REPRODtTCTTON OF WESTERK YELLOW PINE. 



91 



disease has affected the tree must, of 

 course, be taken into consideration. 

 A badly diseased tree should not be 

 left even tliough seeding and protec- 

 tion purposes must be sacrificed on 

 small areas. On the other hand, a 

 tree which shows evidence of disease 

 but which will clearly remain thrifty 

 for 10, 20, or 30 years is better left as 

 a seed tree or for protection where 

 needed than no tree at all. 



9. Defects of mechanical nature. — 

 These include fire scars or cat faces, 

 broken tops, lightning cracks, forked 

 boles or tops, crooks, resin flow, etc. 

 In this district, resin-flow wounds or 

 " sores " a foot or more in length 

 usually indicate the tree to be on the 

 decline. Marking will, in so far as 

 conditions permit, aim to remove not 

 only diseased and insect infested trees 

 in accordance with the above stand- 

 ards, but likewise all badly defective 

 trees, yellow pines uniformly, black- 

 jacks and intermediate trees whose 

 growth is permanently retarded by 

 the defect, provided, in both instances, 

 other trees are available in the form 

 of seed trees or permanently estab- 

 lished reproduction. Therefore, defec- 

 tive trees will be marked for cutting 

 except when more valuable for seed 

 protection or future growth. A tree 

 which is not too badly defective but 

 is apparently thrifty is better left for 

 seed and protection than no tree at 

 all. The marking of such defective 

 trees which are not now merchantable 

 and which can not be counted on for 

 increased growth will be aimed at 

 where reproduction is established or 

 suitable seed trees are available, and 

 in future contracts will be fully 

 covered. 



10. Insect infestation. — All trees in- 

 fested with living pine beetles will be 

 marked for cutting, regardless of their 

 need for seed and protection. 



11. Windfall and lightning. — On 

 areas of high windfall or lightning 

 hazard, it may often be necessary to 

 leave more trees, especially if yellow 

 pines, than indicated in the above 

 standard. As a protection against 

 windfall, the leaving of trees in 

 groups, as far as possible, is advis- 

 able. This is particularly true of 

 yellow pine trees which must be left 

 because of the absence of blackjacks. 

 Yellow pine trees are more subject to 

 windfall than are blackjacks. Avoid 

 as far as possible the leaving of tall 

 trees or those containing more than 

 four logs. Avoid wherever possible the 

 opening up of trees which have pre- 

 viously been protected by others. 



With the possible exception of fork- 

 ing, which may be hereditary, me- 

 chanical defects of the character men- 

 tioned apparently do not seem to im- 

 pair the value of a tree for reproduc- 

 tion, unless the area of the crown is 

 reduced. Therefore, in the absence 

 of sound trees, defective trees may be 

 left for reproduction. Some studies 

 have shown higher germination for 

 trees with certain mechanical defects 

 than for sound ones ; but the evi- 

 dence is not sufficiently conclusive to 

 warrant leaving defective trees where 

 they are not needed. 



No comment. 



From the standpoint of seed pro- 

 duction and the effective utilization of 

 light and soil, the arrangement by 

 groups is undesirable. But it is now 

 generally accepted that if the majority 

 of the trees in an even-aged group are 

 cut, the remaining members will be 

 subject to windfall. For this reason 

 it is desirable to treat the group as a 

 single unit, either leaving the entire 

 group, except for light thinnings, or 

 cutting the entire group. In either 

 case, however,, it is often possible to 

 make exceptions of individual trees. 

 One-sided or leaning trees are liable 



