• Past, current, and future forest harvest and regeneration management in Interior Alaska boreal forest: adaptation under rapid climate change

      Morimoto, Miho; 森本未星; Juday, Glenn; Valentine, David; Huettman, Falk; Yarie, John; Barber, Valerie (2016-08)
      The Alaska boreal forest is largely ecologically intact and provides various services, but is experiencing rapid, mainly climate-driven changes, and thus adaptation is essential. Systematic forest harvest management has occurred in central Interior Alaska for about 40 years, and this period is used in this study to examine the essential elements of adaptive management: monitoring, evaluating, and adjusting. In chapter 1, I examine historical relationships between forest growth and removals in the study area. My result shows that forest harvest management has relied heavily on natural regeneration. The harvest level was much lower than the overall annual allowable cut (AAC) level in the last 40 years. However, harvest activities were concentrated in road-accessible areas and white spruce stands. In chapter 2, I evaluate whether state forest harvest units are adequately regenerated after a period of 10 to 40 years under the typical low-input management. The results indicate that post-harvest regeneration has been largely successful based on the state regeneration standard established under the Forest Practices Act and follows a similar successional pattern to that seen following fire. In chapter 3, I examine whether harvest type, site preparation method, and reforestation technique resulted in differences in forest regeneration. The results indicate that clearcutting and/or site preparation increased tree regeneration, basal area, and biomass when compared to partial harvest and/or no site preparation. Planting of white spruce may only be necessary in specific circumstances, such as years with no/low white spruce seed crop, landscapes depleted of seed trees, or when early spruce dominance of the site is desired. In chapter 4, I identify the effects of landscape and forest management predictors on post-harvest regeneration in the study area and build post-harvest regeneration scenarios under different management practices and levels of climate change. The results show that post-harvest regeneration is largely influenced by site-level environmental factors rather than management practices. Regeneration is projected to fail on many low elevation sites under the climate scenarios. As a result, forest management practices need to be adjusted specifically to the site and prepared for a climate regime shift. In chapter 5, I offer adaptive management approaches to prepare for the challenges of the future by synthesizing the knowledge and practices of the past, and the needs and challenges of today. Continued monitoring and evaluation is essential for adaptive management to be successful, particularly because of the short history of systematic forest harvest management in the study area. Some of the key forestry databases I analyzed need substantial improvement. However, this study provides the basis to build adaptive forest management for the first time in boreal Alaska, which requires adaptive approaches sooner than elsewhere due to rapid climate change now well underway.