Báo cáo lâm nghiệp:" Effects of competing vegetation on juvenile white spruce (Picea glauca (Moench) Voss) growth in Alaska" pdf

... 2003) Abstract – We examined the impacts of competing vegetation on survival and juvenile growth of white spruce (Picea glauca (Moench) Voss) on 3 units in south-central Alaska and on 3 units in interior Alaska. ... sus- ceptibility of seedlings to fall freezing injury. Height and diameter of white spruce were increased by decreasing competing...

Ngày tải lên: 08/08/2014, 01:21

... types of field vegetation. In addition, mosses com- monly colonise the mineral soil. This study concentrates on the relationship between seed- ling damage and the establishment of vegetation cover ... vegetation control and pine weevil damage 671 colonisation following scarification is an important factor to consider when attempting to reduce pine weevil damage. The vegetation...

Ngày tải lên: 08/08/2014, 01:21

... environmental conditions which could explain the possible changes of vegetation. To guarantee some homo- geneity among the set of studied sites, only one main type of soil was considered: non-hydromorphic ... composition of * Corresponding author: laugusto@bordeaux.inra.fr Effects of tree species on vegetation and soil 825 Therefore, relative values were calculated for each p...

Ngày tải lên: 08/08/2014, 01:21

... old). In great fires recorded in SE Spain, a decrease in the effects of interspecific competi- tion by partial elimination of Cistus monspeliensis L. individ- uals increased survival and growth of ... [42] and competition effects on germination of therophytes described by Pausas et al. [32]. As a conclusion to this study, in spite of the intense modifi- cation of...

Ngày tải lên: 08/08/2014, 01:22

... t.1: clipping of the apex, t.2: clipping of distal buds and leaves, t.3: clipping of distal leaves, t.4: clipping of distal offspring shoot. A white arrow indicates that the corresponding shoot ... species, the branching system consisting of a parent shoot extended in one year and a cohort of offspring shoots extended a year later is characterized by a gradient of increasing...

Ngày tải lên: 08/08/2014, 00:22

... to non-photochemical quenching occurred in response to increasing actinic light and as growth irradiance declined, the ‘quenching shift rate’ declined as well. Overall, Quercus alba seedlings ... quenching with increasing actinic light. The slope of this relationship gives a relative value of the ‘quenching shift rate’ [44]. As growth irradiance declined, the ‘quenching shift rate’...

Ngày tải lên: 08/08/2014, 00:22

... reduction in triose- P utilization and maximal carboxylation effi- ciency in nonmycorrhizal seedlings grown with limiting phosphorus, the leaf P concen- tration of which being ... concentration values found in the needles cover the range observed in different experimentations on pine species where phosphorus supply was controlled and effects on...

Ngày tải lên: 08/08/2014, 18:21

... reports on the direct effects of seedling density on growth in the absence of confounding effects of cell volume. Comparisons of seedling growth in different sized containers ... correlated in Scots pine and Douglas-fir. Specification of seedling size in terms of shoot height alone is not a good measure of seedling size since h...

Ngày tải lên: 09/08/2014, 04:20

... Effects of water deficit on leaf growth and initiation in fast-growing tree species J.C. Metcalfe W.J. Davies 1 J.S. Pereira 2 1 Institute of Environmental and ... production in young E. globulus growing in the field in Portugal can be increased by a factor of 3 under irrigation, and this has been related to an increase in foliage ......

Ngày tải lên: 09/08/2014, 04:20

... generally carried out at the end of the stress application. Effects of saline stress on germination The application of saline stress led to a reduced germination rate. E. alba was ... of free amino acids, but its content in leaves was quite variable depending upon the proven- ance. Conclusion Saline stress reduced growth of plants and in...

Ngày tải lên: 09/08/2014, 04:20