FORESTS OF KOOKY MOUNTAINS FOREST RESERVE 25 



Fire also reduces the commercial value of the timber on an area over which it 

 has passed, even though the trees are harvested in a short time. A direct reduction 

 is seldom caused in the volume of material that can be obtained from the stand. 

 The damage is caused in two other ways; first, as a result of drying out, the wood 

 checks, mainly in a tangential direction, and this lowers the amount of lumber that 

 can be sawn out; again, in two or three years, the sapwood stains green, which lowers 

 the grade of the lumber or necessitates an entire waste of the sapwood. 



Besides killing the present stand, fires burn off the humus and litter on the 

 ground exposing the bare soil. In spruce stands on moist flats this may be accom- 

 plished only in patches, or, if conditions at the time are very moist, a continuous 

 layer of humus may be left on the ground. On an area where spruce reproduction 

 was following a recent fire in a fairly satisfactory manner, there being about 600 

 seedlings per acre, it was found that sixty per cent of the total area had the ground- 

 cover practically intact and no reproduction ; fifteen per cent had the top layers 

 burned off and fair reproduction, and twenty-five per cent had the bare soil exposed 

 and uniformly good reproduction. This tendency for good seed-bed conditions to 

 occur in small patches results in the growth of second-growth spruce oftenest in small, 

 dense clumps, instead of the trees being uniformly spaced throughout the stand. In 

 a pine stand where a fire had been of an intensity just sufficiently great to kill the 

 trees without burning or scorching the crowns, fifty per cent of the surface showed 

 the soil burned bare. Such a condition produces a young stand of much more favour- 

 able density for rapid development than where a heavier fire produces an over- 

 crowded stand. Bare soil is, particularly for pine, the best seed-bed; and pine seeds 

 germinate with difficulty on any humus layer, even where spruce seeds will start 

 satisfactorily. 



The effect on the supply of seed is important also. With pine, a light fire, 

 which merely kills the trees, does not at once affect the seed supply ; but, when the 

 cones and twigs dry out, the cones open and many fall to the ground as the dry 

 pedicels and twigs are broken by the wind. When the fire is hot enough to scorch 

 the tops, the cones open directly and many fall in a short time, thus immediately 

 putting a large amount of seed in a position to germinate. In general, the heavier 

 the fire, the more rapid and the denser the reproduction, since the seeds are brought 

 to the ground more quickly and the soil is more completely exposed. 



With spruce, the first effect of the fire is to burn up existing supplies of seed. 

 Spruce seeds are shed in a short period immediately after opening and do not 

 remain in the cones on the trees as do pine seeds. The fire, therefore, burns all these 

 seeds with the humus and also all the young seedlings. If at the same time all the 

 old trees are killed, there is obviously no chance for spruce reproduction, no matter 

 how favourable are seed-bed and other conditions. As a matter of fact the noticeably 

 small proportion of spruce in second-growth stands is directly caused by this dis- 

 advantageous effect of the fire. Reproduction of spruce after a fire takes place under 

 two conditions; first, on moist sites where the fire has been light and some spruce 

 trees have been left alive to supply seed, or adjacent to green stands at the edges of 

 burned areas where there may be a resulting stand of dense, pure spruce, since pine is 

 at a disadvantage on account of the large amount of humus left on the ground under 

 these conditions; second, on areas where pine reproduction is predominant, there are 

 usually scattered spruce seedlings which have started either from seed left in unburned 

 patches of humus or blown in from a distance. 



In pure spruce stands where fire burns all the existing seed, kills all the old 

 trees, and the absence of pine prevents possibility of reproduction of that species, the 

 grass which temporarily occupies practically all burned-over areas continues as the 

 permanent occupant of the ground and a meadow is formed. Such a meadow is 

 illustrated in Plate 3. Even where there is a small amount of pine seed available, 

 the large amount of humus left unburned on the moist spruce sites makes the seed- 

 bed so unfavourable to pine that the seed fails to germinate. Most of the mountain 



