PERIODICAL LITERATURE 87 



The general conclusions which may be drawn from these figures 

 appear to be that in the average season timber increment commences 

 about the middle of May and attains its maximum in June, during 

 which month one-third of the whole increment is laid on. There is a 

 gradual falling ofif in the growth during July and August, when in 

 many cases increase in girth ceases. In certain trees, especially on 

 better soils, a small growth is made in September. It has been ob- 

 served that a cold, backward season, with an absence of sun, may post- 

 pone any timber increment until June, but rainfall in the early part of 

 the season is not so important, no doubt because there is rarely any 

 lack of soil moisture at that period. Prolonged dry weather in the 

 latter half of June or in July has, however, a very marked effect on 

 both spruce and Japanese larch, although when sufficient rain does fall 

 the loss of growth is usually made up. 



Observations i)i Connection n'ith Annual Increment of Growing Crops of Tim- 

 ber. Transactions of Roval Scottish Arboricultural Society, Julv, 1918, pp. 

 164-168. 



The city forest of Winterthur is one of the 

 Sii'iss best managed and most productive in Switzer- 



Forcst land. It contains around 2,800 acres, mostly 



Production conifers, and in 1917, without exceeding the sus- 



tained yield with a cut of 75 cubic feet, the net 

 return was over $50,000, or over $17 per acre. To be sure, the wood 

 prices were high, 22.6 cents per cubic foot, an increase of 46 per cent 

 over 1916. The workwood per cent was 70, leaving 30 per cent for 

 fuelwood. A nursery of 160 acres furnishes plant material, part of 

 which is for sale. 



The cantonal forest of Soleure, also only about 3,000 acres, produced, 

 with a sustained yield of only 37 cubic feet, a little over $8 per acre. 



In the communal forests of St. Gallen the cut was 81 cubic feet, with 

 a gross return of a little over $13; net results are not given, but the 

 interesting fact is stated that of the principal cut, 7 per cent w^as from 

 clearing system, 51 per cent from successive fellings, 40 per cent from 

 selection cuttings. 



For the canton Bern it is stated that while in the public forests the 

 cut has remained nearly normal, in private forests it has increased to 

 treble what it was in 1913. The net price has exactly doubled over 

 that of 1915, and is stated for 1917 at 16 cents per cubic foot. 



In the canton Vaud the cantonal forests produce at the rate of 61 

 cubic feet per acre, the communal forests at 57 cubic feet, but the pri- 



