This part of ISO 11681 specifies safety requirements and their verification for the design and construction of portable combustion-engine, hand-held chain-saws for tree service, having a maximum mass, without guide bar or saw chain and with tanks empty, equal to 4,3 kg, and designed for use by a trained operator for pruning and dismantling standing tree crowns. It gives methods for the elimination or reduction of hazards arising from the use of the chain-saws. In