FORESTS OF ROCKY MOUNTAINS FOREST RESERVE 39 



Fire is, on the average, followed by more reproduction than in the case of spruce, 

 on account of the larger number of Douglas fir that survive a fire. The seed-bed 

 conditions induced by the fire are equally favourable to those found after a fire in 

 a spruce stand, unless occupation of the ground by grass has been more or less 

 advanced. In the latter case the grass roots may survive the fire and the growth of 

 the grass be resumed before the seedlings have a chance to start. 



Where forming a portion of present stands, Douglas fir should be given at least 

 equal consideration with other species. On account of the relatively small amount 

 of it, however, it does not constitute a very important problem from the standpoint 

 of natural regeneration. Whenever planting is contemplated, it is a most important 

 species to be considered. The seedlings can successfully compete with grass, and. 

 when they reach a large size, are safer than any other species from wind-fall and 

 fire. 



ALPINE FIR OR ' BALSAM/ 



This is the third species in order of number and fourth in order of merchantable 

 volume. It is short-lived and defective and its timber is knotty and soft, and warps 

 badly, and hence the tree does not rank high in popular estimation. Its chief claim to 

 consideration is in relation to the silvicultural effect of its presence in a stand, and 

 that is generally unfavourable. It resembles spruce in having a deep, cylindrical 

 crown, with a conical top, but it has more horizontal branches. The bole is some- 

 what cleaner, and more cylindrical, without any flaring at the butt. The bark is 

 very thin, and resembles eastern balsam fir in its smoothness, light colour, and 

 blisters. The tree is rather firmly rooted. A considerable portion of wind-thrown trees 

 are broken off a short distance from the ground because of rotten heart, while the 

 roots are not disturbed. The maximum size of alpine fir trees is about 18 inches 

 diameter and 90 feet in height, but the large majority are below merchantable size. 

 The ease with which alpine fir falls a prey to various forms of damage prevents it 

 usually from reaching a great size or age. and from dominating the type of forest 

 except in restricted areas. Like spruce, it is favoured by moisture both in the air 

 and the soil, but nevertheless grows on the dry, thin soils of upper slopes, and is 

 the most common secondary species in pine stands. It is a very tolerant tree hut 

 slightly less so than spruce. Its seedlings bear long suppression and the volunteer 

 growth is often stunted and with a horizontal axis. 



Reproduction. 



The chief point of interest in relation to alpine fir reproduction is its superior 

 ability to reproduce in virgin stands, because that has resulted in the existence of 

 a larger stock of volunteer growth of the alpine fir, or ' balsam/ than of any other 

 species. Seed production and reproduction from seed take place in substantially the 

 same manner as with spruce, and in general with about the same quantitative results. 

 Alpine fir has an additional aid to increase in its numbers in the ability of branches 

 that come in contact with the ground to take root. A vertical shoot starts growing 

 at that point on the branch, and eventually this becomes an independent tree. Many 

 of the suppressed alpine fir in virgin stands are bush-like in character, and have 

 branches down close to the ground. Reproduction by means of ' layering ' is there- 

 fore common. 



After lumbering, aggression by alpine fir is due to the further development of 

 existing volunteer growth, rather than to the starting of new seedlings. The surface 

 of the ground, after the stand is opened up by logging, probably becomes too dry 

 for alpine fir reproduction. 



On account of their small size and thin bark, most of the alpine fir are killed 

 by any fires that may occur, so that reproduction of this species after fire is usually 



