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1.
Abstract

Economic weights are needed for genetic selection to weigh different traits in multitrait breeding. The aim of this study was to develop, for commercial forest species, a model for estimating economic weights of survival relative to volume production per unit area. The model takes the patchiness across a stand and the polygenic nature of the factors influencing survival into account and consists of three submodels. The first submodel calculates volume production and a patchiness coefficient, using a production area that is divided into smaller units or production cells. The patchiness coefficient is defined in the model as the variance of survival between the production cells. The second submodel calculates volume production as a function of survival and the patchiness coefficient. The third submodel is a threshold model, which transforms the genetic change in survival from the observable scale to the underlying (liability) scale, thus providing a measure of economic weight. The model behaviour was studied using growth functions for Pinus sylvestris L. in northern Sweden. Both the absolute value of survival and its patchiness coefficient affected the projected production per unit area. When survival was higher than 50%, the relative economic weight of survival increased with decreasing survival and an increasing patchiness coefficient. The relative economic weight of survival was found to be insensitive to changes in site index and harvesting age, but was clearly affected by different initial stand densities.  相似文献   

2.
Abstract

The effect of various biological, genetic, economic and management factors relevant to advanced generation seed orchard establishment was investigated using numerical estimates for Scots pine (Pinus sylvestris L.) in Sweden. Factors considered were planting density, rate of genetic advance in the breeding population, timing of first seed collection, seed value, seed production cost (stratified to establishment, annual management, cone harvest and seed extraction), orchard rotation age and contamination level. The developed model demonstrated its utility in studying and evaluating various economic and biological options associated with advanced generation seed orchard establishment/turnover. Sensitivity analyses demonstrated the robustness of the developed model through various arbitrarily changes in genetic gain advances, establishment, management and seed production, particularly those associated with cone harvests from upper crown and costs. The Swedish Scots pine case study produced results supporting faster turnover of seed orchard generations (30 vs 40 years) with shorter orchard lifespan (early start of seed cone after 8 years vs 15 years) delivering higher gain through minimizing the genetic gain differential between the breeding and production populations and allowing the capture of this gain for inclusion in the seed orchards. Orchard planting densities of 400 and 600 grafts per hectare produced similar results with marginal differences, and the latter was recommended for future orchard establishment.  相似文献   

3.
A combined species – provenance – family experiment with Scots pine and lodgepole pine was planted in Canada and Sweden. One aim of the experiment was to evaluate the two species’ sensitivities to pathogens and insects 25 years after establishment in their non-native continents. In Canada, Scots pine had better average survival than lodgepole pine, but survival rates among trees from the best seed-lots were equal. In Canada only western gall rust infected Scots pine to some extent, and mountain pine beetles attacked and killed Scots pine more frequently than lodgepole pine. At one site in Sweden, lodgepole pine had higher survival rates than Scots pine, whether evaluated as an overall average or with data from only the best surviving seed-lots. At the other Swedish site, the species’ survival rates were equal, largely since moose damage was much more frequent on lodgepole pine than on Scots pine. Adaptation to local conditions seemed to be important in the resistance of stem breakage caused by heavy snowfalls. The exotic species generally seemed to resist the new threats, but more serious damage by mountain pine beetle on Scots pine than on lodgepole pine in Canada demonstrates possible drawbacks when using exotic species which are phylogenetically similar to native.  相似文献   

4.

New silvicultural regimes with high within-stand competition require new functions for estimation of standing stock and growth of biomass components, since the allometry of trees is changed by light competition. This paper presents functions for estimation of the aboveground biomass dry weights for stem wood, stem bark, branches and leaves of young (diameter at breast height <10 cm) Scots pine (Pinus sylvestris L.), Norway spruce [Picea abies (L.) Karst.] and birch (Betula pendula Roth. and Betula pubescens Ehrh.) trees growing in dense mixed stands. The functions were derived from a sample consisting of 84 Scots pine, 43 Norway spruce and 66 birch trees from six stands in northern Sweden with high stand densities (>10000 st ha-1). The logarithmically transformed power function displayed a good ability to stabilize the variance of dry weights and showed a good fit to the material (0.37< R 2 <0.99). A comparison with the most commonly used biomass functions in Sweden today showed that they overestimated the weight of stem wood and branches, while the weight of foliage was underestimated. The nature of these discrepancies suggested that the precision of biomass estimations might also be improved for young trees at wider spacing.  相似文献   

