CONTENTS 



Page 



Department Bulletin No. 1293. — Tillage and Rotation Experi- 

 ments at Dickinson, Hettinger, and Williston, N. Dak. — Contd. 



Soils 4 



Plan of the experiments 5 



-Results of the experiments 5 



Average yields 5 



Results with fall plowing and spring plowing compared 7 



Results on fallow and following small grains compared 9 



Results on disked and on plowed corn ground compared 11 



Results on fallow compared with those on disked corn ground __ 11 



Results on fallow compared with those on disked potato ground. _ 13 

 Results on manured fallow compared with those on unmanured 



fallow 13 



Results with wheat on disked stubble 14 



Results with green manures 14 



Results with sod crops 16 



Results with continuous cropping 19 



Summary 21 



Department Bulletin No. 1294.— The R6le op Fire in the Cali- 

 fornia Pine Forests: 



Introduction . 1 



Fire history of the California pine region 3 



Data from fire scars 3 



Recurrence of fire years 4 



Causes of earliest fires 5 



Fires in the virgin forest 6 



Injury from fire scars 6 



Direct heat killing 11 



Crown injuries and rate of growth 15 



Indirect physical damage to mature timber 18 



Fire damage to young growth 24 



The process of attrition 29 



Fire in second-growth stands 31 



The crown-fire hazard 31 



Annihilation of stands 33 



Effect of repeated surface fires 34 



Other forms of fire damage 36 



Occasional benefits 36 



Fire damage on cut-over areas 36 



Effects of slash fires 37 



Effect on reproducing areas 38 



Fire in brush fields 39 



Site deterioration 39 



Reclaiming the brush fields 41 



Damage to watershed 44 



Light burning 45 



Technique 45 



History of growth and practice 46 



Results of light burning 47 



Summary of light-burning observations 59 



Possible beneficial uses of fire 61 



Use in slash disposal 62 



Use in other protective measures 65 



Use in silvicultural practice 68 



Use as an aid in grazing 70 



The relation of damage to forest management 71 



Effects on logging costs 72 



Effect on silvicultural practice 73 



Theory of fire protection as controlled by fire damage 74 



Summary 78 



Literature cited 80 



