tailieunhanh - Báo cáo nghiên cứu nông nghiệp " Seed collection procedures for Acacia Seed Orchards and Seed Production Areas "

The collection of seed from planted trees in a Seed Orchard (SO) Seed Production Area (SPA) generally requires access to seed-bearing branches at heights. High lift machinery or climbing methods can be used to obtain required working heights. High lift machinery is the more efficient option, reducing the risks associated with climbing and chainsaw operation. In cases where high lift machinery is not available or too expensive, climbing is a viable option. Working at heights involves considerable risks, but with proper equipment, training and management practices those risks can be minimised | Seed collection procedures for Acacia Seed Orchards and Seed Production Areas John Larmour ATSC CSIRO FFP 1. Introduction The collection of seed from planted trees in a Seed Orchard SO Seed Production Area SPA generally requires access to seed-bearing branches at heights. High lift machinery or climbing methods can be used to obtain required working heights. High lift machinery is the more efficient option reducing the risks associated with climbing and chainsaw operation. In cases where high lift machinery is not available or too expensive climbing is a viable option. Working at heights involves considerable risks but with proper equipment training and management practices those risks can be minimised. Climber with safety harness and rope straps around Acacia mangium tree bole. Ladder is secured to bole. 1 2. Management of Acacia seed orchards Management of Acacia seed orchards varies depending on the species site and requirements of future seed collections. Management strategies should take into consideration the health of the trees practical and efficient methods of removal of large quantities of seed-bearing material and the long-term impact of repeated seed collections. The size and shape of the trees on which seed collections are undertaken varies depending on species age and previous management strategies. Stocking rates determined by initial planting density and subsequent cycles of selective thinning influence tree form. Trees grown at wide spacing fewer than 200 trees per hectare develop wider crowns and heavier larger lateral branches. Tropical acacia species can be managed by pollarding removing the tops to promote lateral seed-bearing branches at a lower height 6-10 metres than if the tree was left with a dominant leader 20 metres on a good site . This height reduction makes a big contribution to improving safety by reducing the dangers of falling. Management strategies for acacia seed production areas have to consider the relative short-lived nature .