摘要:

The location of Capercaillie lekking sites was compared in forest mosaics of different level of fragmentation. In north Finland the stand characteristics of the lekking sites did not differ from those of randomly selected stands in the 1950s judged from forestry maps and stand registers. In the 1980s, when forestry had considerably altered stand structure, lekking stands were older, larger and had a higher timber volume than random stands. These features evenly changed from the lek centre to the distance of 4 km, to which distance the adjacent areas were assessed. Southern and central Finnish analyses, based on topographic maps, showed that the proportion of forest distinctly decreased with increasing distance from a lek centre, up to a distance of 1–1.5 km. The average patch size of lekking stands were largest in the north (where both cut areas and remaining stands are large) and smallest in central Finland dominated by fine‐grained forest landscape. The results are discussed in terms of landscape ecology and forestry planning.

ISSN:0282-7581    

DOI:10.1080/02827589409382856

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

In Sweden, long‐term forecasts of timber yields have traditionally dealt with the production of timber, without consideration of costs and revenues. A system for long‐term forecasting (HUGIN) has been further developed with incorporation of calculations of costs for logging and silviculture together with revenues from timber and pulp wood. The forecasts of HUGIN are based on sample plot data from the Swedish National Forest Inventory. After the specification of alternative silviculture and logging programs in HUGIN, the user can study costs, revenues and number of man‐days for each program. By using quality functions and price lists, the HUGIN system calculates the highest possible revenue for the individual tree by optimizing the division into assortments. The HUGIN system will be improved further in the future to include calculations of road transport costs, improved quality functions and revenues from other forest resources than timber.

ISSN:0282-7581    

DOI:10.1080/02827589409382857

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The basis for this study was that forest inventories, as well as other forestry activities, should be performed in such a way that a maximum present net value is attained. Consequently, both the inventory cost and the expected loss from erroneous decisions, caused by data errors, should be considered in the decision about which inventory designs should be used. Investigations of the optimal sampling intensities in stand level sample plot inventories were made under the assumptions of stumpage values being deterministic as well as stochastic. The methodology involved sampling simulation and simulation of stumpage value fluctuations. It was found that the optimal inventory intensities should be slightly lower in the stochastic case, the reason being that harvest decisions were largely influenced by the current stumpage values. The study, however, only addressed the problem of deciding the optimal point of time for clearcutting in cases when no harvest level restrictions over time were present.

ISSN:0282-7581    

DOI:10.1080/02827589409382858

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:0282-7581    

DOI:10.1080/02827589409382859

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor