Báo cáo lâm nghiệp: "Multiaged silviculture in North America" potx

... is is increasing the interest in multiaged silviculture in North America as in other regions of the world. An additional factor in uencing current management is the attempts to integrate ... (1965). e southern pine forests in Arkansas have also been a focal point for multiaged silvicultural pro- cedures in the North America. e procedure in these loblolly pine/shortl...

Ngày tải lên: 07/08/2014, 04:20

... again, primarily in those variants of the pot experi- ment in which we compared yellowing spruce seed- lings planted in the soil with intensive impact of spruce litter and green spruce seedlings ... compensation of toxic in uences of manganese and mainly of aluminium. e low content of potassium also indicates the insufficiency of water regimen both in soil and in individual spr...

Ngày tải lên: 07/08/2014, 03:22

... warming resulting from the increase in the volume of carbon dioxide in the atmosphere, particularly over the last decades (F, J 1996). Following the climate analysis in the ... resulting in a 1.3-centigrade increase. D (1998) contends that the climate warming contributes to a dramatic dying process of spruce (Picea abies [L.] H. Karst.) and pine (Pinu...

Ngày tải lên: 07/08/2014, 03:22

... arboricides containing arsenic and diluted in oil products (V et al. 1972). When chemical thinning is used, it is inevitable that the phenomenon of increased danger of insect pest occurrence ... mortality. e elimination of blue spruce by arboricides will require partial inspection of the occurrence of I. amitinus on the stems as well as on logging residues originating from thinn...

Ngày tải lên: 07/08/2014, 03:22

... trans- portation in forest expanses, i.e. skidding tracks, which are basic passages established without us- ing engineering structures and drainage and have rather large longitudinal inclines, which in most ... crawler forwarder wheeled machinery wheeled machinery < 17° crawler machinery wheeled machinery wheeled machinery > 17° crawler machinery crawler machinery crawler machiner...

Ngày tải lên: 07/08/2014, 03:22

... showed that the in- dices obtained by the process of anaerobic incuba- tion cannot be used to assess mineralizing nitrogen in clearings and arable soils. We also obtained by anaerobic incubation ... is to be achieved by determining the quanti- ty of available N at the beginning of growing sea- son; evaluating potentially available N by diff erent methods; determining nitrogen absorbed by...

Ngày tải lên: 07/08/2014, 10:21

... use in forestry practice, three methods that eliminate existing seasonal fluctuations are proposed. Seasonal indexes seem promising since they enable converting the observed germination indicators ... average. Germination capacity Germination capacity is a quantitative charac- teristic of the whole process of germination giving relative number of germinated seeds after 21 days of germinat...

Ngày tải lên: 07/08/2014, 10:21

... virgin forest. e testing of the in u- ence of the altitude revealed its great in uence in the growth stage. In the optimum and breakdown stages a statistically significant difference in the index ... of the virgin forest is very heterogeneous in this altitudinal zone. e number of the individuals from natural re- generation (individuals of the height below 130 cm) is declining i...

Ngày tải lên: 07/08/2014, 10:22

... (Populus euramericana Guinier). Diameters at breast height were respectively 15 cm, 20 cm and 25 cm. Chestnuts were growing in a private forest in south of France, mani in a tropical rainforest in French Guyana (South ... poplar in Kyoto university experimental forest (Japan). Experiments on mani and chestnut involved measurements of RGS and longitudinal drying shrinkage, and were p...

Ngày tải lên: 07/08/2014, 16:20

... containing four trees. One systematic thinning was carried out (by removing every second tree in a row) in 1995 at the Platon site and in 1996 at the Windsor and Saint-Ours sites. A subset of three ...  Saint-Anselme, ˛ Windsor,  Saint-Ours. of change, as the hybrid poplars tested are still young and have not yet matured and achieved a corresponding increase in wood density. For i...

Ngày tải lên: 07/08/2014, 16:20