Báo cáo lâm nghiệp: "Long-term evolution of understorey plant species composition after logging in chestnut coppice stands (Cevennes Mountains, southern France)" ppsx

... 9 plant species) . However, ten years after logging, species richness was always significantly higher than before the logging. Figure 2. Evolution of mean species richness after logging of a chestnut ... CONCLUDING REMARKS In our study, the temporary large increase of plant species richness observed especially after clear-cutting, but also after thinning,...

Ngày tải lên: 08/08/2014, 00:22

... projected against EIV for the moisture of the given species. e fitting of the resulting field of points shows a shift in the species composition of the herb layer. e relation of the species position ... indicator value of the given relevé EIV F depends on the value of abundance of each species a j , its indicator value I j and frequency of the respective in...

Ngày tải lên: 07/08/2014, 03:22

... in July than in August (p = 0.001) and September (p = 0.007). It was observed only in stands with the quantity of incoming radiation 1,030 lx and most often in stands with 40–60% of undergrowth ... 17). DISCUSSION All four species of ants inhabit a wider spectrum of biotopes including conifer forests, and thus also spruce forests. e occurrence of individual speci...

Ngày tải lên: 07/08/2014, 10:21

... sensors. A constant thermal energy input has an advantage with respect to variations of sap flow during the day in different tree rings in certain tree species. This kind of sap flow variations does not ... of thermocouples can be applied for long-term studies in almost intact trees. In the present work, infrared thermal images of the dynam- ics of heat field around a heating n...

Ngày tải lên: 07/08/2014, 16:20

... reduction in error of the biomass and volume models (Fig. 5). Examining the sensitivity in un- certainty of the BEF by ignoring the uncertainty in stand age increased the error in young and old ... Impact of different sources of uncertainty on the overall uncertainty of BEFs, when 60% of the intraplot variance is fixed (residual errors of model predictions). In default,...

Ngày tải lên: 07/08/2014, 16:20

... wood density in the innermost rings and increasing it in the outward rings. Until the beginning of cork extraction the accumulation of extractives should contribute to the higher density values found in ... component in the ring width remained particu- larly constant and was not significantly in uenced by any of the studied sources of variation. 4. DISCUSSION In spite of t...

Ngày tải lên: 07/08/2014, 16:20

... differences in the soluble sugar concentration. Light levels in the understory of mature cork oak stands in Spain, can vary from 12 to 70% of incident radiation, depending on the structure of the ... (Ψπ 100 ). The x- and y-coordinates of the first data point of the linear portion of the PV curve corresponded to relative water content at the turgor- loss point (RWC 0 ) and...

Ngày tải lên: 08/08/2014, 00:22

... for the supremacy of this species in the understorey environment of Pinus nigra stands [12, 23, 45]. The presence of Castanea sativa and Picea abies saplings in the understorey of plot 1 and 2 ... canopy opening, moderate thinning) [18]. Finally, although predicting the evolution of the examined stands in relation to the present colonisation strategies is diffi- cu...

Ngày tải lên: 08/08/2014, 00:22

... used to increase the intensity of selection to obtain a higher indirect gain. If felled trees are available, ultrasonic speed measured on log offers a high indirect gain without needing additional money ... means of an “Instron 5582” engine. It is used as the control method. In this way, a global evaluation of a tree is determined by the meas- urements of 12 samples collected in t...

Ngày tải lên: 08/08/2014, 01:22

... beginning of May and ended in mid-June with the peak at the end of May and beginning of June in 2005. In 2006, the flight activity started later in mid-May and lasted to the beginning of July ... higher. In the Nízký Jeseník Hills, the flight activity started at the beginning of May and ended in mid-June with the peak at the end of May and beginning of June in...

Ngày tải lên: 07/08/2014, 03:22