5.
Lodgepole pine is native to western North America, but it is also planted as a fast-growing alternative to Scots pine in Sweden. The production of these two species, when grown as native and as exotic species, was compared in a transcontinental two-species provenance experiment. The tests were planted in 1986 on five sites in northwestern Canada and two sites in Sweden, and included full-sib families, half-sib families, seed orchard collections and natural stand seed collections of both species. After 25 years, lodgepole pine produced 48% more volume (m3ha?1) and had 27% higher survival than Scots pine at one Swedish site, and had similar volume production and survival at a second. In the five Canadian sites, Scots pine produced on average 22% more volume than lodgepole pine. The variation between sites was, however, large. This higher volume of Scots pine in Canada could be due to higher survival (+28%) and less frequent damage; but higher top height for lodgepole pine in Canada indicated higher potential productivity. The results indicate that an exotic species may produce more than the native species, possibly thanks to higher survival, but it is also possible to increase production with successful population selection of the native species.  相似文献   

6.
The objective of this study was to analyse the conditions for forest production on open, low‐production peatlands in Sweden with respect to climate, and water and nutrient regimes. The study focused on survival and growth of Scots pine (Pinus sylvestris L.) seedlings, planted 18 yrs ago in five experimental areas evenly distributed between south and north Sweden. Different ditch spacing and NPK fertilizer treatments were combined systematically in all experiments. Survival was positively correlated with temperature sum, fertilization and drainage intensity. Tree growth was not influenced by variations in temperature sum after merely draining, but in combination with fertilization, growth was strongly correlated with climate. In the southern experiments, fertilization increased stand growth eight to nine times, whereas stands on the northern sites did not respond to fertilization. The most important fertilizer element was P. The application of N had no effect on growth. More intensive drainage increased stand growth by 60%. In the southern areas, height development in the most intensive drainage and fertilizer treatments indicates a mean annual increment of 6–7 m3 ha?1, and no sign of decline in growth was seen. Turf‐planting had positive effects on both survival and growth, especially in less intensively drained plots. A large proportion of damaged trees was observed in the experiment. The frequency of damaged trees was positively correlated with treatment intensity but negatively correlated with temperature sum. The results show clearly that merely draining is not sufficient for successful afforestation of low‐production peatland sites. Fertilization by P and K is a necessary prerequisite, but the effect of fertilization varies with climatic conditions, probably owing to the amount of plant‐available N.  相似文献   

7.
Predictions of damage risk from snow and wind at sites using tree characteristics of Scots pine (Pinus sylvestris L.), were made using a subset of data from permanent sample plots within the Swedish National Forest Inventory (NFI). The plots were sampled twice at five-year intervals between 1983 and 1992. A logistic risk assessment model was developed using data originating from 286 plots, dominated by Scots pine (> 65% of basal area), within one county situated in the boreal zone in northern Sweden (Västerbotten). The model was evaluated with NFI-data from two other counties, one adjacent to Västerbotten (Västermorrland, 99 plots), which is also in the boreal zone, and one (Kalmar, 138 plots) in the hemi-boreal zone in southern Sweden. In each plot, measurements at first inventory of tree characteristics for the largest undamaged sample tree, and measurements at second inventory of damage from snow and wind on all sample trees were used to develop a logistic model that predicts the damage probability for each site. The best predictors were upper diameter (ud, diameter at 3 or 5 m) and the ratio of height/diameter at breast height (rhd). According to the model calculations, the overall damage probability never exceeded 0.26 for any of the sample plots used for model development. At a given ud the probability of damage is higher for a site with trees of low rhd. The fit of the model was better for the adjacent Västernorrland county than for the southern county, Kalmar. This inferior predictability was explained by differences in tree characteristics between Kalmar and the other counties. The results show that it is possible to predict damage from snow and wind at a site by using only single tree characteristics.  相似文献   

8.
Abstract

The quality and accompanying value of Scots pine (Pinus sylvestris L.) lumber varies markedly in the Nordic countries. Consequently, tree bucking has a great impact on the economic result. The objectives of this study were (1) to analyse which knot characteristics usually reduce pine lumber sawn from the butt-logs to the next quality grade, (2) to determine the most appropriate characteristics that could be used in predicting lumber quality, and (3) to develop models that could be used in practice for predicting the probability of certain quality grades. The study was based on field experiments and test sawing data on 100 Scots pine stems from south-western Finland. Since the results showed that the maximum dead knot is the most crucial knot characteristic when the first cross-cutting point is determined, models were created that predict the height of the first dead knot that lowers grade A to B (B-grade dead knot). Both early growth rate and dead branch height should be measured to predict pine butt-log quality. Early growth rate seems to be appropriate in predicting between-stand variation, while dead branch height is appropriate for predicting within-stand variation.  相似文献   

