History of Forest Ecology 393 



Tournefort (45), in 1717, was perhaps the first to recognize 

 zonation when he compared the vegetation of all Europe to that 

 found on the slopes Mount Ararat. Raimond (46) studied and 

 described the zones of vegetation of the Pyrenees Mountains. 

 Humboldt and Bonpland (47) used the word "region" to desig- 

 nate the zones of mountains and the word "zone" to designate 

 the vegetative belts determined by latitude. Schouw (22) 

 followed this use of the terms zone and region, but diflferentiated 

 between zones of latitude and longitude. Grisebach (36) estab- 

 lished zones based upon the dominant trees. Koppen (48) and 

 Drude (49) established certain zones based upon temperature. 

 Many studies have been carried on to determine the zonal arrange- 

 ment of plants on small areas. Raunkiaer (50) noted zonal ar- 

 rangement in the dune valleys of Jutland as early as 1889. Magnin 

 (51) studied the zonation of the Jura lakes and MacMillan (52) 

 in our own country described zonation in the sphagnum moors of 

 Minnesota. These are merely some of the more important efforts. 

 It is interesting to note that during the last century alone not 

 less than 60 different proposals of geographic zones and regions 

 have been published. 



Modern Plant Ecology 



Plant ecology, as will be seen from what has been said, has 

 developed along at least four distinct lines, namely : plant distri- 

 bution, plant formations and associations, experimental ecology, 

 and the study of habitat factors. This large and diversified field 

 of inquiry has only within the last 20 years become more unified 

 and systematized. The whole was put into a huge melting-pot, 

 as it were, and a few guiding principles were crystallized out. The 

 science was more closely delimited and divided into natural 

 groups. These groups were defined and classified. Grisebach's 

 conception of a plant formation was amplified and extended by 

 dividing and redividing this unit of vegetation into its component 

 parts. As vegetation was analyzed more closely, the underlying 

 causes of the various vegetative units came into the lime-light. 

 This led to the dynamic ecology of the present day. 



Dr. Carl Schroter, the eminent Swiss ecologist, is often spoken 

 of as the father of modern ecology, principally because he brought 

 order out of a chaotic condition of affairs. Schroter divided the 

 whole field of ecological inquiry into two great divisions, namely : 



