204 TRAXSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



the flames to reach a height which would be out of the question in 

 the case of small fires. The area of the protection lines, therefore, 

 must not exceed a certain size, but must be divided by a ditch or 

 path from the rest of the wood, so as to restrict the surface fires 

 to dimensions which render crown fires impossible. How broad 

 a protective strip should be has not been definitely determined. 

 According to Dr Kienitz's observations, the correct breadth lies 

 between 40 and 50 feet, provided that this area is stocked with 

 Scots fir of about 20 to 50 feet in height, without large gaps, and 

 that the branches of the trees are pruned up as much as possible. 

 It has been noticed that bare lines in the Chorin forest have 

 been naturally seeded with Scots fir in many places, and that 

 these natural groups prove eS"ective spark interceptors, while they 

 are not injured by surface fires when pruned up and thinned out 

 to the proper extent. 



Dr Kienitz lays down the following rules for the management 

 of fire lines in Scots fir woods; he considers that they are based 

 on more economical principles than those hitherto followed. 

 When a new line is laid through a forest, it is desirable that 

 the Railway Department should purchase all land adjoining the 

 line which is required for storing material, the erection of tele- 

 graph lines, etc., and that also which must be kept clear of wood 

 for the proper working of the signals. The Department should 

 then maintain clear tracks of a yard in breadth along the boundary 

 of this land, so that fires breaking out on it may not extend 

 beyond it. Parallel to these tracks, and from 40 to 50 feet inside 

 the standing wood, the ground should be intersected by cross 

 tracks kept clear of all surface growth ; these would pre- 

 vent fires breaking out between them from spreading farther. 

 The trees standing on the area so intersected should be pruned 

 up at least 5 feet high by the Forest Department, but at the cost 

 of the Railway Administration, and all dead branches should be 

 taken ofi" annually. The wood should be thinned out to a distance 

 of 3 feet from tree to tree, and care taken that all blanks 

 are filled up. The surface of the ground should be cleared of all 

 inflammable material, such as dry grass, heath, etc.; but the light 

 covering of very poor soils might be left for the benefit of the 

 crop. In plantations under eight years of age, the ground 

 between the trees should be broken up until they have reached 

 a height of 8 feet, when they can be pruned up as described 

 above. In case sparks are found to ily over and through this 



