ABSTRACT
There is a pressing global requirement to combat the conversion of natural habitats into agricultural land or degradation of forests, which threatens biodiversity and erodes environmental services, and contributes to climate change. It has been estimated that forest landscape restoration may be a potential option for more than two billion ha worldwide (Minnemayer et al. 2011). The tree regeneration phase offers the best opportunity to change tree species and forest ecosystem structure, and this period is therefore an important initial step in restoration of forests. Regeneration can be achieved through natural or articial (planting and direct seeding) means, but planting trees is almost always a key component of restoration activities (Oliet and Jacobs 2012; Stanturf et al. 2014). However, a particular challenge of the regeneration phase is that it is often expensive, and costs for restoration usually increase with the degree of ecosystem degradation (Stanturf et al. 2001; Birch et al. 2010). Thus, it is important to achieve regeneration success, but unless steps are taken to control competing vegetation and improve soil conditions, articial or natural forest regeneration often results in unacceptably poor seedling survival and growth, (e.g., Balandier et al. 2006; Löf et al. 2012), which in turn may result in substantial economic losses. Site preparation techniques are important tools to counteract this.
