## 4 Conclusions and Summary  
Our findings suggest that investments in black spruce regeneration for timber production in Ontario are relatively unattractive without introducing financial benefits related to carbon sequestration. This underlines the importance of appropriate carbon pricing policies for making slow-growing tree species a more attractive economically renewable resource [63]. The current work contributes to the ongoing effort to identify the effectiveness of particular carbon sequestration prices and projects in forest management. Our results are portrayed spatially, which is often overlooked in economic analyses. Non-spatial analyses often apply average values over large areas, thus ignoring significant geographic variation of key biological and financial factors. This can be problematic because climate change is likely to affect ecosystems at multiple spatial scales--from local to regional to global. Our use of GCM-derived NPP values and climate-driven yield equations allowed us to present results spatially--albeit at a relatively low resolution--and thus we were able to distinguish regions where black spruce regeneration investment should be most attractive. A significant aspect of this study is that it incorporates inter-annual future climate variability into the growth and yield model, which in principle allows for more realistic growth estimates. Past studies have utilized generalized forest growth and yield curves where seasonal and inter-annual climate variability are ignored [6; 7; 8]. Interestingly, our findings suggest that the range of black spruce growth and yield estimates for the end of the current century using annual future climate inputs do not vary substantially from those obtained using standard curves [64]. We do note, however, the issue of predicting future forest productivity under a changing climate is complex and requires further research, and is the subject of significant ongoing research. Further research is required to quantify additional risk factors associated with investments in forest regeneration. In our study, risk factors such as wildfire, disease outbreaks, or drought were not explicitly included in the economic calculus (which was done at the stand level). However, while the inclusion of such factors would help to improve future estimates of the economic values associated with forest regeneration, the general result of shortening rotations with increased risk is well known. [PERSON] [65] reported that, when probabilistic fire occurrence was incorporated into a stochastic forest stand rotation model, it led to shorter rotation intervals. [PERSON] et al. [66] also reported a reduction in rotation length with increasing fire probability, but noted that this reduction could be offset by the introduction of a carbon pricing system. Inclusion of climate change-modified forest fire risk would be a useful addition, because fire represents a major disturbance in the Canadian boreal forest that could impact large-scale patterns in biodiversity, carbon, vegetation, and forest management strategies [66; 67]. There are many uncertainties involved in this work. Our sensitivity analyses have attempted to explore some of the implications of this uncertainty as it relates to the underlying economic parameters; however, there is likely to remain significant uncertainty regarding the future growth of forests in general--with black spruce being a particularly important boreal species. Our use of GCM-based NPP-modifiers in combination with empirical yield equations represents a novel approach for incorporating climate change into future estimates of forest productivity. Ongoing efforts should continue to incorporate new insights into modelling future growth and yield and related economic values as they become available. We acknowledge funding provided by the National Sciences and Engineering Research Council (NSERC) of Canada through Discovery and Strategic grants and Ontario Ministry of Environment and Climate Change (MOECC).