WESTERN" YELLOW PINE IN OREGON. 7 



found in a squirrel cache. Undoubtedly a considerable proportion 

 of the seed crop is eaten by animals, since the seed is large and 

 attractive. In Oregon, yellow-pine seed is larger than it is farther 

 east. The number of seeds to the pound from eastern Oregon trees 

 is between 8,000 and 9,000. A bushel of unopened cones will usually 

 yield about 1^ pounds of seed. 



GERMINATION. 



The seed germinates fairly frerely, but in Oregon not until the 

 spring following its dissemination. Laboratory tests of clean seed 

 show that from 60 to 85 per cent of it is fertile, and that most of it 

 germinates between four and eight weeks after sowing. 



Field studies indicate that young seedlings are most abundant in 

 the exposed spots in the forest, such as on scabby ridges, where the 

 mineral soil is naked. Here germination may be the best, but the 

 mortahty of the seedlings the first year is the largest. 



In certain parts of Oregon, particularly on the very dry pumice 

 soils of the upper Deschutes Basin, it is noticeable that a very large 

 proportion of the seedlings come up in clumps, from 2 to over 50 being 

 crowded into a space as large as a half dollar. It has been suggested 

 that these clumps originated where a cone accidentally became buried. 

 But such is not the case in this particular locality. They have come 

 from bunches of seed which were buried by provident chipmunks. 

 (See PL II.) Some counts made in Crook County of the reproduction 

 in the forest showed that 85 per cent of aU. the 1-year-old seedlings 

 were in these chipmunk-sown groups. Much more seed must be 

 sown broadcast by the wind on the surface than is accidentally left 

 in these chipmunk caches, yet it is evident that the seed which is 

 buried has a very much better chance of germination than that 

 which hes on the surface. This is particularly so on the drier and 

 looser soils, where the chipmunks may actually be considered an 

 aid to reproduction. The competition in growth between the seed- 

 lings in these clumps becomes very keen early in their lives and they 

 thin out rapidly, though it is not unusual to find ten or a do2;en seed- 

 lings four feet high growing from a single hole. One unusual in- 

 stance was noted where 29 fourteen-year-old saphngs were Uving in 

 a cluster. One-year-old seedlmgs in these chipmunk-sown clumps 

 have been found to be less likely to succumb to drought than soUtary 

 seedlings, perhaps because they give each other protection. 



It is not infrequent to find a dense row of seedlings, a veritable 

 natural hedge from 25 to 75 feet long, located in the path of mineral 

 soil and ashes left after a fallen tree had burned up. The cause of 

 these hedges is not perfectly understood. 



