Influence of cambial age on the bark structure of Douglas-fir

摘要: Douglas-fir (Pseudotsuga menziesii) is a valuable conifer timber species. It has thick bark with high proportion of cork in the rhytidome that allows considering its recovery. This study focuses on characterization features and their variation cambial age along stem using samples 20 trees from two sites Portugal at harvest for sawmilling industry. The morphology anatomical were examined including detailed analysis arrangement tissues, cell biometry, tissue phloem, development rhytidome. Bark structure varied within tree various height levels, differences concerned mostly periderm development, disarray non-conducting phloem. A relationship between dimension, tissues phloem was observed; effect position statistically significant sieve length, fiber–sclereid length wall thickness decrease base to top. increased age: At (45–50 years age), includes about 3 cm corresponding 84% bark, 5–8 periderms, containing nearly 50% cork. cells thin-walled oriented radial rows, occurrence thick-walled lignified associated increments phellem layer. In youngest periderm, empty lumens thin suberized walls started 25–30 years age. results show 45–50 years logs up 5 m may be suitable exploitation.