38 BULLETIN 1437, U. S. DEPARTMENT OF AGRICULTURE 
its propagation on lands which are not producing any other forest 
crop and which are not needed for agricultural purposes. 
Mature stands present no special problem except that care be 
taken to keep out fire and to prevent indiscriminate cutting or slash- 
ing when the land is not needed for other purposes. After the stand 
has reached about 50 years of age its growth is on the decline and 
efforts should be made to realize upon it before growth ceases en- 
tirely. Thinnings for cordwood, poles, etc., if properly made, should 
in no way injure the stand, and Avill probably result in increased 
growth of such trees as are liberated. 
Immature stands, from the seedling stage up to 30 or 40 years of 
age, need above all protection from needless cutting or slashing. 
These young stands have an exceedingly rapid growth in volume; 
they can furnish merchantable material at 40 or 50 years of age, 
besides yielding before this time a considerable quantity of small 
material suitable for firewood, etc. 
Where alder occurs in pure stands, as in the coast region of Oregon 
and Washington, it is largely a temporary type, which will give 
place under natural conditions to more tolerant and longer-lived 
coniferous species, chiefly Douglas fir or Sitka spruce, which are 
generally better suited to these hillsides. Found usually on severely 
burned areas, where the conifer stand has been destroyed and the 
soil impoverished, the alder with its humus-producing leaves and 
twigs and nitrogen-producing roots 7 builds up the soil, bringing 
back to the area the conditions favorable to the growth of conifers. 
Alder stands of this character should be protected so far as practi- 
cable, and utilized before decadence sets in. 
For sustained crop production red alder warrants careful consid- 
eration. In seed production it is very prolific, and from all observa- 
tions will restock burns and recently cut-over lands naturally to a 
satisfactory degree within a few years after the timber has been 
removed. Therefore, natural reproduction can undoubtedly be de- 
pended upon for the new crop. Comparatively young trees bear con- 
siderable seed and scatter it widely, so that a cut-over area may 
reseed satisfactorily from a few well-placed trees not needed for 
timber, assisted by others bordering the cutting. Some care, how- 
ever, must be taken to plan the cutting operations against the pre- 
vailing wind so that seed from the adjacent standing timber will 
blow onto the cut-over area. 
It is not thought necessary to burn the slash left upon the ground, 
as a silvicultural measure; nor from the standpoint of fire protec- 
tion is burning generally needful, for alder slash customarily decays 
very rapidly, and most of the stands are in areas of comparatively 
low fire hazard. 
The financial return that can be expected from growing red alder 
is problematical, depending largely on the future value of the 
stumpage. Assuming that the yields at maturity, or from 45 to 55 
years, are correctly indicated in Table 15, averaging 25,000 board 
7 Examination of tbe nodules on the roots of red alder by the Forest Products Labora- 
tory shows that they contain nitrogen-fixing bacteria. See Johnson, H. M., Alnus 
oregona : its value as a forest type on the Siuslaw National Forest. Jour. Forestry 15 : 
981-987. 1917. 
