Restoring forests: advances in techniques and theory

Abstract

IntroductionMuch of the past science of forest regeneration emphasized reforestation following timberharvest for industrial purposes. These research initiatives fostered groundbreakingadvances in our field. The establishment of a target seedling concept was developed inNorth America during the 1980’s and 1990’s (Rose et al. 1990; Colombo and Noland1997). Genetic improvements in wood quality and productivity of plantations have led tosubstantial gains in profitability (Ahtikoski et al. 2012). A vast amount of literature hasshown the complex interactions between forest vegetation management and seedlingresponses, underlining the need to untangle the multiple factors involved (Ammer et al.2011). Characterization of ecophysiological processes associated with resistance toplanting stress and early establishment in temperate and boreal forests (Duryea andMcClain 1984; Burdett 1990; Margolis and Brand 1990) has also shed light on the basis toimprove reforestation success by managing cultural variables during nursery productionand post-planting. Collectively, these contributions have greatly advanced the science andapplication of forest regeneration.In recent decades, however, a pronounced evolution has occurred whereby the focalpoint of many of today’s forest regeneration scientists has shifted prominently towardrestoration of harsh, degraded environments. Intensive management practices, such assurface mining and road construction, yield extremely harsh sites requiring restoration,demanding new seedling production and planting techniques (Badi´a et al. 2007; Bell andHobbs 2007; Salifu et al. 2008; Josa et al. 2012). Many areas, previously converted toagriculture, have since been afforested in developed countries by overcoming problemsassociated with years of cropping use, such as weed competition or soil compaction.