. DEVELOPMENT OF BRUSH-DISPOSAL POLICY 701 



that seedlings will not start within lo years after the tree is felled. 

 After that the conditions for the growth of seedlings are undoubtedly 

 better than in the open. 



The effect of scattered brush varies greatly in different stages. 

 Within the first two or three years after the brush is scattered, it inter- 

 feres to some extent with seed reaching the ground and shades the 

 seedlings excessively. On the other hand, it protects against frost and 

 excessive evaporation. After the third year, the needles form a dense 

 mat on the ground, and in this stage they are most effective in prevent- 

 ing seed from reaching the mineral soil. After the needles drop, the 

 shade is comparatively light. 



The advocates of brush scattering have made much of the beneficial 

 effects resulting from the addition of organic matter to the soil. I have 

 recently come to the conclusion that this benefit has been greatly over- 

 estimated. I have observed on cuttings 15 or 20 years old that where 

 branches have fallen there usually remains more or less litter, but the 

 soil underneath shows no addition of organic matter. In our dry 

 atmosphere the litter instead of rotting tends to dry up and blow away. 

 Where there is a heavy accumulation of litter, as in the case of tree- 

 tops left intact, brush piles, and the ground under standing trees where 

 leaves have accumulated for centuries, an examination of the soil 

 usually shows a black or brownish color, indicating the presence of 

 humus. My conclusion from these observations is that where brush 

 is scattered lightly, so as to avoid excessive shading and excessive inter-' 

 ference with seeding, the effect to be expected from the addition of 

 organic matter to the soil is negligible. One or the greatest advantages 

 of scattered brush is that it tends to kill out grass and other competing 

 vegetation. In order to do this, however, it must be dense, so that when 

 it packs down it will form a mat two or three inches in thickness. I 

 believe that the best results from scattered brush can be obtained by 

 placing two or three branches together, so as to form a heavy cover, 

 but leaving frequent small openings between these piles. Seed can 

 germinate in these openings. The seedlings will receive considerable 

 protection from the surrounding brush. They will eventually send 

 their roots into the area covered by the brush, where they will find con- 

 siderably more moisture than in spots where there is no cover. 



I believe that after weighing the advantages and disadvantages of 

 scattered brush the net balance will be favorable. We have tried to 

 secure concrete evidence by observing areas where brush has been 

 scattered, but unfortunately after ten years, although there seems to be 

 a slight advantage in favor of the brush, results are not what I would 



