摘要:

The increased concern for environmental values increases the complexity of long‐term forest management planning. Environmental issues have to be dealt with over space and time. By creating links between existing aspatial long‐term forest management models and geographical information systems (GIS), environmental issues can be treated within the forest management planning process. In this article, a spatial decision support system (SDSS) developed by incorporating a forest management planning model into a GIS is presented. A case study is employed to illustrate the usefulness of the SDSS using real data. In order to preserve the water bodies in a forest area, the allowable treatments in areas falling within certain distances of lakes, streams, and swamps were restricted. Treatment schedules were simulated for all stands, and linear programming was utilized to maximize the net present value (NPV) subject to a non‐declining felling path. The NPV was reduced by 6.9% due to the treatment restrictions, and the annual harvest flow was reduced by about 10%. Various thematic maps of future time periods may be produced for subjective evaluation of the results.

ISSN:0282-7581    

DOI:10.1080/02827589709355387

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Some metrics useful for characterizing certain patterns of individual tree crowns are presented. They could be applied in an automated image analysis system for tree species classification in digital high spatial resolution aerial images. The structure‐based measures made use of the internal pattern (also called texture) of individual tree crowns. The infrared layer of colour infrared aerial images was utilized and the different crown patterns were extracted using the second‐order Laplace transform. Skeletonization was used for data compression and to enhance features to be used in the subsequent analysis. The resulting skeleton branches were one pixel thick but they still contained the structural pattern that was identified by the Laplace transform. The skeleton was split into simple segments without branches. The orientation of each individual segment in the tree crown was calculated. A Hough transform technique was developed for analysing whether they collectively had a dominating parallel or radial structural behaviour. It could discriminate clearly betweenPicea abies(L.) Karst, with a typical radial pattern, andPinus sylvestrisL. andBetulasp., sometimes dominated by parallel structures. In our images, the Scots pines showed a more clearly parallel pattern, which was probably caused by a combination of the inclination angle of the sunlight and a slight camera motion during exposure.

ISSN:0282-7581    

DOI:10.1080/02827589709355388

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Nearest‐neighbour regression was tested for generalizing sample tree information in data from the national forest inventory of Finland. The following variables were found to be good regressors: stem diameter, mean diameter, density and age of growing stock, and plot location. The nearest‐neighbour estimator appears to maintain the natural variation of the variables to be estimated well. Reliable volume and height estimates can be obtained even when using only one nearest neighbour. Increasing the number of neighbours improves the accuracy of estimates.

ISSN:0282-7581    

DOI:10.1080/02827589709355389

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Precocious flowering provides opportunities to shorten a breeding cycle. A tree may flower for the first time when sufficient crown development has occurred and there are enough meristems to support both vegetative and reproductive buds. Precocious flowering can be promoted through the use of cultural techniques, such as photoperiod, accelerated growth, gibberellins and water stress. The length of the juvenile phase is dependent on genetic and environmental variables that affect achievement of a minimum size, and is positively correlated with the height of the plants within a family. Selection pressure can be applied successfully to the precocious flowering character, and crossed or inbred lines of precocious flowering progeny can be developed. Various levels and amounts of genetic control have been implicated in the control of precocious flowering.

ISSN:0282-7581    

DOI:10.1080/02827589709355390

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0282-7581    

DOI:10.1080/02827589709355376

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor