Regeneration of red and silver beech: How important is the size of harvested area?

Authors: Susan K. Wiser, Gordon Baker, Udo Benecke
Publication: New Zealand Journal of Forestry, Volume N.Z.J.For. 2007, Issue N.Z.J.For. 52(2) 2007, pp 31-35, Aug 2007
Publisher: New Zealand Institute of Forestry

---

Abstract: Successful regeneration is a critical part of sustainable management of indigenous forest. Although current legislation allows a range of cut sizes within a management plan, in practice, managers tend to gravitate to a narrow span of harvest areas and use a particular extraction method. Here, we analyse 8 years of data from experimental coupe and group-selection harvesting trials in mixed red-silver beech forest to compare and contrast the effect of harvest area on light availability, soil conditions and beech regeneration. Coupe and group selection subplots differed initially in that group selections tended to be on higher landform positions (more on ridges and spurs, less in gullies) and have higher potential solar radiation than coupes. After harvesting coupe subplots had higher maximum water fern frequency, soil Ca, soil pH, soil mineralisable N, mean litter depth, and exotic plant species occurrence than group-selection subplots. All of these variables appear to be directly related to the size of the harvested area. Coupes appear to provide the best conditions for regeneration of red beech, whereas group selection harvests provide the best conditions for silver beech. This follows expectations about how a shade-intolerant (red beech) versus a shade-tolerant (silver beech) tree species would be expected to respond to different sizes of canopy gap openings. Our results imply that, all else being equal, a range of sizes of harvested areas will promote a more mixed-species forest, whereas uniform sizes of harvested areas are likely to favour one species over the other.

---