## 4 Breakout Sessions  
The summit's three breakout sessions were organized around AHB's work on feedstock production, fuels conversion, and markets and policy and reflect the organization the Northwest Advanced Renewables Alliance (NARA) 2017 USDA CAP survey (Feedstock, Processing, Economics, Sustainability) [33]. The AHB summit breakout sessions also closely paralleled the alcohol-to-jet fuel development goals of the Federal Alternative Jet Fuels Research and Development Strategy [1]. The objective of the sessions was to pinpoint, from an investor's perspective, drivers and barriers to commercializing biomass farms and biorefineries. Drivers uncovered in the NARA 2017 USDA CAP survey were: (1) government policy, (2) co-products, (3) reduction in carbon emissions, (4) volatility in oil pricing, (5) energy independence and security, and (6) rural economic development [33]. Barriers were: (1) High production cost (mostly associated with feedstock costs); (2) policy uncertainty; (3) competition with petroleum fuels; (4) capital availability; (5) technological availability; (6) cellulosic biofuels logistics; and (7) consistency of feedstock supply. These coincide remarkably well with the recommended priorities stemming from the second pertinent study, the Canadian Forest Service two-round Delphi survey [34]. These are listed in descending order of importance: (1) Develop the demand for short-rotation, intensive-culture (SRIC) biomass and services; (2) establish policies and programs promoting renewable fuels, bioproducts, and environmental services; (3) establish policies and programs promoting the application of SRIC; (4) establish policies and programs to reduce greenhouse gas emissions; (5) develop production technologies for SRIC; (6) develop conversion technologies for woody biomass. Feedstock Production--The panelist identified three priorities in improving returns from investments into growing and delivering biomass feedstock. First is improvement in breeding and selection to increase poplar per-hectare biomass yields by 20% in the near term through conventional breeding techniques; long-term potential is to double the biomass yields using molecular breeding tools to eliminate physiological constraints to biomass productivity [35]. Breeding for water use efficiency, was strongly recommended in the session as an essential imperative to the cultivation of lower quality and less costly lands that would move production costs to a more competitive position [36] (cultivation of under-utilized or non-productive lands using perennial energy crops is also key to exploiting carbon sequestration markets [37]). It was recognized that genetic modification has made great strides in yield improvement and drought tolerance, but commercialization of transgenic varieties may be problematic insofar as environmental certification agencies are concerned. Either concurrently or in place of genetic improvement, endophyte technology developed by AHB at the University of Washington and now commercialized by Intrinsyx Technologies was recommended to improve the water-use efficiency in existing commercial hybrid varieties. The panel also recognized variation in saccharification efficiency as an enormous opportunity to reduce the conversion costs through varietal selection using genomic tools. It is a priority of CBI at Oak Ridge National Laboratory to develop such varieties that undergo pre-treatment and hydrolysis with increased cost-effectiveness. Finally, the feedstock panel felt it important to reduce the cost of vegetation management particularly during the first cutting cycle. Second, the panel recognized that the environmental attributes of poplar production will immeasurably improve the feedstock production economics when effectively monetized. This may resolve the conflict between economic and ecological interests which is identified as one of the key limiting factors to the development of the bioenergy industry [18]. Chief among poplar's ecological attributes are water quality enhancement and carbon sequestration.