摘要:

Distribution of tree height in a Douglas‐fir (Pseudotsuga menziesii(Mirb.) Franco) progeny trial in the Cascades (Oregon) with open‐pollinated (OP) and control‐pollinated (CP) progenies showed an excess of small trees, especially in OP's, compared to normal distributed data. Inbreeding and microsite heterogeneity were causal factors of the skewness in height distributions. Small trees had a disproportionate influence on variance components and heritability estimates. Data truncation of potential outliers was carried out with varying intensity in order to investigate its influence on genetic parameter estimates. Truncation was done by either fixed threshold values or by a proportional elimination of trees from below. Truncated data was analysed either directly or subsequent to a maximum‐likelihood (ML) recovery of the estimated means and variances of the expected completed samples. ML estimates, became increasingly stable as truncation proceeded into the main body of data. Prior to data truncation the estimated additive variance and heritability estimates of the CP population were significantly higher than corresponding estimates for the OP population. However, ML estimates obtained after a proportional elimination of about 12% of the trees in each plot supported the contention of no important difference in additive genetic variance or heritability between OP and CP populations.

ISSN:0282-7581    

DOI:10.1080/02827589109382672

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Artificial freezing tests were performed with two sets of 12 full‐sib families ofPicea abies.Each set was selected from a complete diallel cross performed within a natural population. Significant differences in autumn frost hardiness were observed between the two populations, which originate from the same altitude and longitude approximately 60 km apart. Substantial variation in frost hardiness was observed within both populations. Significant pheno‐typic correlations at the individual level were found between freezing injury and the two traits terminal bud‐set and height growth year one. However, no significant relationships were present between freezing injury and bud‐set at the family level, indicating that bud‐set cannot be used to predict autumn frost hardiness for families.

ISSN:0282-7581    

DOI:10.1080/02827589109382673

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The bacterial species inhabiting Norway spruce(Picea abies(L.) H. Karsten) were investigated, with special attention paid toBacillusspecies. The trees had been inoculated one or five growing seasons earlier with a mixture of fungi and bacteria to observe the interaction of externally introduced microbes with a living tree.

ISSN:0282-7581    

DOI:10.1080/02827589109382674

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Gene diversity and foreign pollen migration into a Scots pine seed orchard in northern Sweden were examined using allozyme markers. The gene diversity and fixation index varied among loci and the average values in embryos over 18 loci were 0.262 and 0.038 respectively. The observed pollen migration into the seed orchard was 30%. Two different methods were used to adjust the observed pollen migration for undetected foreign pollen. The pollen migration into the orchard after adjustment using these methods was 51% and 55% respectively. In addition, sampling procedure and other factors which can influence genetic parameters inferred from allozyme analysis are discussed.

ISSN:0282-7581    

DOI:10.1080/02827589109382675

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

One‐year‐old Norway spruce seedlings were stored at 0°C for four to six months, and then grown for 28‐ days in controlled environment. The dry mass of roots and shoots grown during the period were a measure of root growth capacity and shoot growth capacity. The seedlings were grown in single pots, and the transpiration for individual seedlings was measured by weighing at several occasions during the test period. Seedlings grown the first year with different irrigation regimes and hardened in a climate chamber, and seedlings grown and hardened in a commercial nursery greenhouse were used. The transpiration generally increased with time, but it was reduced after the basal half of the root system was submerged in boiling water for three minutes. The transpiration recovered after six days for seedlings with their root system submerged in boiling water at the start of the experiment, while the transpiration did not recover for seedlings with their root system treated with boiling water after 15 days. Low root growth capacity was recorded for seedlings with an early bud break, and since all seedlings with the root system submerged in boiling water belonged in this group, the effect of the root damage on root growth capacity was insignificant. Shoot growth capacity and transpiration per seedling were lower for the damaged than for the undamaged seedlings. Root growth capacity and transpiration per seedling increased with increased irrigation frequency the previous season, while transpiration per unit of shoot volume decreased with increased irrigation frequency. For the seedlings with late bud break (two weeks), root growth capacity was significantly correlated with the change in transpiration before shoot elongation started. Root growth capacity was, possibly due to its low values, not significantly related to any transpiration parameter for the series of seedlings with an early bud break.

ISSN:0282-7581    

DOI:10.1080/02827589109382676

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The annual increment of Sitka spruce (Picea sitchensis(Bong.) Carr) relative to. crown density was examined at four sites in southwest Britain. Clear differences exist between the relative growth rates of trees which now have thin crowns and the growth rates of trees with dense crowns. Prior to about 1957, trees which currently have thin crowns had higher annual radial increments than trees which currently have dense crowns. Since 1962, trees with thin crowns have tended to have lower radial increments, the extent of the increment depression depending on the degree of thinness of the crown. This pattern closely resembles that found in central Europe where forest decline attributable to air pollution is believed to be a major problem. The timing of the increment declines in both southwest England and central Europe strongly suggests that extreme climatic conditions, particularly winter cold and summer drought, have a marked effect on their development.

