342 



Canadian Forestry Journal, January, ipi6. 



Four Forest Types. 



In describing the forest in this 

 district, it is necessary to describe 

 only four main types. These are 

 determined by altitudinal and mois- 

 ture conditions. 



Yellow Pine Type. — On the lower 

 slopes up to an elevation of approxi- 

 mately 3,000 feet, forming- a very 

 distinct belt around the centre val- 

 ley is the yellow pine type. It is 

 composed of Western Yellow Pine 

 (Pinus Ponderosa) and Douglas Fir 

 (Pseudotsuga Toxitolia) with Yel- 

 low Pine predominating. Both 

 these species are intolerant of shade, 

 the Yellow Pine being exceedingly 

 so, and produce an open stand. 



The annual precipitation in this 

 belt is less than 20 inches, producing 

 a condition of extreme drought in 

 the summer months. This accounts 

 for the presence of the Yellow Pine, 

 and the poor character of the Fir in 

 the type. 



The average stand of merchant- 

 able timber in this type in the Okan- 

 agan is between 3 and 4 thousand 

 board feet per acre, although in 

 some specially favored localities it 

 has been cruised as high as 10 thou- 

 sand. A large percentage of the 

 type however does not produce mer- 

 chantable timber and is suitable for 

 nothing but stock range and the 

 production of cord wood. 



An abundant growth of Pine grass 

 covers the forest floor and affords 

 grazing to cattle and horses. This, 

 however, early ripens, and becom- 

 ing dry and inflammable adds a large 

 factor of danger to the general fire 

 hazard. Fires in this type have not 

 a very great disturbing effect, but 

 as they occur time after time over 

 the" same area, large loss occurs 

 through the enlarging of butt scars 

 and the destruction of seedling and 

 second growth. 



There is probably from 25% to 

 50% of this type occupying land 

 that will eventually be used for agri- 

 culture. This land produces the best 

 stands of Yellow Pine, and therefore 



the amount of this class of timber is 

 likely to be reduced in the very near 

 future, as agriculture develops. 



The Fir Type. 



Above, and bordering on the Yel- 

 low Pine type we have the Fir type. 

 On the lower hills, that is up to 

 3,000 feet, it is often hard to distin- 

 guish between the Fir and the Yel- 

 low Pine types, but with a little in- 

 crease in the elevation, the Yellow 

 Pine quickly thins out, and Fire be- 

 comes predominant. 



This type forms a belt above the 

 Yellow Pine type, from the eleva- 

 tions of 2,500 feet to 4,000 feet. The 

 precipitation at this altitude is some- 

 what higher than in the Yellow Pine 

 type and this accounts for the fre- 

 quent presence of Tamarack, Spruce, 

 Cedar and Lodgepole Pine. 



This is a permanent type. Repro- 

 duction in openings caused by either 

 cutting or firing, is sure and abun- 

 dant. The percentage of Fir is tem- 

 porarily reduced after fire, Lodge- 

 pole Pine taking its place. As Fir is 

 intolerant of shade, it cannot com- 

 pete with the more tolerant Lodge- 

 pole Pine until openings occur. 

 Tamarack and Spruce reproduction 

 is not affected so greatly by the ac- 

 tion of fire. 



The Spruce type occupies the 

 watersheds and plateau regions of 

 the district between the elevations 

 of 3,500 and 7,000 feet. High mois- 

 ture content of the soil is necessary 

 and abundant precipitation. The 

 species found in mixture are Spruce, 

 Lodgepole Pine, Alpine Fir, and 

 Douglas Fir. The species, except 

 Douglas Fir, are all tolerant of 

 shade, and reproduce abundantly, 

 when moisture conditions are not 

 disturbed. 



Fire Reduces Spruce and Fir. 



As the Spruce and Alpine Fir are 

 easily killed by fire and fire also has 

 a disturbing effect on soil conditions, 

 the type disappears after fire and is 

 replaced by the Lodgepole Pine 

 type. At one time probably 25% to 