9.
Mortality of Scots pine (Pinus sylvestris L.) 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 by Hylobius abietis (L.) and Pissodes spp. It is concluded that insect damage to released Scots pine advance growth in northern Sweden is a common problem.  相似文献   

10.
The breeding of the pine shoot beetle (Tomicus piniperda) after thinning of young Scots pine stands in late autumn, and subsequent shoot damage, were studied in southern, central and northern Finland during three successive years (1977–79). No distinct increase in the attack density or beetle population was observed on the felled trees during the study period. Shoot damage on the standing trees remained low, and was not considered to have any marked negative effect on tree growth or further development of the pine stand. No noticeable difference was found between the different parts of the country. The economic importance of beetle damage resulting from late autumn thinnings was estimated to be low.  相似文献   

11.
Seedlings of different provenances of Scots pine (Pinus sylvestris L.), lodgepole pine (Pinus contorta Dougl., var. latifolia Engelm.) and Norway spruce (Picea abies (L.) Karst.) were planted in three Scots pine shelterwoods (125, 65 and 43 stems ha−1) and a clear-cut, all in northern Sweden. The sites were mounded and planting took place during 2 consecutive years (1988 and 1989). The solar radiation experienced by the individual seedlings was determined using a simulation model. Height development of the seedlings was examined during their first 6 years after planting. During the final 3 years of the study, height growth of Norway spruce was relatively poor, both in the shelterwoods and the clear-cut area. Height growth of lodgepole pine was significantly greater than that of Scots pine, both in the shelterwoods and the clear-cut. In contrast to Norway spruce, Scots pine and lodgepole pine displayed significantly greater height growth in the clear-cut than in the shelterwoods. For all three species in the shelterwoods, regression analyses showed that height growth was more strongly correlated with the distance to the nearest tree than with the amount of radiation reaching the ground, i.e. growth was reduced in the vicinity of shelter trees. Therefore, we conclude that the significant reduction in height growth of seedlings of Scots pine and lodgepole pine in Scots pine shelterwoods was partially caused by factors associated with the distance to the nearest shelter tree. Because the substrate was a nitrogen-poor sandy soil, we suggest that root competition for mineral nutrients, especially nitrogen, accounts for the reduction in height growth.  相似文献   

12.

Reducing competition by point cleaning may be an attractive alternative to conventional precommercial thinning in forestry. In this study, survival and development of main stems of Scots pine (Pinus sylvestris L.) following point cleaning were examined in a mixed stand of mainly Scots pine and birch (Betula pendula Roth and Betula pubescens Ehrh.) in northern Sweden. Treatments studied were: no precommercial thinning, conventional precommercial thinning, point cleaning of all secondary stems, and point cleaning of only the secondary stems that were higher than the main stem, within a radius of 0.8 m from the main stem, respectively. A randomised complete block design with three replicates was used. Measurements taken 13 growing seasons after these treatments showed that conventional precommercial thinning was the best treatment for retaining Scots pines as main stems. However, conventional precommercial thinning resulted in the poorest timber quality of the remaining Scots pines in terms of stem taper, thickest branch diameter and relative live crown height. In conclusion, point cleaning has to be followed by a complementary cleaning operation if the objective is to retain Scots pines as main stems in such mixed stands.  相似文献   

13.
The patterns of current‐year shoot, needle and terminal bud elongation in seedlings of three Scots pine (Pinus sylvestris L.) and three lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) provenances were compared during the third and fourth growing seasons after planting. Lodgepole pine produced longer shoots and buds than did Scots pine, mainly because lodgepole pine formed more stem units and elongated at a faster rate. Stem unit length and the duration of shoot and bud elongation differed relatively little between species and provenances. Lammas or polycyclic growth occurred in some lodgepole pine provenances, but not in any Scots pine provenance, and was associated with enhanced shoot elongation. Needle elongation commenced earlier, proceeded at a faster rate, and was greater in lodgepole pine than in Scots pine, but ceased about the same time in all species and provenances. The heat sum required to attain 50% of final length was lower for shoots and needles in lodgepole pine than in Scots pine, and for shoots in northern provenances than in southern ones. Mitotic activity in the apical meristem of the terminal bud, which occurred less than one week after the seedlings were free from snow, started and ceased about the same time in each species, but was higher in lodgepole pine than in Scots pine early in the shoot elongation period.  相似文献   

