摘要:

Differences in cold acclimation were evaluated for detached needlesof six Pinus contortaDougl. and sixPinus sylvestris(L.) provenances originating from latitudes 55° to 68° N in western Canada and northern Sweden. The needles were collected in a Swedish field trial and freeze tested at various temperatures in the range of ‐ 6°C to ‐ 29°C on four occasions from August to October. Temperatures causing 50% discolored (dead) needle tissue were considered a measure of the level of cold acclimation. Provenance variation in needle injury was evident during the whole test period. Variation within species may largely be explained by the latitude of provenance origin, the more northern, the better the frost tolerance. The cold acclimation of lodgepole pine was comparable to that of Scots pine of approximately eight to five latitudes more northern origin from August to October.

ISSN:0282-7581    

DOI:10.1080/02827589209382723

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The frost hardiness of dormant stem cuttings of cultivatedSalix,representing a range of species and clones, was determined. Plants were subjected to a standardized artificial hardening regime, and frost hardiness was determined using a standardized freezing method. All the cuttings survived exposure to temperatures of at least ‐ 85°C. Freezing tolerance was concluded to be the most important winter survival mechanism for all cultivatedSalixspecies. Primordia in the axillary buds, the secondary cambium and the root initiation cells all tolerated the imposed low‐temperature stress. Field observations, together with the experimental results, suggest that winter damage is because of incomplete winter acclimation rather than inherent inability to develop adequate tolerance to low temperature stress.

ISSN:0282-7581    

DOI:10.1080/02827589209382724

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

InPinus sylvestristhere are two chemotypes—those with (2R,3R)‐trans‐taxifolin 3´‐O‐ß‐D‐glucopyranoside ( =T) and those without this substance. Trees containingTalso contained the biochemically related 3´‐O‐ß‐D‐glucopyranoside of eriodictyol and ampelopsin (EandA,respectively). Analyses ofE, TandAwere performed with HPLC and/or TLC. A rapid extraction with aqueous ethanol followed by TLC was used for identification ofT.The segregation inT‐rich andT‐free trees was determined in twenty‐nine progenies from crosses or selfings inPinus sylvestris.Except for six selfed trees which were assumed to be due to illegitimate fertilization, all data supported a monohybrid inheritance of the presence ofTinP. sylvestrisneedles, withT‐free trees being recessive homozygotes. The concentration ofE, TandAin trees containing these flavonoids is modified by other genes. The analyses of 240 trees forAandEare consistent with a monohybrid inheritance.

ISSN:0282-7581    

DOI:10.1080/02827589209382725

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

During the growing seasons of 1985–88, red spruce(Picea rubensSarg.) seedlings were exposed repeatedly in field chambers to sulfuric and/or nitric acid mist in the range of pH 2.5 to 4.5. Hydrogen ion, sulfate, and nitrate concentrations in mist were within the range found in cloudwater of the northeastern USA where high‐elevation spruce forests are declining. After the period of exposures, seedlings remained outdoors and buds were sampled in the autumn to determine effects of mist treatments on the number of developing needle primordia. Current‐year foliage was sampled from autumn to spring for measurement of cold tolerance by freeze‐induced electrolyte leakage (FIEL) and buds were scored for degree of bud break in the early spring. In the 1985–87 experiments when 16‐hour overnight mist events were continuous, there were few statistically significant effects of acidic mist on needle primodia development, foliar FIEL, and bud‐break. However, in the 1988 experiment when 16‐hour overnight mist events were intermittent rather than continuous and acidities fluctuated among events, sulfuric acid mist decreased the number of needle primordia in September and October relative to the other treatments. Acidity of mist increased FIEL in October. Sulfate and nitrate content of mist appeared to influence these effects of acidity on FIEL differently depending on level of cold tolerance and duration of time since the period of exposures to mist. Bud‐break in May was not significantly affected by prior mist treatments. Responses to acidic mist were similar among provenances that were obtained from different locations in the northeastern USA, although provenances differed in phenological development and FIEL. Mist deposition to the soil medium was minimized or avoided in these experiments; therefore, we conclude that foliar FIEL of red spruce seedlings is vulnerable to effects of direct contact of acidic mist with foliage. To relate results of these controlled experiments to cloudwater and decline of red spruce trees in the northern Appalachian mountains, the following information is needed: the frequency of wet‐dry cycles in the forest; fluctuations in acidity and sulfate and nitrate concentrations among and within cloudwater events; the specific patterns of temperature changes that lead to winter injury; and the relationship between FIEL and freezing damage to foliage for both seedlings and mature trees.

