摘要:

We investigated the long‐term net dynamics of N, P, S, K, Ca, Mg and Mn in decomposing litter. Green and brown needles of Scots pine(P. sylvestrisL.) lodgepole pine(Pinus contorta),as well as green and brown leaves of white birch(Betula pubescens)and leaves of grey alder(Alnus incana)were incubated for up to 4 years in a 130‐year‐old Scots pine forest. The concentrations of N and S increased linearly with accumulated mass loss, also P concentrations increased linearly after an initial leaching. Moreover, the rate of increase in N concentrations appeared to be proportional to the initial concentration. After the increase, N and P concentrations reached a phase in which they remained constant or declined slightly. Concentrations of Mg and K decreased with accumulated mass loss, especially in litter types with high initial concentrations of these elements. For Mn the pattern was similar but less pronounced. The relationship between Ca concentrations and accumulated mass loss was largely negative, resembling a negative X2function. Absolute amounts of nutrients decreased linearly with litter mass loss once a net release had started. This applied to all litter types and nutrients with the exception of Mn release from grey alder leaves.

ISSN:0282-7581    

DOI:10.1080/02827589509382860

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Stand differentiation, heritabilities and genetic correlations in 16 growth, bud and branch traits inPinus contortasubsp.latifoliawere studied for two growth periods in the greenhouse. Data for analyses were based on 116. open‐pollinated families from 33 stands in one breeding region in central Alberta, Canada. Family effect was significant at the 1% level of probability for all traits. The narrow‐sense heritabilities (h2) from 0.43 + 0.09 to 0.71 + 0.12 for traits of absolute height and diameter were the highest reported for growth traits in this conifer. In contrast, h2varied between 0.15±0.06 and 0.33 ± 0.08 for bud, branch and growth increment traits. Except for relative branch length, all traits showed convariation with the other traits. Levels of heritability and genetic correlation suggest that selection procedures that exploit additive genetic variance and covariance might be practised, provided there would be high juvenile‐mature correlation for this sample ofP. contortasubsp.latifolia.

ISSN:0282-7581    

DOI:10.1080/02827589509382861

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Seedlings representing offspring from 46 Swedish natural standsof Pinus sylvestris(L.) from latitude 63° to 68° and altitude 75 to 675 m were artifically frost hardened and tested for autumn frost hardiness using artifical freeze testing in a programmable freezing chamber. A clinal variation in frost hardiness was observed over latitude. Altitude had no effect on the frost hardiness. The results are discussed in relation to the reproduction‐ and migration biology ofP. sylvestris.

ISSN:0282-7581    

DOI:10.1080/02827589509382862

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We describe DNA fingerprinting of willows(SalixL.) by polymerase chain reaction (PCR). We amplified genomic DNA of 15 putative clones inSalix eriocephala, S. exigua, S. miyabeana, S. roridaandS. sachalinensis,and in 4 ramets of a clone in each ofS. petiolarisand 5.eriocephalawith the M13 universal primer (5´‐TTATGAAACGACGGCCAGT‐3´). A total of 19 PCR fragments (bands) were observed, but each clone had 4 to 9 bands. Fourteen of the 15 clones had unique banding profiles that distinguished each other. The remaining clone fromS. eriocephalawas identical to a clone of the same species. Banding profile was reproducible among ramets of theS. petiolarisclone, but minor differences in staining intensity in 2 of the 6 bands were observed among ramets of the 5.eriocephalaclone. A dendrogram of relationships showed that clones of the same species grouped together.

ISSN:0282-7581    

DOI:10.1080/02827589509382863

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Frost hardiness of tissues along the length of the stem and the root was investigated in first‐year black spruce (Picea mariana(Mill.) B.S.P.) seedlings. Frost hardiness of 1 cm long stem and root segments was evaluated based on Index of Injury, calculated from post‐freezing electrolyte leakage. Frost hardiness was tested approximately weekly beginning seven weeks after seedlings were transferred from an 18 to a 10 h photoperiod, both at day/night temperatures of 26°C/16°C. Trees were transferred to temperatures of 10°C day and 5°C night at a 10 h photoperiod after a further 18 days. Frost hardiness was greater at the terminal bud and least at the root tips. Although shoots were generally more frost hardy than roots, differences in hardiness along the stem and root axes were gradual, rather than abruptly differing at the shoot‐root interface. All tissues, including root tips, increased in frost hardiness after conditioning for 18 days under short photoperiods (10 h) and warm temperatures (26ˆC/16°C, day/night). Under cold temperatures (10°C/5°C, day/night) all tissues, excepting the root tips, tolerated — 16°C with little subsequent electrolyte leakage.

