形成层是位于韧皮部和木质部之间的一层狭窄且具有(  )的细胞层。 2022-01-07 The first step in harvesting a timber is ______. 2022-01-07 Diameter at breast height is usually measured at ______ above "ground level". 2022-01-07 质量认证有两种表示方法，即产品质量认证证书和产品质量(  )。 2022-01-07 心材腐朽是(  )受木腐菌侵害所形成的心材部分的腐朽。 2022-01-07 生产工艺是形成(  )的关键，对其具有决定性作用。 2022-01-07 国际电工委员会标准，2002年发布的第6010号。 2022-01-07 A logger planned to work from 6 AM to 4 PM with 30 minutes for lunch, his skidder would have 9.5 SMH per day. If the skidder spent 30 minutes waiting for trees to be felled, 20 minutes replacing a hydraulic fitting, and 10 minutes moving to another landing, total payload is 200m³, please calculate the productivity per PMH and MA, UT. 2022-01-07 The major forest products include ______. 2022-01-07 DB23/796—2000 2022-01-07