Developments in Yield Control and Inventory in British Forestry

Forecasting timber production many years in advance has becomea problem of considerable importance in this country becauseof the need to co-ordinate the rapid increase in productionwith the establishment of new timber-using industries. Thispaper describes a change in emphasis in state forest WorkingPlan Inventory methods employed in the predominantly young,coniferous forests of Great Britain and is a development ofthe methods described in a previous paper (‘Problems ofYield Control and Inventory in British Forestry’—D.R. Johnston, 1960, Forestry, 33, 19–36). Total enumerationof the growing stock is no longer the main objective of forestinventory and the new approach is directed towards (a) assessmentof the productive potential of each subcompartment and (b) theintensive enumeration of sample or ‘index’ subcompartmentsinitially and at each re-enumeration as a check on growth predictionsand yield control.     

THE INFLUENCE OF FERTILIZER ON THE WINTER SURVIVAL OF INTERMEDIATE WHEATGRASS FOLLOWING A LONG PERIOD OF DROUGHT

In Saskatchewan, intermediate wheatgrass ( Agropyron intermedium Host. Beauv.) suffered severe winter injury during the 1961–2 winter season, which followed a series of drought years, the most severe being 1961. In two tests, designed to study fertilizer effects, the extent of severe winter injury increased with the rate of application. The killing ranged from 4% where no fertilizer was applied to 90% where 66 lb of N per acre were applied. Slightly more winter-killing occurred after applications of ammonium phosphate/sulphate (16-20-0) fertilizer than after ammonium nitrate (33·5-0-0).
The grass growing in rows 36 in. apart killed out to a greater extent than that growing in rows 18 in apart Less winter injury occurred after spring applications of fertilizer than after application in the fall.     

THE EFFECT OF HISTAMINE ON SILAGE DRY-MATTER INTAKE

The oral introduction of 0·5 g histamine as the diphosphate into the rumen of sheep produced no effect on the physiological condition of the animals. The feeding of histamine, as the dihydrochloride, in levels up to 1 g/day to sheep on silage diets did not affect the dry-matter intake.