Abstract : Tree-based image representations are popular tools for many applications in mathematical morphology and image processing. Classically , one computes an attribute on each node of a tree and decides whether to preserve or remove some nodes upon the attribute function. This attribute function plays a key role for the good performance of tree-based applications. In this paper, we propose several algorithms to compute efficiently some attribute information. The first one is incremen-tal computation of information on region, contour, and context. Then we show how to compute efficiently extremal information along the contour (e.g., minimal gradient's magnitude along the contour). Lastly, we depict computation of extinction-based saliency map using tree-based image representations. The computation complexity and the memory cost of these algorithms are analyzed. To the best of our knowledge, except information on region, none of the other algorithms is presented explicitly in any state-of-the-art paper.