Opinionated and one-sided, like many so-called practical men, he came into polemic controversies with other practitioners, not less opinionated, among them _J. G. Beckmann_, who worked in another part of Saxony, where, having to deal with coniferous woods, he had gathered different experiences from those of Doebel. Although he was himself poorly educated, especially in natural sciences, he complained of the ignorance of the foresters, and in his book (_Anweisung zu einer pfleglichen Forstwirthschaft_, 1759), used for the first time the word _Forstwissenschaft_ (forest science), and insisted upon the necessity of studying nature.
He may be credited with having really advanced forest organization by devising the first good volume division method, and silviculture by advocating the method of clearing followed by sowing.
The first practical forester with a university education was _J. J. Büchting_, who worked in the Harz mountains. His main interest lay in the direction of survey, division and orderly utilization. He did not, however, make any striking advance, except that he gave equal standing to both planting and sowing.
The two most eminent practitioners of the period, however, active during the middle of the century, were _Johann Georg von Langen_ and his pupil, _Hans Dietrich von Zanthier_, both of noble family, and better educated than most of their contemporaries, and both engaged in the organization and management of Harz mountain forests, namely, those of the Duke of Brunswick and of the Count of Stolberg-Wernigerode.
The former, without occupying himself directly with literary work, laid down in his expert reports and in his working plans many instructions which form the basis for orderly management and silviculture far ahead of the times. Zanthier, writing considerably (especially _Kurzer systematischer Grundriss der praktischen Forstwissenschaft_, 1764), is also notable as the founder of the first forestry school (at Wernigerode), 1763.
Another of this class of better educated practitioners, and co-worker with the former two, was _von Lassberg_, who in 1764-1777 organized the Saxon forests.
An interesting incident in the life of the last three men is their journey to Denmark and Norway, whither they were called to organize the management of the forests connected with the mines.