ALGARROBO (Carob Tree), _Prosopis alba_, Grisb.—From 15 to 20 metres in height by 1 metre in diameter, with timber much used in carpentry, and bark possessing a large percentage of tannin. A good kind for afforestation in regions 1, 2 and 4; to be sown as stock trees in furrows or small holes. ÑANDUBAY, _Prosopis algarrobilo_, Grisb.—About 10 metres in height, with hard timber, generally used for large stakes and posts. Grows well throughout the northern and even in the third region. To be sown as an auxiliary in mixed woods. IRIRARÚ, VIRARÚ, PALO DE LANZA (Lancewood), _Ruprechtia excelsa_, Grisb.—10 to 15 metres in height by 0·75 metre in diameter; giving excellent timber for various household purposes. To be sown as an auxiliary in woods of the northern regions, predominating among timber for cutting. LAPACHO, _Tabebuia Avellanedæ_, LORENTZ, _Tabebuia flavescens_, Benth.—This beautiful tree is covered with blossoms in spring time, the former with pinky mauve and the latter with yellow blossoms. In the northern forests it grows to a height of 25 metres, its wood is very fine-grained and very much prized for all sorts of fine carpentry. Two excellent kinds for stock in tall mixed woods, 1st and 2nd regions. To be sown in rows, in furrows or small holes. COCO (Cocoanut Tree), _Zanthoxylum Coco_, Gill.—From 10 to 12 metres in height by 0·75 metre in diameter. The wood is very pretty and fine, valued for elegant furniture. To be sown in rows, furrows or small holes as an auxiliary in mixed woods and plantations in the 1st and 2nd regions. URUNDAY, _Astronium juglandifolium_, Grisb.—A splendid tree from 25 to 30 metres in height by 1·50 metres in diameter, common in the Chaco. Its timber is very hard and richly coloured, it is used for furniture, ship-building, etc. One of the best kinds for stock and reafforestation in the first region. Multiplies naturally from seed if care be taken to leave a few trees standing at suitable distances for producing seeds, which scatter easily. In the warm valleys of the 4th region, as well as in the 2nd, to be sown in furrows with other auxiliary species for afforestation. ALDER TREE, _Alnus ferruginea_, Kth.—From the Northern Andean region, where it grows to a height of 15 metres by 0·75 metre in diameter. Gives white, very easily worked, damp-resisting timber, used for joinery work. A good auxiliary kind for afforestation in 1st, 2nd, 4th and 7th regions. To be sown in rows, in furrows or in plots with other species, one being the stock tree.