The history of the ecological component in the ideology of nationalists (and hereafter of national socialists) has begun in 1815 when the German nationalist Moritz Arndt has published his work «On protection and forest conservation», directed against uncontrollable and ruthless deforestation and exploitation of the soil, contradicting wholesome logic. In 1853 Wilhelm Riehl (Arndt's apprentice)  presented the work «The woods and fields». Quote from this work: «We must keep the woods not only to warm our houses in the winter but to allow people's life to pulse sincerely and joyfully; Germany remained German». In my opinion, this thought is extremely logical — protection of race certainly includes protection and preservation of habitat of race, especially in the nature where everything is interconnected.
The following stage of development of national-ecology is connected with Ernst Haeckel
(1834-1919) who has entered the word «ecology» in a row of scientific and political terms. He also immediately founded «the German Monist League». The ideology of the League has been presented in the principles of Lebensgesetze («Laws of life», the author is the biologist Raul Franke) according to which natural order defines social order. So, for example, interracial marriages were considered as «unnatural». Similarly Ludwig Voltman in the book «Political Anthropology» advanced the thesis about direct interrelation between purity of environment and racial purity: «The climate, quality, form and borders of a terrestrial surface, as well as ecological conditions of development, have to be taken into account on a discussion of historical factors».
«Mein Kampf» of national-ecologists has been published in 1913 in Meissner, on a meeting of the ecological national organization «Wandervogel» («Migratory birds»). There the book «Person and World» was presented: the German philosopher Ludwig Klages was its  author. In this program of work he designated the opposition of national-ecology to an urbanistic civilization as a plane of opposition of ideology and civilizations. Ludwig Klages, as well as hundreds of thousands of «Wandervogel ( migratiry  birds) » shortly after  became members of NSDAP. As a result the ecological doctrine of  «Blood and the Soil» became «one of basic elements of national socialism».