排序方式： 共有4条查询结果，搜索用时 317 毫秒
1
1.
Growth and mortality in underplanted tree seedlings in response to variations in canopy closure of Norway spruce stands 总被引：2，自引：0，他引：2
Lof Magnus; Karlsson Matts; Sonesson Kerstin; Welander Torkel N.; Collet Catherine 《Forestry》2007,80(4):371-383
Six broadleaved tree species and Picea abies (L.) Karst. wereplanted under spruce plantations of varying densities, in Sweden.Treatments included control (994 stems ha–1), dense (538stems ha–1), sparse (294 stems ha–1) and gap (0stems ha–1) overstory treatments. There was an increasein height and diameter growth from control to sparse overstorytreatment of all underplanted tree species except for ash (Fraxinusexcelsior L.) and Norway maple (Acer platanoides L.). Site conditionsmay have hampered the growth of these species, as well as wildcherry (Prunus avium L.). Both oak (Quercus robur L.) and sprucehad greater growth in the gap treatment, relative to the othertreatments. Insecticide application did not influence seedlinggrowth or survival. The performance of beech (Fagus sylvaticaL.), lime (Tilia cordata Mill.), spruce and oak was consistentwith shade tolerance ranking. Beech and lime had a very highsurvival rate, even under the densest canopy. The growth andmortality of ash, maple and wild cherry differed significantlyfrom what was expected. This experiment demonstrated significantvariation in interspecific growth and mortality between sevenplanted tree species in relation to canopy density. Correctsite and species selection is crucial when underplanting inshelterwood systems. 相似文献
2.
For the last 8 years, EPPO has run a European Panel on diagnostics, which has developed regional standards on diagnostic protocols. Nearly 60 such standards have now been approved, and are in active use in EPPO countries. In 2004, the Interim Commission for Phytosanitary Measures (ICPM) of FAO, in reviewing global needs for International Standards for Phytosanitary Measures (ISPMs), recognized that there is a strong interest in developing diagnostic protocols for all IPPC contracting parties. Such protocols would support the harmonization of detection and identification procedures worldwide, contribute to greater transparency and comparability in the diagnostics of regulated pests, and assist in the resolution of disputes between trading partners. In addition, such protocols would constitute a very good material for technical assistance. In 2004, the ICPM adopted a mechanism for more rapid development of ISPMs in specific areas, suitable particularly for diagnostic protocols. A Technical Panel to develop protocols for specific pests was also established and met for the first time in September 2004. A format for international diagnostic protocols was prepared, together with a list of priority pests. 相似文献
3.
4.
1