12 BULLETIN 1105, U. S. DEPARTMENT OF AGRICULTURE. 



Table 5. — Seed production in relation to character of tree. 



Character of tree. 



Pounds 

 of seeds 

 per tree. 



Percentage 



germinat- 

 ing in 35 

 days. 



Number 

 of seeds 



per 

 pound, 



1913. 



Repro- 

 ductive 

 value,! 

 1913. 



Aver- 

 age 



diam- 

 eter 



breast- 

 high, 

 1913. 



Number 

 of trees 

 used as 

 basis. 





1909 



1913 



1909 



1913 



1909 



1913 



Yellow pine: 2 



Normal trees . . 



2.16 



1.07 

 .44 

 1.19 

 1.37 

 1.28 



.79 



.61 



1.61 



.18 



.39 

 1.90 



04 



79 

 79 

 67 

 53 



83 

 82 

 84 

 82 

 83 



88 

 79 

 82 

 83 



82 

 81 



14,300 

 15, 200 

 14,300 

 14, 600 

 13,100 



14,600 

 14, 700 

 14, 700 

 13,500 



16,400 

 14,600 



12,700 

 5,500 

 14,300 

 16, 400 

 13,900 



10,100 

 7,100 



19,400 

 2,000 



5,200 

 22, 500 



Inches. 

 24.6 

 16.9 

 21.9 

 27.9 

 33.0 



25.3 

 23.9 

 24.7 

 13.9 



18.9 

 27.0 

 19.1 

 20.1 

 14.7 



36 



7 

 15 



'S 



"'26' 



3 



49 



D. b. h. below 18 in 



4 



D. b. h. 18-24 in.. . . 





19 



D. b. h. 25-30 in 





19 



D. b. h. over 30 in. 





7 



Abnormal trees: 



Spike-top 



1.08 

 2.52 

 2.62 



.48 



4 



Basal burn 



5 



Heart rot 



12 



Suppressed 



4 



Mistletoe — 



Heavy... . 



8 



Light 





8 



Blackjack, above 12 in 





9 



Normal 



1.20 

 .50 



.93 



.58 



78 

 51 



81 



78 



14,500 

 14, 700 



io, 900 

 6,700 



6 



Mistletoe 



3 







1 Reproductive value is the number of germinable seeds per tree. 



2 "YeUow pineV are mature trees usually over 200 years old; "blackjack" immature, usually below 

 200 years. 



The data secured from the 1909 collection were analyzed in For- 

 est Service Circular No. 196 (16). Although the main conclusions 

 have been confirmed in a general way by the 1913 data, it may be 

 seen from the table that the relation between normal and abnormal 

 trees of various classes is more or less inconsistent. This is attribut- 

 able in some instances to insufficient data. In other intances, as in 

 the case of basal burn and heart rot, it is doubtful whether the 

 physiological functions are materially affected, excepting in extreme 

 cases. Since diseased and defective trees are, as a rule, removed 

 from the stand for silvicultural reasons, a knowledge of their re- 

 productive capacity is of only secondary importance in dealing with 

 cut-over stands. It is sufficient here to state that diseased, defective, 

 and over-mature trees do produce seed somewhat in proportion to 

 their active crown area, and that the seed is not of appreciably infe- 

 rior viability. The main objection to leaving such trees is that they 

 deteriorate rapidly and are carriers of disease which may be trans- 

 mitted to the future stand. Seed trees infected with mistletoe are 

 especially objectionable, because the mistletoe spreads to young 

 trees. Light or moderate infection does not seem to interfere seri- 

 ously with seed production, but heavy infection greatly reduces the 

 yield and probably the viability of seed. The most important prin- 

 ciple to be borne in mind is that, other things being equal, the 

 capacity of a tree to produce seed is determined by effective leaf sur- 

 face, and that anything which tends to reduce the size of the crown 

 or its efficiency as a food laboratory ultimately reduces the quantity 

 and possibly also the quality of seed. 



