Stand structure after thinning in 1–2 m wide corridors in young dense stands

Kristina Ahnlund Ulvcrona, Dan Bergström, Urban Bergsten
2017 Silva Fennica  
Highlights • Boom corridor thinning (BCT) results in more stand structure heterogeneity than conventional thinning or pre-commercial thinning (PCT), maintaining both smaller-diameter trees and deciduous species. • Neither dominant height nor number of possible future crop trees is jeopardized, and boom corridor thinning results in higher values of stem volume and biomass. • The technique is flexible as various corridor types give similar stand structure results. Abstract Boom corridor thinning
more » ... corridor thinning (BCT) has been proposed as a cost-effective technique for biomass thinning (BT) in young dense stands. The objective of this study was to determine how various BCT operations affect stand structure following biomass thinning and to compare the results with conventional selective thinning methods. Two series of field experiments were established; BCT 1-series: Three sites in south of Sweden (9 and 11 m in mean and dominating tree height) with five treatments, including a control, conventional selective thinning and three BCT treatments (1 m and 2 m wide corridors and selective BCT). The second BCT series: Three regions in Sweden (in the north, centre and in the south), with two stand sites in each region with different tree heights (4/9 m and 5/10 m in mean/dominating tree height). Treatments were control, precommercial thinning (PCT), conventional selective thinning and BCT (high and low thinning). Following the first biomass thinning, BCT regimes and selective thinning methods resulted in similar stand structures based on the number of possible future crop trees (>80 mm in diameter at breast height). However, BCT maintained a higher diversity of tree sizes as well as more stems per hectare, including deciduous species, than the selective thinning approaches. The stands after BCT should have more vertical complexity, especially when compared to pre-commercial thinning. The structural heterogeneity resulting from BCT may also increase stand biodiversity and ecosystem service values.
doi:10.14214/sf.1563 fatcat:vzloyrvmqbdjrpwnhlukicf5qy