摘要:

Mortality of Scots pine(Pinus sylvestrisL.) advance growth seedlings following overstorey removal was studied in nine stands in north Sweden. In each stand, one 40 × 40 m plot was established for each of four different intensities of overstorey removal: 0% (control), 60%, 85% and 100%. Seedlings were monitored on one 18 × 18 m sub‐plot at the centre of each plot for two or three growing seasons following overstorey removal. For seedlings taller than 100 mm, mortality and number of injured seedlings after two growing seasons increased significantly with increasing basal area removal. Seedlings ≤ 100 mm showed the same trend, though not statistically significant. For the height interval > 100 ≤ 500 mm, mortality was not significantly influenced by seedling height. Most of the mortality and the injuries to seedlings were caused byHylobius abietis(L.) andPissodes spp.It is concluded that insect damage to released Scots pine advance growth in northern Sweden is a common problem.

ISSN:0282-7581    

DOI:10.1080/02827589409382826

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Needle mass, length, and nitrogen concentration, and their relation to site index were studied for lodgepole pine(Pinus contortaDougl.) and Scots pine(Pinus sylvestrisL.). Needles were collected at 53 locations throughout Sweden where the two species, of the same age, were growing on adjacent, comparable sites. Sampling was done throughout the growing season, with a pause during the period of most active growth. Needles of lodgepole pine had a higher mass, were longer, and had a lower nitrogen concentration than those of Scots pine. Site index was positively correlated to needle length and weight for both species, and to nitrogen concentration for lodgepole pine. For the characteristics studied, the relative differences between needles of the two species decreased with increasing site index.

ISSN:0282-7581    

DOI:10.1080/02827589409382827

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The effect of soil scarification on decomposition of green Scots pine(Pinus sylvestrisL.) and Norway spruce (Picea abies(L.) Karst.) needles and mineral nutrient release was investigated. The treatments studied were ploughing, disk trenching, mound on inverted humus and untreated control. The study was conducted on two clear‐felled sites with different ground moisture conditions, located in south Sweden. The needles decomposed and released their contents of N and Ca considerably faster on scarified areas than on untreated ones. For P, Mg and especially K, only minor differences between scarified and untreated areas were established. At the wet site, needle decomposition and nutrient mineralization were generally affected to the same extent by all three scarification methods studied. At the dry to fresh site, mounding and ploughing enhanced needle decomposition and nutrient mineralization more than disk trenching. The effect of different scarification methods on the long‐term production capacity of soils is discussed.

ISSN:0282-7581    

DOI:10.1080/02827589409382828

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Selection of winter feeding trees by capercaillieTetrao urogalluswas studied by sampling of needles of Scots pinePinus sylvestristrees browsed by capercaillie and closely situated unbrowsed trees in 5 localities situated in the southern half of Norway. Browsed trees contained higher concentrations of N than unbrowsed trees but no differences in P were found among browsed and unbrowsed samples. Needles eaten by capercaillie were significantly lower in resin content than needles from unbrowsed trees. For tannin, no differences between browsed and unbrowsed trees were found. Results give evidence that capercaillie select needles richest in N when the resin content is low, but when high, the birds select needles low in resin. Thus, both N and resin play an important role in selection of winter browse by capercaillie.

ISSN:0282-7581    

DOI:10.1080/02827589409382829

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Beetles and flat bugs living on the decaying wood of aspen (mainly under bark) were collected during expeditions to Finnish and Russian Karelia. Similar searching methods were used, and a comparable number of sites and trees (about 120) were examined on both sides of the border. The fauna on aspen in Russian Karelia was considerably rich. A total of 21 and 5 rare species were found in Russian Karelia and Finnish Karelia, respectively. Within about twenty working hours in Russ. Karelia we encountered two species considered extinct in Finland(Hylochares cruentatusandCyllodes ater)and five considered endangered or vulnerable(Acritus minutus, Rhacopus attenuatus, Uleiota planata, Cucujus cinnuberinusandAnidus truncatus).We suggest that the high number of rare species at the sites studied in Russian Karelia is attributable to the different management history of the forests, particularly to the abundance and continuity of large, dead aspens. Disturbance caused by logging and leaving the non‐marketable trees has probably increased the diversity at some sites in Russ. Karelia. Aspens killed by notching which are common in eastern Finland had a poor fauna.

