CONVERSION OF DENSE LODGEPOLE PINE STANDS IN WEST-CENTRAL BRITISH-COLUMBIA INTO YOUNG LODGEPOLE PINE PLANTATIONS USING PRESCRIBED FIRE .2. EFFECTS OF BURNING TREATMENTS ON TREE SEEDLING ESTABLISHMENT

The ecological effects of different treatments used to convert dense l ogdepole pine (Pinus contorta Dougl.) stands into young lodgepole pine plantations are being determined. The treatments used were bulldozing the trees and either broadcast burning the slash or bulldozing the sl ash into windrows, which were then burned. Burns were conducted under different fuel moisture conditions and state of fuel curing to achieve four classes of fire severity. Lodgepole pine seedling survival was a ffected by both site preparation and fire severity. Five years after o utplanting, survival was significantly (p < 0.05) greater for areas be tween windrows (81%) than for areas beneath windrows (65%) or for broa dcast-burned areas (67%). Survival was greatest after 5 years for low- severity burns in fresh slash (80%) compared with low-severity burns i n cured slash and higher severity burns (67-69%). Seedling total heigh t and height increment 5 years after outplanting were significantly gr eater (p < 0.05) in areas beneath windrows than in areas between windr ows or in broadcast-burned areas. However, stem diameter was similar a mong all site preparation treatments. Fire severity had no effect on l odgepole pine total height, height increment, and basal diameter growt h in any year after outplanting. Lodgepole pine seedling foliar nutrie nt levels were generally consistent with trends in seedling growth in that foliar concentrations generally tended to be higher when growth w as higher (in the case of site preparation); however, no significant d ifferences in growth were found (in the case of fire severity). This s uggested that foliar nutrient levels could at least partly explain see dling growth results. Surface mineral soil (0-15 cm) chemistry exhibit ed similar trends to seedling foliar chemistry when site preparation t reatments were compared, but not when fire severity classes were compa red. This was attributed to foliar chemistry being controlled by facto rs other than soil chemistry alone.