ISSN:0282-7581    

DOI:10.1080/02827589209382726

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The current annual increment (wood volume) of stands of evergreen conifers on a research site in Sweden, was found to be significantly correlated with the maximum ratio of shoot to leaf silhouette area of shade‐acclimated shoots (Rmax). Neither the slope nor the intercept of the regression was significantly different from that published earlier relating maximum mean annual increment of British stands toRmax.Moreover, a strong correlation between wood volumen increment andRmaxalso occurs when data from four countries are combined. Wood density was not significantly correlated withRmax. Harvest index for stand grown conifers more than 25 year old, was also not correlated withRmax. Estimated net biomass production (excluding fine roots) was significantly correlated withRmax(R2= 0.82,F= 17.7). These new analyses could not be used to disprove the hypothesis that variation in shade shoot structure of evergreen conifers has a measurable effect on maximum biomass production.

ISSN:0282-7581    

DOI:10.1080/02827589209382727

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A set of 101 clones structured in 14 full‐sib families of hybrid Larch were compared on one test site at age 8. At that age, clone within family variation was an important part of the total variance for both vigour (15.2%) and stem form (26.7%). While the family component was negligible for vigour (3.0%), the latter was significant for stem straightness (13.9%). Variance components for total height seemed to be stabilized at age 8. Clonal heritabilities for both traits were high and genetic gains as high as 9.7% and 32.6% were expected for vigour and stem form respectively through direct selection. Nevertheless, severe unfavourable correlations between these traits have been detected. Simulation of index selection showed that still non‐negligible gains might be expected on both vigour and stem form when constraints were put on stem form quality of selected clones to be similar to that of check seedlings. Interest of the clonal way for hybrid Larch propagation was discussed with respect to both genetic improvement and diversity.

ISSN:0282-7581    

DOI:10.1080/02827589209382728

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Autumn frost hardiness of offspring from clones (originating from 66.0–68.8° N) in six southern (62° N) and one northern (66.5° N)Pinus sylvestrisseed orchards in Finland, was evaluated. One‐year‐old seedlings derived from open pollinated grafts of young, intermediate, and fairly mature age, and natural stand seedlings, were artificially freeze tested. The northerly located orchard produced the least injured offspring. There were no significant systematic differences between age classes. Neither were there any indications of decreased freezing injury with later age classes. The family variance was significant in four orchards. The estimated injury levels of orchard offspring were, in general, closer to those of natural stands in the neighbourhood of the orchard than natural stands at the place of clonal origin. It is suggested that not only differences in mother clone hardiness but also clonal differences in pollen contamination rate caused the observed family variation.

ISSN:0282-7581    

DOI:10.1080/02827589209382729

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A simulation model of pine regeneration is presented, based on earlier models and research for natural regeneration of Scots pine in Finland. The model is stochastic, reflecting the unpredictable variation in regeneration results observed in nature. Geographic area, site and stand characteristics and soil preparation affect the simulated regeneration result. The model predicts the amount and quality of seed crop, germination and predation of seeds, and survival and growth of seedlings. The effect of parent trees on seed dispersal, and growth and survival of seedlings is accounted for. At the stand level, the model gives results similar to empirical measurements. The simulation example provided illustrates the effect of density and spatial distribution of the parent tree stand on the regeneration result.

ISSN:0282-7581    

DOI:10.1080/02827589209382730

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Mortality ofPicea abiesseedlings caused byHylastes cuniculariuswas studied by analysing damage reports and by repeatedly inspecting 12 000 individually marked seedlings in 59 plantations. The findings indicated thatH. cuniculariuscaused more damage in the northern parts of Sweden than in the more southern parts. Feeding byH. cuniculariuswas the most frequent cause of spruce seedling death in plantations during 4 to 6 years after cutting of the previous stand. Although accumulated seedling losses sometimes exceeded 30%, yearly loss rates were generally moderate. The long period over which damage can occur is one of the reasons whyH. cuniculariushas rarely been identified as an important cause of seedling mortality in spruce plantations.

ISSN:0282-7581    

DOI:10.1080/02827589209382731

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The relationship between moose damage and the stocking density of young Scots pine stands was investigated in the study. A regeneration area with an initial density of 14 700 seedlings ha‐1was thinned to densities ranging from 2 000 to 11 000 seedlings ha‐1. Part of the stand was left unthinned. The study area was a typical winter foraging habitat for moose in southern Finland, the moose density being over 2 individuals 100 ha‐1.

ISSN:0282-7581    

DOI:10.1080/02827589209382732

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor