http://www.nofc.forestry.ca/authors/read/15524 Publications by C.F. Robinson en-ca 2010-05-05 00:00:00 MST 2010-05-05 00:00:00 MST webmaster@nofc.cfs.nrcan.gc.ca http://www.nofc.forestry.ca/publications?id=31663 Wed, 05 May 2010 http://www.nofc.forestry.ca/publications?id=31663 http://www.nofc.forestry.ca/publications?id=18040 A trial was initiated in 1953, to investigate the effect of initial tree spacing on red pine (Pinus resinosa Ait.) volume production. Approximately three decades later, in 1982, thinning treatments were added to compare the effects of thinning and initial spacing on volume production. After 45 growing seasons from planting, total volume production (cut + standing volume) mainly was independent of initial spacing and thinning intensity except at the widest (4.3 m +) spacing treatments. Both initial spacing and thinning affected quadratic mean diameter, standing volume and basal area. Knot size was affected by initial spacing with trees at an initial spacing of 3.0 m or wider having a significant number of stems failing to meet utility pole standards due to excessive, large knots. At the time of sampling, 1998, the higher initial densities (1.2 and 1.5 m-spacing) were undergoing significant mortality and falling behind the lower initial spacings in terms of total volume production. In addition, trees at the narrowest spacing were more prone to snow and ice damage. Thinning reduce the time required to meet sawlog and utility pole specifications. The initial spacings ranging from 1.8 to 2.4 m resulted in good growth with high utility pole potential and little mortality. Lower initial spacings required thinning to prevent mortality and maintain good diameter growth. Fri, 16 Mar 2001 http://www.nofc.forestry.ca/publications?id=18040 http://www.nofc.forestry.ca/publications?id=5054 Two of the oldest permanent sample plots (PSPs) in Canada were set up at Petawawa, Ontario (45o 57'N, 77o 34'W) to examine the effect of thinning on the development of natural white (Pinus strobus L.) and red pine (Pinus resinosa Ait.). Field data were collected periodically, starting in 1918 when the stand was 40 years old and continuing for 71 years. Six thinning treatments were completed, beginning in 1918, and then in 1933, 1941, 1959, 1969 and 1989. The intensity of thinning varied through time with 14, 27, 38, 8, 30 and 7% of the basal area removed. The sawlog volume mean annual increment for the thinned plot remained stable at about five m3/ha/yr, but the sawlog volume periodic annual increment for the control declined markedly during the last 10-year measurement period to less than 2 m3/ha/yr. The residual volume was higher in the control; but, if the harvested sawlog volume (264.5 m3/ha) was added to the residual sawlog volume (301.3 m3/ha) for PSP one, then the sawlog production on the thinned plot has been about the same and its residual volume concentrated on fewer, larger and more valuable trees. The level of natural mortality in the control plot (129.7 m3/ha of sawlog volume) was greater than 10 times that in the thinned plot, thereby adding more coarse woody debris to improve wildlife habitat. These two approaches had a major influence on stand development. The approach used will depend on specific stand-level management objectives. Sat, 26 Aug 2000 http://www.nofc.forestry.ca/publications?id=5054 http://www.nofc.forestry.ca/publications?id=4561 Understory 55-year-old white pine (Pinus strobus L.) in mixedwood stands were released in 1971 from an (ca. 80-year-old) overstory of intolerant hardwoods using wheeled skidders in a commercial logging operation. The main aim of the study was to increase the growth and yield of white pine for sawlogs over the following 20 to 30 year period by releasing suppressed pine. Growth of released, healthy white pine was assessed after logging for a range of stand densities (basal areas of 6.9, 11.5, 16.1 m2 ha-1) using suitable control plots and a randomized complete block design with five replicates. Plots were remeasured 10 and 20 years after treatment. By harvesting, much of the natural mortality associated with these stands over the 20-year-period was utilized. Growth responses associated with overstory release were highly significant and demonstrated an 80% increase in sawlog volume increment for treated stands after 20 years. Herb diversity was higher in treated stands and browse potential was not affected. However, white pine regeneration was unacceptably low in all cases. Overstory release increased the natural rate of succession in these stands, but without further management activities or wildfire, the study area will revert to the economically lower-valued hardwoods. Sat, 26 Aug 2000 http://www.nofc.forestry.ca/publications?id=4561