154 Transactions. 



Art. XVIII. — Notes from the Ganterhury College Mountain Biological 



Station. 



No. 3. — Some Economic Considerations concerning Montane Tussock 



Gras-sland. 



By A. H. Cockayne, Biologist, Department of Agriculture. 



[^Read before the Philosophical Institute of Canterbury, 1st December, 1915.] 



1. General. 



Montane low tussock grassland is not really sharply defined from low- 

 land low tussock grassland, both being very similar associations of the 

 same climatic formation. Tlie term should be applied only to that 

 tussock association in which Festuca 7iovae-zealandiae (Hack.) Cockayne 

 is the leading physiognomic plant, while lowland tussock grassland 

 should be restricted to that where the characteristic tussock growth-form 

 is represented by Poa caesjjitosa Hook. f. As implied by the name, 

 lowland tussock grassland is normally developed on land of low eleva- 

 tion, and rarely ascends higher than 1,000 ft. Poa caespitosa, however, 

 is not uncommon at higher elevations, but is then mainly confined to 

 moist places along the sides of streams and on the outskirts of forest, and 

 rarely becomes the dominant element of the open grassland. Between 

 true lowland tussock and true montane tussock many intermediate stages 

 can be found, where both Festuca novae-zealandiae and Poa caespitosa 

 are in more or less equal quantity. 



Much of the vegetation in the vicinity of the Cass JVIountain Bio- 

 logical Station is tj'^pical montane low tussock grassland, and, in fact, 

 it is the main climax association, apart from mountain southern -beech 

 forest, of all the area up to an altitude of over 3,000 ft. This is not 

 to say that many other associations are not present; but they nearly 

 all are stages in the ultimate production of montane grassland which 

 appears to be. under natural conditions, the final vegetation of the 

 land-surface, "except in sheltered situations, where true forest may be 

 developed. The presence of this uniform climatic formation, charac- 

 terized by tlie complete dominance, so far as general appearance is 

 concerned, of the even-sized and almost evenly spaced tussocks of Festuca 

 novae-zealandiae, is the special vegetation feature of the valleys and 

 slopes of the mountain-ranges east of the dividing range of the South 

 Island. 



2. Area and Distribution. 



. Montane tussock grassland is especially characteristic of the South 

 Island,* and comprises an area of over 6,000,000 acres, or, roughly, one- 



* In the North Island there is a considerable area of the formation here beirg dealt 

 with situated on the Volcanic Platesn southwards of Mount Ruapehn with Festuca 

 novae-zealandiae or a closely related variety or fpecies dominant. The Waimarino 

 Plain, on the contrary, on the west of the volcanoes, although at about the same altitude 

 (3,000 ft., more or less), has Danthonia Baoulii Hook f. as its dominant tussock. 



