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Báo cáo lâm nghiệp: " The influence of different overstory removal on planted spruce and several broadleaved tree species: Survival, growth and pine weevil damage during three years"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: " The influence of different overstory removal on planted spruce and several broadleaved tree species: Survival, growth and pine weevil damage during three years" | Ann. For. Sci. 62 2005 237-244 INRA EDP Sciences 2005 DOI 10.1051 forest 2005015 237 Original article The influence of different overstory removal on planted spruce and several broadleaved tree species Survival growth and pine weevil damage during three years Magnus LỎFa Robert PAULSSONb Dan Rydbergc Nils Torkel WELANDERa a Swedish University of Agricultural Sciences Southern Swedish Forest Research Centre PO Box 49 230 53 Alnarp Sweden b PO Domaregatan 7C 256 59 Helsingborg Sweden c Regional Forestry Board South Gotaland PO Box 234 291 23 Kristianstad Sweden Received 5 February 2004 accepted 7 July 2004 Abstract - The influence of different overstory removal on herbivory by the pine weevil to seedlings was studied in a field experiment. Four overstory treatments with middle aged Norway spruce in combination with or without insecticide treatments were applied. Seedlings of the following seven tree species were planted in each of the four blocks Acerplatanoides L. Fagus sylvatica L. Fraxinus excelsior L. Picea abies L. Karst. Prunus avium L. Quercus robur L. and Tilia cordata Mill. The seedlings were monitored through the 2001-2003 growing seasons. Highest survival was found among seedlings planted in the overstory treatments with 15 and 20 light in the understory whereas best diameter growth in seedlings was found in the clearcut. Overstory trees of Norway spruce decreased herbivory from pine weevil considerably among underplanted seedlings and the pine weevils fed significantly more on planted Norway spruce seedlings than on all broadleaved tree species. The following rough preference order was obtained 1 Norway spruce 2 beech and oak 3 ash cherry lime and maple. The influence from the insecticide treatment was minor. Therefore during the conversion of Norway spruce monocultures into mixed species stands using overstories the use of insecticides against pine weevil is not needed. forest restoration forest transformation insect damage regeneration shelterwood .