ISSN:0282-7581    

DOI:10.1080/02827589109382677

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Pathogenicity tests using 3‐year‐old seedlings ofPinus sylvestrisgrown in the greenhouse and inoculated with 10 000 nematodes demonstrated that an isolate ofBursaphelenchus xylophilusfrom Missouri, U.S.A. and one ofB. mucronatusfrom ǎafAmli, Norway both induced pine wilt in nine of the twenty seedlings used for each isolate. Control plants showed no disease symptoms. The mean temperature in the greenhouse was 5–6°C higher than outside temperature which, may, have been a casual factor in the development of. the wilt disease.

ISSN:0282-7581    

DOI:10.1080/02827589109382678

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Satellite remote sensing has long been understood as a potentially efficient tool for forest management planning. In order to accelerate the integration of these two techniques, a major Nordic research project was launched in 1986. Research teams from Denmark, Finland, Norway and Sweden cooperated in the project, which was coordinated by the Swedish University of Agricultural Sciences and financially supported by The Nordic Forest Research Cooperation Committee (SNS). The results of the research project are being published as four separate articles in the Scandinavian Journal of Forest Research. In this issue, the work done at the Remote Sensing Laboratory of the Swedish University of Agricultural Sciences is reported. A Geo Information System called IRR is defined and implemented as a solution to the problem of integrating satellite remote sensing in a GIS. IRR is the Swedish abbreviation for “interactive editing of raster data”;. A special characteristic of the IRR is that satellite images, maps and verbal descriptions are integrated parts of the data base. Images may be visually interpreted or processed analytically. The IRR emphasizes the following concepts: the marked interactive nature and the powerful editing capabilities. In this context, editing involves everything from editing of raw data to forest management planning. The IRR is for that reason, in the first place, designed as the platform for a powerful forest management planning system and secondly, as a forest mapping system. The system is user friendly and the user interface is designed according to the “point‐and‐click”; philosophy characteristic of Apple personal computers (the threshold of learning the system is comparable to that of a Macintosh personal computer). Although the IRR is basically a raster system, it can yet handle both raster and vector data. Raster data are therefore used where raster suits best and vector data where vectors suit best. A newly developed spatial data model makes it possible to use both vector and raster data simultaneously, without continuous data conversions. The data base of the IRR contains maps, satellite images and verbal descriptions. These data describe the state of the nature at a certain point of time. In forest management planning, these data are used together with knowledge about the forest, to plan actions in the nature in both short and long terms. Knowledge about the forest may either be simple heuristic models in the head of a user or complicated growth models within the system.

ISSN:0282-7581    

DOI:10.1080/02827589109382679

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A rationale for using inductive methodology in remote sensing applied to monitoring of forest resources is given. The approach is tested using a Landsat TM scene of a part of eastern Norway. The image is classified using cluster analysis and the result of the classification is evaluated using Mahalanobis distances. Problems related to the use of statistical verification, Mahalanobis distances in particular, is discussed. A summary of the results with regard to practical applications is given at the end of the article.

ISSN:0282-7581    

DOI:10.1080/02827589109382680

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Bulk densities and chemical properties of surface peat (0–60 cm) of three ombrotrophic pine bogs were measured before and three growing seasons after fertilization. One site was located in each of the countries Norway, Sweden and Finland. Bulk density of peat ranged from 56 in Norway, 78 in Sweden to 130 g dm‐3in Finland. Bulk density seems to vary along a sub‐coastal to sub‐continental gradient for the bog type. When compared to the biological demands of the tree stands, the surface peat stores of extractable K, P and B were low before fertilization. Depletion from the peat on fertilized plots (uptake and/or leaching) were rather high for K, B, Mn and Zn. Especially the sodium borate (borax fertilizer) was susceptible to leaching. Only minor changes occurred in’ pH and cation exchange capacity after fertilization, whereas base saturation was raised, especially in the upper layer (0–10 cm). A high proportion of total K, Ca, Mg, Mn and Zn were on exchangeable sites (63–92%), while P, S. B and Fe were mainly fixed (72–95%). Estimated net carbon loss from the peat at drainage was 100 g Cm‐2year‐1, while at additional fertilization the loss was only 6 g.

ISSN:0282-7581    

DOI:10.1080/02827589109382681

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor