| Abstrakt: |
In January 1998, an ice storm caused extensive and severe crown damage to the rare Pinus banksiana–P. rigida barrens in northeastern New York. These barrens contain some of the southernmost populations of P. banksiana and northernmost populations of P. rigida in the eastern US. Because P. banksiana showed particularly severe damage compared to P. rigida, and P. banksiana regeneration is absent or sparse in these stands, there is concern that P. banksiana importance may be dramatically reduced in severely damaged stands. In an attempt to reduce the risk of wildfire and to regenerate P. banksiana in such stands, restoration cuttings were completed in 1998 and 1999. Restoration cutting consisted of whole-tree harvesting (i.e. harvest of boles and attached branches) of nearly all standing trees, while branches and attached cones broken during the ice storm were left on-site as a seed source. In restoration cuttings, there were 23,400–39,800 P. banksiana seedlings/ha 2 years after harvesting, while few or no P. banksiana seedlings were observed in uncut damaged stands. P. banksiana seedling densities were several times as high in plots with evidence of soil scarification than in unscarified plots (54,000–63,600 and 12,100–30,300 P. banksiana seedlings/ha, respectively). Regeneration was positively related to cone density and negatively related to shrub and herbaceous species percent cover (e.g. R=0.30 and −0.55, respectively, for the 1999 cut), indicating the importance of even dispersal of cone-bearing slash and the reduction of competing vegetation. Restoration cutting can be used to regenerate P. banksiana in stands severely damaged by ice storms or other canopy disturbances (e.g. blowdown) if soils are adequately scarified and harvesting is conducted within a few years after canopy damage. [Copyright &y& Elsevier] |
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