1 6 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



3. On Planting Distances for Conifers. 



By Mark L. Anderson, M.C, B.Sc. 



To determine the most suitable spacing at wliich to plant 

 young trees in the formation of woods, has been a matter of 

 some difficulty to foresters, not only in this but in other countries. 

 At the moment it is a very vexed question, and, if the policy 

 of narrow spacing has its advocates, the policy of wider spacing 

 has no laclc of staunch adherents. It is the purpose of this 

 article to endeavour to show what are the effects of narrow 

 and wide planting intervals on the development of woods, and 

 to point out the advantages and disadvantages of both methods. 

 Much of the information has been culled from continental 

 literature dealing with the subject. The writer, however, claims 

 to possess a fair knowledge of young woods and plantations of 

 all the commoner species in many parts of Scotland. 



The effects of different planting intervals can be dealt with 

 from two aspects, namely, the silvicultural side and the financial 

 or business side. It is proposed to deal with the silvicultural 

 side first, since it is the more important and carries more weight 

 with the forester. 



The Silvicultural Aspect. 



The life-history of a wood may be divided into four periods, 

 namely, (i) The period of formation, from the planting or sowing 

 of the wood up to the closing of the canopy ; (2) the period of 

 competition, from the closing of the canopy up to the time when 

 only those trees which are to form the final crop remain ; 

 {3) the period of diameter-growth and reproduction; (4) The 

 period of decay. In well-managed woods, the last period 

 should never occur, since the end of the rotation will usually 

 fall due in the middle of the third period. In some cases when 

 trees are grown on short rotations for pit-wood, even the third 

 period may not be reached. 



So far, there are few, if any, advocates for a planting distance 

 of 10 feet by 10 feet or over. The main controversy rages 

 round the question of whether planting distances of 3 feet 

 square, or thereby, are better than distances of 8 feet square, 

 or thereby. In this article, distances of 3 feet square up to 

 5^ feet square are termed " close," while those from 6 feet 

 square up to 8 feet square are referred to as "open." 



