f 
38 BULLETIN 1200, U. S. DEPARTMENT OF AGRICULTURE. 
same condition has been noted on other areas, and it often accounts 
for the establishment of the cedar and-hemlock even among Douglas 
fir seed trees. The cedar and hemlock seeds are less sought after by 
_ rodents when Douglas fir seeds are available for food. | 
The influence of scattered seed trees of Douglas fir was found to 
be lhmited (Pl. X), although gradually seedlings get a foothold in 
the immediate vicinty of the trees, as shown by Table 17. Scattered 
seed trees evidently will not insure a complete stand for some time, 
and it is doubtful if the stand would be complete until the seedlings 
reach seeding age and restock the remainder of the area. Therefore, 
in this gradual process of seeding an area, protection should be given 
not only to scattered seed trees, but also to scattered young growth. 
(PlKeby: 
TABLE 17.—Average number of Douglas fir seedlings per acre on areas burned 
two or three times, with scattered seed trees lefts 
| Average || Average | Average 
Distant from seed | number of Distant from seed | numberof || Distant from seed | number of 
trees. | seedlings trees. seedings | trees. seedlings 
per acre. peracre. | per acre. 
Agchiain2e2 ai brs: 106 || 15 chains........... 0 | 99 Ghainsas eee 0 
WCWANSe 5.2 5s on 20S P16 chains’. 22232 bE Q?|| 30 chains... s<25. 266 0 
DICHAIH Shree nos sae oe 53a) Pe GHalnSses eee e OQ jpsl ehainsesey soe a 
AICHSIN SES Seas nee 60) |2t8 chainsk ss. eee (PS Chibi San ee 0 
HIChaINS sees ee oo MAS et Gichainse sees ee OuiSsachaims eer. sees 0 
Gichainsas=. tose. See 0:||220 eHainse see 0. |} 34 chains... 2.2.2... 0 
7 clintns 2000. @) 20 chains) oa). 92 || 35 chains........-.. | 0 
Bienains SO 5io Ie) Sus. O ):22 echains- 2.2 2. &: Ol) 36iehains/ 22 7s 9352 | 0 
OTE RATHS ieee oh ee Ua ASiel ames ee Oe HWP BVA ANGIE Se 0 
Oreharmssten: bees eA) 80)" || 24.chains: 22223225 ON pS8iehains: 22a. s eee 16 
Ivehainsee os} asec ZG 2oiChain See Sense Ouli7e9ichainss sae 0 
PICHON os sone cas On e2oGhains = ease 20h) a0 Chains eee seas 0 
HS Chainse Aja eo eke Os 27icharmnsee~=2 oe - 0 | 
WA CHAINS Sia = See See te O) 228 chains. .2e. fees 0 | 
1 Based on 162-rod square plots examined annually for 5 years, and on 3.8 miles of belt transect line. 
2 1 chain equals 66 feet; 40 chains equal one-half mile. 
The foregoing facts brought out in regard to the origin of young 
growth in the Pacific Northwest lay the foundation for the methods 
required to keep the forest lands productive. They show also that 
present methods of slash disposal and fire control tend to devastate 
forest lands, and furthermore, that the methods now used can be 
made to conform to the requirements for securing young growth 
with practically no additional expense. 
MIGRATION. 
The preceding chapter emphasized the point that the greater part 
of the reproduction is due to seed that was within the burned or cut 
area before the fire or cutting and that other seed-distributing 
agencies are only incidental in restocking forest lands. However, 
denuded areas are slowly reclaimed through migration, and the 
species are changed within the forest through succession and compe- 
tition. The effect of each of these factors on the composition and 
establishment of the Douglas fir forests is pointed out in the follow- 
ing discussions. 
Migration of Douglas fir is a very slow process. On burned areas 
young growth appears in unexpected places; but, wherever it has 
been possible to get a complete history of the area, the explanation 
of such stands has usually been. that there was some source of seed 
within the area and that some seed had remained viable in spite of 
