CONIFEROUS FOREST TREES IN GREAT BRITAIN. 75 



acre. Its volume production is almost twice that of larch under 

 similar conditions. 



The timber of Norway spruce is light and fairly durable when 

 kept dry. It cannot compare with larch or Scots pine in 

 strength. Its principal uses are for constructional purposes 

 and for pit-wood. 



The principal silvicultural problem to be solved is how to 

 grow moderately clean timber. The dead branches persist 

 for a long time, and the timber grown in this country up 

 to the present is much more knotty than that grown in some 

 other parts of Europe. The trees to form the final crop 

 could be selected at 25-40 years and pruned up to 20 feet. 

 Close planting has been advocated and tried to remedy this 

 defect. Spruce may be planted closer than the species already 

 discussed because its rate of growth in early life is slow even 

 under the best conditions. Hence, in order to close the canopy 

 in a given time, closer planting is necessary. This should not 

 be carried too far, however, especially on the poorer soils. 

 Under such conditions, the roots have to go farther for the food. 

 More root room is necessary on the poorer soils than on the 

 better soils, hence the planting should be wider. Probably even 

 for spruce the minimum planting distance should be 4 feet, and 

 in some cases it should be wider. The side branches are 

 thinner when the plantation is kept dense, but in determining 

 the correct density other silvicultural factors must be considered 

 also. Spruce being a shade-bearer, a heavier stock may be 

 carried throughout the rotation. This heavier stock and the 

 increment which it produces is one of the principal advantages 

 of the species. To obtain the maximum increment and size of 

 individual stems, moderate to heavy thinnings are, however, 

 necessary. The best degree of thinning for the various 

 conditions is a matter for further investigation. 



Up to recent years spruce was not a favourite tree in this 

 country. It has now, however, many advocates. As can be 

 seen, the author considers that its requirements are not so 

 exacting as was believed. It nevertheless has requirements, 

 and care must be taken to see that it is not planted in places 

 which do not meet these. Up to the present it has been 

 found very difficult to establish on ground whose principal 

 soil covering is heather (Calluna). Spruce is assured of an 

 important place in the forestry development of this country. 



