. An annotated list of the important North American forest insects. Forest insects. Biology and Control of the White-Pine Weevil 25 1800 \ \ /500 \ ?J \ \ Q /200 \ ^ \ ^ 900 \ ^ \ 600 \ 1 300 \ \ - ^_ n /O 20 60 90 /OO 50 60 70 In yeaKs Figure 13. of white pine at different ages The reduction in number is due to the natural thinning that results from competition (After Hawley, Practice of Silviculture) 30 '40 Aqe, NUMBER OF TREES PER ACRE IN A FULLY STOCKED STAND From these data it is apparent that if a density of from 1200 to 1500 trees per acre is maintained throughout the early years of the
. An annotated list of the important North American forest insects. Forest insects. Biology and Control of the White-Pine Weevil 25 1800 \ \ /500 \ ?J \ \ Q /200 \ ^ \ ^ 900 \ ^ \ 600 \ 1 300 \ \ - ^_ n /O 20 60 90 /OO 50 60 70 In yeaKs Figure 13. of white pine at different ages The reduction in number is due to the natural thinning that results from competition (After Hawley, Practice of Silviculture) 30 '40 Aqe, NUMBER OF TREES PER ACRE IN A FULLY STOCKED STAND From these data it is apparent that if a density of from 1200 to 1500 trees per acre is maintained throughout the early years of the rotation, and a fully stocked stand thereafter (figure 13), then the loss resulting from the attack of the white-pine weevil will be at a minimum. On the other hand, if a fully stocked stand is not maintained, a serious loss may be expected. This conclusion has been independently verified by Peirson (1922), so that the facts of the case appear to be well established. From the foregoing discussion it is evident that there are two possible courses of silvicultural procedure that may be followed for protection of white pine from the weevil. In mixed forests on good soil, this tree can be grown. Figure 14. tree in dense stand outgrow- ing WHITE-PINE-WEEVIL INJURY The leader was killed by weevils, and the lateral gained the lead and formed a nearly straight trunk. The remnant of the leader still projects from the side of the trunk. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Craighead, Frank C. (Frank Cooper), 1890-; Perry, George S; Snyder, Thomas Elliott, b. 1885; Hopkins, A. D. (Andrew Delmar), 1857-1948; MacAloney, Harvey John, 1896-; Graham, Samuel Alexander, 1891-; Peirson, Henry Byron, 1894-; Herrick, Glenn W. (Glenn Washington), 1870-1965; Britton, Wilton Everett, 1868-1939; Tanaka, T; Sanders, J. G;
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Keywords: ., bookauthorhopkinsadandrewdelmar, bookcentury1900, bookdecade1900
