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Needle retention and needle loss of Scots pine in recent decades at Thetford and Alice Holt, England

 

作者: Risto E. Jalkanen,   Tarmo O. Aalto,   John L. Innes,   Timo T. Kurkela,   Ian K. Townsend,  

 

期刊: Canadian Journal of Forest Research  (NRC Available online 1994)
卷期: Volume 24, issue 4  

页码: 863-867

 

ISSN:0045-5067

 

年代: 1994

 

DOI:10.1139/x94-113

 

出版商: NRC Research Press

 

数据来源: NRC

 

摘要:

Fourteen Scots pines (PinussylvestrisL.) were felled in Thetford and Alice Holt forests, southern England, for needle retention studies. In the field, the main stem of each tree was divided into annual sections, with each section being reduced to 30 cm long bolts or less, omitting branch whorls and using the internodal part of each annual shoot. The bolts were then planed one annual ring at a time to reveal the location of needle traces. In the summers of 1950–1990, the average needle retention was 2.6. Average needle retention varied annually from 1.5 to 3.3. There was a slight reduction in needle retention following high values at the end of the 1960s, and this accelerated during the 1980s. Needle retention history was similar at both Thetford and Alice Holt. The amount of annual needle loss varied between 0.3 and 1.6 needle sets, and the 40-year average of 1.02 sets indicated a long-term reduction in the number of needle sets during the lifetime of the trees.

 

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