ISSN:0282-7581    

DOI:10.1080/02827589409382830

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

From 359 study plots on coniferous forest soil in southern Finland, 232 humus and 359 mineral soil (top 5 cm) samples were taken in 1991 and analyzed for their cation exchange capacity, base saturation, pH, total S content (humus samples only), and extractable Al, Fe, and Mn concentrations in order to assess the impact of acidic air pollution on soil acidity. The main sources of local air pollutants (SO2and NOX) were from the capital region and an oil refinery. Although concentrations of S in the humus layer were 8% higher near the emission sources, it was concluded that air pollution has not resulted in a detectable increase in soil acidity. Mean values for humus layer pH (BaCl2), cation exchange capacity (CEC), base saturation, and extractable Al concentration for the overall study area were 2.9 (0.2), 310(50)meq kg‐1, 48 (12)% of CEC, and 530 (340) mg kg‐1. The respective values for the mineral soil layer were 3.3 (0.3), 56 (19) meq kg‐1, 13 (8)% of CEC, and 320 (130) rngkg‐’. Standard deviations are given in parentheses.

ISSN:0282-7581    

DOI:10.1080/02827589409382831

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

During the winter of 1990–91, fine roots of 2‐year‐old, undercut and wrenchedPseudotsuga menziesii, Larix kaempferi, Pinus sylvestris,andPicea sitchensis(Alaskan, Queen Charlotte Islands, and Oregon) were tested using electrolyte leakage for frost hardiness and tolerance to storage at +1°C for 30 and 90 days as excised roots.Pseudotsuga menziesiiandP. sylvestrisshowed only minor changes in root frost hardiness with a maximum of — 4°C and — 7°C respectively.Larix kaempferiandP. sitchensisdeveloped much greater root frost hardiness;L. kaempferihad a maximum hardiness of — 12°C whileP. sitchensis(Queen Charlotte Islands) reached — 13°C during the winter. The root frost hardiness ofP. sitchensisincreased with the provenance's latitude. There were clear species and provenance differences in the level of long‐term cold‐storage tolerance attained, increasing in the orderP. menziesii, P. sylvestrisandP. sitchensis(Oregon),L. kaempferi, P. sitchensis(Queen Charlotte Islands), andP. sitchensis(Alaskan). In spite of highly significant correlations(p=0.0001) between root electrolyte leakage after cold‐storage and frosting tests, root frost hardiness did not accurately indicate all aspects of long‐term cold tolerance and has limitations as a means of determining safe cold‐storage dates.

ISSN:0282-7581    

DOI:10.1080/02827589409382832

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The larch seed orchard studied is intended to produce interspecific hybrid seed betweenLarix sibiricaandLarix decidua.Only theL. sibiricaclone (half of the grafts) in the orchard was intended to act as the seed parent, and the sixL. deciduaclones are pollinators. The proportion of hybrid seed produced was determined using Mdh3 locus as a genetic marker. The mean percentage of hybrid seed produced by the grafts ofL. deciduawas 93, but that of the hybrid seed produced byL. sibiricawas only 18. The results can be explained by differences in flowering abundance. The grafts ofL. sibiricaproduced several times more pollen than those ofL. decidua.Contrary to the original plans,L. deciduashould be used as the seed parent andL. sibiricaonly as the pollen parent in the studied seed orchard.

ISSN:0282-7581    

DOI:10.1080/02827589409382833

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Thirty‐two southern Swedish families ofPinus sylvestrisL. from a partial 11×11 factorial mating were grown at four night lengths, 3, 5, 7, and 9 h, from the start of their first growth period. At the end of the growth period, the plants were exposed to increasingly longer nights until total growth cessation. During the second and third growth periods, the plants shared the same growing conditions in the growth chambers, starting with two weeks of 6‐h night followed by night prolongation as in the first growth period. The plants from the 9‐h treatment grew more slowly than those from the other treatments in growth periods 2 and 3. The genetic influence of the growing conditions during the first growth period on the height increment during growth periods 2 and 3 was estimated by the female and male by treatment interaction variances. These variance components were relatively small and totally negligible when data from the 9‐h treatment were excluded from the analysis. The data suggest stability in the parents with respect to preconditioning caused by varying photoperiods.

ISSN:0282-7581    

DOI:10.1080/02827589409382834

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

It was hypothesized that maximum living crown removal can be determined from experimental data using linear statistical models. Pruning experiments were carried out in four Scots pine(Pinus sylvestris L.)stands. Zero to nine living branch whorls were removed in three stands in southern Finland, and 0–4.5 m of the living crown was removed in a stand in northern Finland. Only dead branch whorls were removed from the control trees. A total of 517 trees were analyzed. Diameter increment was measured five years after pruning. The growth reduction was statistically significant when 40% or more of the living crown was removed by pruning. According to the linear models, green pruning decreased diameter growth by 0 to 33% at defoliation levels below 40%. This loss in diameter growth is, from an economical point of view, compensated by the knotfree timber resulting from pruning 2–3 years earlier.

ISSN:0282-7581    

DOI:10.1080/02827589409382835

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor