduous and coniferous stands; however, both can still serve as a net growing season carbon sink when affected by short-term severe drought (_i.e._, 2004) [35,36]. The impacts of longer duration droughts are less clear. Limitations with statistical model future projections (as well as some process-based models) are related to changing conditions, interactions, or feedbacks that may not be included in the model, such as increasing greenhouse gas (GHG) concentration impacts on vegetation, permafrost melting and associated potential changes of subsurface water flows [101] or terrain subsidence, emission of permafrost carbon, and future fire impacts on permafrost, carbon emission, and forest composition. These factors, feedbacks, and interactions were not explicitly included in this modeling effort and the only variable that was allowed to change for the future mapping was climate. The assumption was that the interactions that exist currently in the Yukon Basin would persist in a similar manner in the future. There are imperfections in all models and predicting the future has many unknowns and assumptions. The approach here is data-driven from a high number of observations through space and time and represents a different approach than classical mechanistic-based future predictions. Climate change is likely to influence future species dispersal, establishment, community structure, and ecosystem performance by increasing the area and frequency of fire [3,15,22], increasing the prevalence of insect defoliation and mortality [4,95], and increasing drought-induced mortality [18,19,21]. The altered future climate may impact the resilience of stands following fire, where the regrowth may not recover to its previous coniferous dominated state [8], possibly resulting in a deciduous-dominated climax community [16,33]. This in turn may affect soil organic layer thickness and permafrost [8]. The increased deciduous forest cover in the future may also regionally serve as a negative feedback to a warming climate, since it has a higher albedo than conifer forests and an evaporative cooling effect [13,91,102]. Considering the above factors, actual net changes to ecosystem performance may differ from our results (Figure 5) due to concomitant changes in disturbance regimes and species composition [1,20,95], and these changes may be abrupt [13]. Moreover, the performance response to climate change may change or reverse after environmental thresholds have been surpassed [16].