It is interesting to note that at that time the Catalpa played a role, at least on paper, as it does in our own day, being recommended as the only means of staving off the timber famine. A renewed _betulomania_ spread widely over the country. In North Germany especially, great efforts were made to replant the denuded areas and to change the coppice areas, fit only for firewood, to coniferous species, pine, etc., by which eventually a great change in the forest type from the original mixed forest to the pure forest was effected. 3. _Personnel._ The great change which led to improved conditions, during the first half of the century, was pre-eminently due to the knowledge and intelligence of a group of men, six in number, competent foresters, who combined the high grade education of the Cameralists with the practitioners’ knowledge: Hartig, Cotta, Hundeshagen, Koenig, Pfeil and Heyer. These men built, to be sure, on the shoulders of their precursors of the century in which they were born, but, being placed in authoritative positions, found better opportunities for putting their teachings into practice. The first two mentioned were older than the rest, and are usually described as the “fathers of modern forestry.” Born about a year apart, both educated at universities, they excelled in both scientific and practical directions. _Georg Ludwig Hartig_ (1764-1837), studied at the University of Giessen and, after having served in various functions in various parts of Southern Germany, became, in 1811, head of the Prussian forest administration. He was equally eminent as a practical man and organizer, as a writer, and as a teacher. In literary direction his work lay not so much in developing new ideas as in formulating clearly the known ones, as evidenced in his celebrated “General Rules” in silviculture. Not less than thirty separate publications attest his assiduity. Among them stands pre-eminent “_Anweisung zur Holzzucht für Foerster_” (1791; 8th edition, 1818). As a teacher he began his work by establishing a masterschool (1789-1791) at Hungen, transferred to Stuttgart in 1807; and afterwards, as head of the Prussian forest administration, he lectured at the University of Berlin, continuing his lectures there, even after the forestry school at Eberswalde had been established, until his death.