摘要:

To investigate the fungal flora associated with the spruce bark beetleIps typographusin an endemic area, beetles were collected during the flight period in six locations in Trøndelag, Norway. The beetles were inoculated into fresh Norway spruce logs, and the frequency of different species was monitored by fungal isolation from bark and wood. The most common species wereOphiostoma bicolor, O. penicillatum, O. polonicumand a previously undescribedGraphiumspecies, the same species which were the most important associates ofI. Typographusin an epidemic area in southeastern Norway. The frequency of the primary invader,O. polonicum,was, however, lower in Trøndelag, which may indicate that this species is less frequent in endemic areas than in epidemic areas.

ISSN:0282-7581    

DOI:10.1080/02827589309382760

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The effects of a large holiday resort on the distribution and range use of semi‐domesticated reindeer were studied in the three most important habitat types in Saariselkä, eastern Finnish Lapland. In two of these habitats the relative reindeer densities increased in winter, when outdoor activities declined reaching density equal to the average for the herding association at a distance of about 10 km from the holiday resort. In summer, male reindeer adapted better than females to the proximity of the holiday resort. The feeding site preferences of the reindeer during winter followed, in general, the normal pattern in areas with little human interference. Although the economic value of the range loss appeared small compared to the gain from outdoor enterprises, better planning is needed to avoid the harmful effects of recreation on reindeer management.

ISSN:0282-7581    

DOI:10.1080/02827589309382761

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This article demonstrates that the opportunity cost (return forgone) of cutting principles imposed by the Swedish forest policy is economically significant. The Swedish Forestry Act of 1979 recommends a management strategy for sustaining high yields of valuable timber referred to here as the Balance Strategy. However, the Forestry Act allows for a range of different forest management strategies. The Act establishes both a minimum cutting volume for a ten‐year‐period and a maximum final cut area referred to here as the Minimum and Maximum Strategies, respectively. These strategies were compared to a management plan, referred to as the Economic Strategy, for minimizing the opportunity cost for the forest owner. Based on data from a recent forest management plan, a simulation model was used to predict yields and economic returns for a period of one hundred years. The results show that at a 4% interest rate the Economic Strategy produces a gain of approximately 8200 SEK ha‐1. The Economic Strategy, however, emphasizes volume and its implementation results in a forest far different from that developed under the Balance Strategy, in which quality timber is also produced. The Economic Strategy may also have less favourable effects on biodiversity, conservation of the natural environment and the recreational value of the forest.

ISSN:0282-7581    

DOI:10.1080/02827589309382762

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0282-7581    

DOI:10.1080/02827589309382763

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Soil and fine‐root sampling were carried out in a Norway spruce (Picea abies(L.) Karst.) stand with high levels of atmospheric deposition of sulphur and nitrogen in south‐western Sweden. Living and dead fine roots in both LFH‐ and mineral horizons were excavated from soil cores. The bulk and rhizoshpere soil concentrations of Al, Ca, Mg, Fe, K and pH were measured in water extracts. The magnesium concentration was significantly higher in the rhizosphere than in the bulk soil except for in the deepest horizon. The Ca/Al‐ratio increased with depth in both the rhizosphere and bulk soils while it decreased with depth in fine roots. The ratio was lower in dead than in living fine roots. The amount of both living and dead fine roots decreased with depth. The necromass/biomass ratio was highest in the 10 to 20 cm mineral soil horizon.

ISSN:0282-7581    

DOI:10.1080/02827589309382764

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Embryogenic suspension cultures of sitka spruce (Picea sitchensis) were successfully cryopreserved. The best method for cyropreservation as demonstrated by regrowth tests was: 1) preculture in medium containing 0.4 M sorbitol and pretreatment with 5% (v/v) DMSO (dimethylsulfoxide), 2) freezing the cultures at a cooling rate of 0.5°Cmin‐1to —40°C followed by transfer to LN (liquid nitrogen). After thawing in a waterbath at 45°C the growth rates of cell cultures cryopreserved by this method were equal to growth rates of untreated unfrozen cultures. The cryopreserved cultures gave rise to mature somatic embryos which developed cotyledons, roots and shoots 3–4 months after thawing.

ISSN:0282-7581    

DOI:10.1080/02827589309382765

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Competition effects between six varieties of Scots pine in a field trial were studied from age 5 to 15. The spacing was 1.5 *1.5 m. Different plot sizes were compared with respect to varietal means, coefficient of variation, and “degree of genetic determination”;, as a substitute for heritability, Differences between plot types were explained well by the hypothesis of a characteristic balance between above‐ and belowground competitive bias, changing over time. ANOVA of data from contrast plots, consisting of pairwise varietal mixtures, allowed estimation of direct varietal, and associate varietal effects. The associate effect was suggested as a measure of the belowground share of competition‐induced variance. Height growth was less sensitive to competition, especially aboveground, than were diameter and volume growth. A competition adjustment method, based on height differences, was applied. The feasibility of this method was related to plot design and competition dynamics.

ISSN:0282-7581    

DOI:10.1080/02827589309382766

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The occurrence of fungi in the underground parts of 1‐ and 2‐year‐old conifer stumps (Pimis sylveslrisandPicea abies) was studied in two clear‐felled areas of eastern Uppland in Sweden, and most fungal isolates were identified to species.

ISSN:0282-7581    

DOI:10.1080/02827589309382767

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A 26‐year‐old hybrid aspen trial has been evaluated for growth capacity, survival, quality and damage. The trial was situated in southern Sweden and included purePopulus tremuloidesMICHX. andPopulus tremulaL. and both kinds of hybrids between these species. The major part of the trial consisted oftremula × tremuloideshybrids and the analysis was focused on an 11 × 7 factorial containing 37 hybrid families.

ISSN:0282-7581    

DOI:10.1080/02827589309382768

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

We studied the changes in vascular plant vegetation in the first five years after final felling of a mature Norway spruce (Picea abies(L.) Karst.) forest on a productive peatland. Vegetation changes following clearcutting and selective cutting (shelterwoods with the density 140 and 200 stem ha‐1) were compared. The total cover of the understory increased three times on the clearcut and more than twice in the shelterwoods. The relative decrease of the three most common species was from 73% to 3% on the clearcut and 79 to 28% under the shelter trees. Six of the 16 most common species in the mature forest almost disappeared on the clearcut. In contrast, in the shelterwoods, few species decreased and twelve of the most common species remained the same or increased their cover.

ISSN:0282-7581    

DOI:10.1080/02827589309382769

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor