Forest Restoration in Campgrounds at Kings Canyon National Park, California

Abstract

Intensive campground use at the Grant Grove area of Kings Canyon National Park, California, has compacted the soil and left areas without understory vegetation or tree recruitment. To better inform the restoration of these sites after closure, we tested natural regeneration potential and planting and soil restoration methods. The tested methods included planting with container stock and direct seeding, fencing, and soil treatments of tilling, mulching, and gypsum and humus additions. Container stock had high survivorship (69–100%), while germination and survival from direct seeding was low (0.6–4.1%). Wood chip mulch was beneficial to planting woody species, but detrimental to resident herbaceous species. Plots treated with tilling and gypsum, and humus amendments exhibited highest growth rates of container stock and greatest herbaceous species richness and cover. However, tilling without the other soil treatments reduced herbaceous cover and seedling recruitment (natural and sown). In tilled plots, gypsum treatments and humus treatments often had neutral or detrimental effects individually, but their combination greatly increased the success of direct seeding, growth of container stock, and herbaceous cover and richness. Fencing increased volunteer tree recruitment tenfold compared to outside the plots. Some treatments in this study were beneficial to species of one morphological group but detrimental to another.