ISSN:0282-7581    

DOI:10.1080/02827589509382864

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Evaluation was made of the effect of precommercial thinning in 13–15 year old Norway spruce (Picea abies (L.) Karst.),on the incidence ofHeterobasidion annosumin residual trees, more than 20 years after thinning. Five sites in southern Sweden were studied with the following treatments at each site: unthinned plot and plots thinned to 600, 1 000, 1 400, 1 800 and 2 500 stems ha−1. Only three trees out of 450 investigated, were found to be decayed. None of these trees were found to be infected byH. annosumas an effect of precommercial thinning. Control measures to prevent decay caused byH. annosumin residual trees do not appear warranted for precommercial thinning of young, planted, Norway spruce stands.

ISSN:0282-7581    

DOI:10.1080/02827589509382865

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A material of 1156 observations was used to develop two Norway spruce(P. abies(L.) Karst.) stand volume functions for western Norway. An additive model initially based on a polynomial of second degree was found to be most suitable. The independent variables were stand basal area, Lorey's mean height, the product of basal area and mean height, and the square of the mean height.

ISSN:0282-7581    

DOI:10.1080/02827589509382866

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Field studies were conducted during three years to determine the vertical (height level) and horizontal (distance from stand edge) distribution of flyingNeodiprion sertifer(Geoffroy) males in a non‐outbreak population. Sticky traps baited with synthetic female pheromone (25, 35, 75‐diprionyl acetate) were used in a mature stand of Scots pine (Pinus sylvestrisL.) in Central Europe (southern Bohemia). The vertical distribution was distinct; more males were caught in traps at 9.0–12.5 m height (crown stratum) than in traps at 2.5 or 0.5 m above ground. The horizontal distribution was rather uniform inside the stand, with only small differences between catches near the stand edge ( < 30 m) and inside the forest. These data show that the main flight ofN. sertifermales in high pine stands takes place at the crown level. Implications for the use of pheromone traps in monitoring programs are discussed.

ISSN:0282-7581    

DOI:10.1080/02827589509382867

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The history of a pine dominated(Pinus sylvestrisL.) forest stand in northern Sweden was documented by applying dendrochronological crossdating technique on stumps, down logs and living trees within a small (0.1 ha) sample plot. The forest stand was exploited for the first time in the early 19th century. At that time it was an old‐growth pine forest. Prior to the exploitation the forest was subjected to forest fires at regular intervals of 40–50 years. During the 19th century the large diameter pines were logged and a new stand was naturally regenerated following a forest fire towards the end of the century. In the 20th century, active forest management was introduced and the naturally regenerated stand has been subjected to thinnings and fertilizations, the result being an ordinary pine forest due for clearcutting within the next 10–20 years. The results suggest that the dendrochronological method used provides an important tool for detailed description of the natural history and the exploitation history of a boreal forest. The quality and availability of stumps are crucial factors as well as a general knowledge of the local forest history.

ISSN:0282-7581    

DOI:10.1080/02827589509382868

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A method is presented for prediction of the present net value (PV) of timber production, based on satellite data and subjectively inventoried forest stand data. Multiple regression analysis was used for predicting the PV. This method has the advantage that predictions of the PV can be made using any kind of existing stand data. The precision of the estimate of the PV, however, depends on the information available in the forest stand database. In the study a combination of Landsat TM data and subjectively inventoried site‐index explained about 75% of the variance, which was equal to the case when all subjective ground stand data, excluding TM data, were used to predict PV. This result and results from other data combinations suggest that Landsat TM data might be useful for forest management planning.

ISSN:0282-7581    

DOI:10.1080/02827589509382869

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor