Overstorey density influence on the height of Picea abies regeneration in northern Sweden

Natural Regeneration in a Multi-Layered Pinus sylvestris-Picea abies Forest after Target Diameter Harvest and Soil Scarification

“…However, the absolute height growth of all seedlings was less than previously reported for advanced regeneration under shelterwood and in stands under transformation towards more heterogeneous stand structure [10,13,14,51]. On the other hand, the magnitude was larger than observed for newly established seedlings under shelterwood [8,9] and in boreal Norway spruce single-tree selection stands [4,5,53]. Only a southern site in central Sweden [4] showed comparable annual height growth rates that ranged from 1-19 cm on average.…”

“…In order to promote more heterogeneous stand structures and to obtain more resilient, multifunctional forest ecosystems, management approaches are required that complement the prevailing systems of even-aged silviculture [3]. Some alternative management approaches such as single-tree selection in boreal Norway spruce stands and diameter limited cutting with enrichment planting in mature coniferous stands have been examined in northern and central Sweden [4][5][6][7] while the options to apply natural regeneration in multi-layered stands have rarely been studied in southern Sweden. Potential stand development trajectories including regeneration and ingrowth dynamics thus are difficult to predict.…”

Comparing individual-tree approaches for predicting height growth of underplanted seedlings

“…Basal diameter measured at the ground line is a metric commonly related to seedling response following silvicultural activities, and related findings support the positive association between seedling size and growth (Loftis 1990;Spetich et al 2002;Chrimes and Nilson 2005). The importance of seedling diameter as a growth predictor is generally attributed to the high correlation Initial seedling diameter and canopy cover array used to estimate height growth trends fall within the study's observed data range between a seedling's diameter and its root system size (Dey and Parker 1997).…”

“…Area-wide measures of canopy structure sampled at the stand or plot have been used to predict seedling growth (Brandeis et al 2001;Chrimes and Nilson 2005;Lin et al 2012). Other research has predicted growth using point-based metrics of canopy structure observed at each seedling (Jain et al 2004;Krueger et al 2007).…”

“…Much of this research has focused on measures of canopy structure that are correlated with understory light availability, and seedling growth is often predicted using variables such as canopy closure (Brandeis et al 2001;Jain et al 2004;Chrimes and Nilson 2005;Angell et al 2014) and basal area (Mitchell 2001;Krueger et al 2007;Angell et al 2014). Because vertical structure has also been found to influence the understory growth environment (Valladares 1999;Parker et al 2002;Comeau and Heineman 2003;Comeau et al 2006), it might reasonably be expected that seedling growth and mortality would also be related to the vertical distance from the ground to the forest canopy overhead.…”