42 BULLETIN 299, IT. S. DEPARTMENT OF AGRICULTURE. 



old stand it may form but a very small proportion (PL XIV, fig. 1), 

 perhaps only three or four seed trees per acre. 



The fact that white and green ash have male and female flowers 

 borne on separate trees will not usually interfere with ash reproduc- 

 tion cuttings, as such cuttings will be made after it is apparent that 

 there is going to be a good seed year, and the tree which will have the 

 most seed can be picked out and reserved. In preliminary reproduc- 

 tion cuttings (to induce seed production) it should be remembered, 

 however, that one large-crowned male tree per acre will pollinate 

 more than enough flowers of female trees on that acre, and the remain- 

 ing males can be removed if desired. Determination of sex can be 

 made by marking trees which bear seed (female trees) in advance of 

 such cuttings. In mixed stands with a small percentage of ash and 

 where the sexes have not been determined, it will be best to leave all 

 large-crowned ash trees. 



METHODS OF CUTTING. 



The methods of cutting to secure natural reproduction of ash may 

 be grouped under two general systems ; the shelterwood system and 

 the clean-cutting system, the former being adapted to all sites on 

 which ash grows, the latter to a limited range of sites. The best 

 method to use in any particular case depends on a number of factors : 

 The species to be reproduced; the site, especially soil moisture and 

 soil covering; age and density of the stand, including the amount 

 and character of the undergrowth ; and proportion of ash in the mature 

 stand. 



SHELTERWOOD SYSTEM. 



The shelterwood system consists in the more or less gradual removal 

 of the mature stand, allowing reproduction to get well started under 

 the shelter of the mature stand before removing it entirely. This 

 system is especially suitable to upland white ash, as it preserves soil 

 moisture, a liberal amount of which is necessary for germination and 

 seedling establishment. The method of cutting to be used varies 

 with the density of the stand. 



In comparatively dense stands the mature trees should be removed 

 in two or three cuttings: First, a seed cutting, often unnecessary, 

 consisting in opening up around ash trees (and trees of other species 

 it is wished to favor) to induce them to seed freely; second, a heavy 

 thinning or partial clearance in the year of good seed product ion 

 removing one-quarter to one-half of the volume of the stand; third, 

 removal of the remaining stand a year later or as soon as practicable 

 after reproduction has taken place. Where these cuttings are made 

 with reference to a number of small areas — thinning out around 



