Establishment and growth of native hardwood and conifer seedlings underplanted in thinned Douglas-fir stands

Silviculture for old-growth attributes

“…However, after longer periods without larger disturbances, understorey species composition in thinned stands becomes more similar to old-growth than in unthinned stands (Bailey and Tappeiner, 1998;Lindh and Muir, 2004). This is probably due to the recovery of the overstorey cover after thinning (Davis et al, 2007;Maas-Hebner et al, 2005), which has been shown to reach overstorey cover levels (He and Barclay, 2000) and leaf areas (Bailey and Tappeiner, 1998) similar to unthinned and old-growth stands within two to three decades. The resulting reduction in light levels (Beaudet et al, 2004) and belowground resources (Riegel et al, 1995) in conjunction with plant interactions among understorey plants, such as competitive and facilitative processes (Thomas et al, 1999;Delagrange et al, 2006) are most likely responsible for the shift in species composition.…”

Density management and biodiversity in young Douglas-fir forests: Challenges of managing across scales

“…Survival and growth of regenerating conifers are strongly related to the understory light levels (Gray and Spies, 1996) and provide a good example of how creating spatial diversity in overstories may have long-term effects. Regeneration of shade-intolerant conifers is not likely in small gaps (<0.1 ha) or in the understory except in widely spaced stands (Maas-Hebner et al, 2005). Shade-tolerant species can survive in small gaps or under dense canopies, but will not grow quickly under these conditions (Taylor, 1990).…”

Roles of thinning intensity in hardwood recruitment and diversity in a conifer, Criptomeria japonica plantation: A 5-year demographic study

“…Parker et al, 2001;Maas-Hebner et al, 2005). To preserve genetic diversity and reduce management costs, the conversion of plantations via the spontaneous colonisation of hardwood species (i.e.…”