Revegetating Blackwoods Campground, Acadia National Park: Emphasis on Natural Regeneration of Red Spruce and Balsam Fir

O'Brien, Cristin

ôBlackwoods Campground in Acadia National Park has declining vegetative understory, characterized by a lack of tree seedling recruitment and shrub populations. This project was embarked upon to identify limiting factors to tree seedling establishment and shrub survival. From these studies, management plans will be developed for revegetating the campground understory. To better understand the factors that inhibit successful seedling establishment, we investigated the effects of varying soil moisture levels on seed germination, seedling survival and seedling dry mass accumulation for red spruce and balsam fir. We also studied the effect of organic layer depth on seedling growth for both species. Our experimental results and observations indicate that a tree seedling population in the understory of Blackwoods Campground is attainable with natural seed inputs and current light levels, but that additional watering is required. Red spruce and balsam fir seed germination significantly decreased below a threshold of 25% soil moisture (based on soil moisture at field capacity). Moisture is critical for seedling establishment, especially for red spruce. Low root:shoot ratios resulting from the indeterminate growth habit of red spruce cause a decrease in drought resistance for seedlings older than two months of age. Watering is also necessary to promote successful root penetration through the organic horizon. We found that the organic layer in Blackwoods is an essential nutrient source for vegetation and that the thickness of the organic horizon does not inhibit seedling growth if the soil is kept moist. Both red spruce and balsam fir will maintain a presence in the campground with watering assistance, and protection from damaging behaviors from campers. In addition to studying tree seedling recruitment, we evaluated eleven native shrub species in very austere conditions for their suitability to plant at campsites within Loop A of Blackwoods Campground. One shrub of each species was planted at 22 campsite locations and monitored over two and a half years for growth and survival. Light measurements and soil samples were also collected. Analyses found no correlations between growth and edaphic factors for any species. Our final list of recommendations contains seven species that have either proven their vigor in natural stands throughout the campground, or proven their suitability by showing positive shoot growth and good health during this study. The recommended shrubs are gray dogwood, winterberry holly, American elderberry, Meadowsweet, dwarf bushhoneysuckle, sweet fern, and northern bayberry.ö There is a species list of tree and shrub species found within the Black woods Campground when surveyed in the fall of 2001 (Table 11.) /STUDY LOCATIONS:/ /ACADIA NATIONAL PARK/MOUNT DESERT ISLAND/ blackwoods campground /