tailieunhanh - Báo cáo lâm nghiệp: "Picea glauca dynamics and spatial pattern of seedlings regeneration along a chronosequence in the mixedwood section of the boreal forest"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí lâm nghiệp đề tài: Picea glauca dynamics and spatial pattern of seedlings regeneration along a chronosequence in the mixedwood section of the boreal forest. | Ann. For. Sci. 61 2004 789-794 INRA EDP Sciences 2005 DOI forest 2004079 789 Original article Picea glauca dynamics and spatial pattern of seedlings regeneration along a chronosequence in the mixedwood section of the boreal forest Tala AWADAa Geoffrey M. HENEBRYb Robert E. REDMANNc Hari SULISTIYOWATIc a School of Natural Resources University of Nebraska-Lincoln 12 D Plant Industry Lincoln NE 68583-0814 USA b Center for Advanced Land Management Information Technologies CALMIT School of Natural Resources University of Nebraska-Lincoln 113 Nebraska Hall Lincoln NE 68588-0517 USA c Department of Plant Sciences University of Saskatchewan Saskatoon SK S7N 5A8 Canada Received 9 May 2003 accepted 6 February 2004 Abstract - We studied Picea glauca dynamics in the boreal forest of Saskatchewan Canada using 35 stands ranging from 1 to 200 y after fire. We determined the spatial pattern and the importance of seedbed conditions to the recruitment of P. glauca. Basal area increased along the chronosequence peaking at 110 y after fire m1 2 ha-1 . The ratio of softwood to hardwood increased from 16 y to 172 y . Picea glauca tree density increased with stand age highest densities were observed in a 172 y stand 1413 stems ha-1 . Picea glauca dominated the canopy between 93 and 172 y after fire. Picea glauca snags appeared about 66 y after fire and remained relatively low in density until 160 y. Saplings were present at varying densities along the chronosequence. Seedlings established immediately after fire and exhibited bimodality with lowest densities observed between 110 and 125 y. Analysis with Ripley s K showed that seedlings were mainly distributed at random in young stands but were clumped at a distances 12 m in old stands. In young stands the majority of seedlings regenerated on the organic layer LFH 73 while recruitment was almost exclusively on logs in old stands 94 . Picea glauca regeneration depended on propagule availability and seedbed .