14.
Results are presented from a 30‐year‐old Scots pine provenance trial series covering all Sweden. Variation in total yield is studied and the effect of transfer on this trait. The results show that significant differences exist between provenances in almost all trials. The variance component for provenance effects is about 60% of the total variation. Repeatabilities are found to be high, indicating reliability of data. Based on a response surface model and a contour plotting procedure, transfer functions for southern and northern Sweden respectively, are built. For southern Sweden, a transfer of ±1° combined with an altitudinal downward transfer of 100–200 meters, is proposed. In northern Sweden, no optimum transfer range is found. The function, however, shows that a southward and upward transfer, in combination, gives remarkable gains in total yield.  相似文献   

15.
Abstract

Contamination by southern pollen is a considerable problem in Scots pine (Pinus sylvestris L.) seed orchards established with northern clones. This study investigated whether the contamination was due to the competitive superiority of southern pollen by carrying out competition trials using mixtures of pollen from northern and southern populations of Scots pine. Trials were performed in a southerly seed orchard established with clones originating from northern populations. Seed paternity (siring) was determined through the analysis of allozyme variation. Southern genotypes sired significantly more seeds (76%) than their northern competitors and across all mixed-pollen crosses. Maternal genotype had no effect on seed siring success. The mean flower abortion rate was lower in southern pure-pollen crosses and mixed-pollen crosses than in northern pure-pollen crosses. The results show that local pollen may induce high levels of background pollination in southern seed orchards composed of northern genotype grafts. These results must be taken into account when aiming to produce suitable reforestation material for northern areas.  相似文献   

16.
Eleven 27 to 29‐year‐old Scots pine provenance trials were studied in areas 400 m or less below timberline in northern Sweden. Functions describing geographic variation in the local provenance showed that survival as well as height and volume growth decreased with increasing latitude and elevation. Survival decreased by 7% per degree increase in latitude and 16% per 100 m increase in elevation. Beeting increased the survival by on average 2.4%, but less at high latitudes and altitudes. Tree height and volume per hectare decreased by 0.8 m and 15 m3, respectively, per degree increase in latitude and by 1.3 m and 24 m3, respectively, per 100 m increase in elevation. Transfer functions for provenances at different sites showed that the effect of latitudinal transfer on survival was reduced close to timberline. On average, a southward transfer of one latitudinal degree increased survival by about 7%, which is lower than in previous studies. No altitudinal transfer effects on survival were detected. Volume/ha was increased by southward transfer in northern parts of the area. Spacing had only a slight effect on performance and did not influence the functions presented.  相似文献   

17.
The blister rust of two‐needle pines in Europe is caused by the rust fungus, Cronartium flaccidum (Alb. Schw.) Wint. There are two races of the fungus: One host‐alternating and another pine‐to‐pine race. The latter race is considered to be more common in northern Sweden. The impact of this rust on growth of Scots pine (Pinus sylvestris L.) was investigated in three selected stands in northern Sweden. Radial stem increment was reduced 40–70% by severe attacks and 20–40% by minor attacks. The reduction of stem volume growth was probably greater. The faster growing trees seemd to be more severely attacked. Trees growing on poor soils appeared to lose almost as much growth capacity from a minor attack as from a severe attack.  相似文献   

18.
Management implications associated with two different silvicultural strategies in two Spanish pine forests (Scots pine stands in northern Spain and Mediterranean Maritime pine stands in Central Spain) were explored. Whole-stand yield, growth models and individual tree equations were used to estimate carbon stock in forests under different silvicultural alternatives and site indexes. Each alternative was evaluated on the basis of the land expectation value (LEV). Results reveal the appropriateness of implementing carbon payments, because it can clearly complement traditional management objectives in economic terms. Longer rotations on the poorest sites result in a positive economic return by introducing carbon output. The proportion of carbon stock in the final harvest relative to total fixed carbon is always higher in long rotation scenarios. However, short rotation systems produce the highest values of carbon MAI regardless of site index. The impact of carbon price is higher on the Maritime pine stands than on Scots pine stands. For both the species, changes in the discount rate have a minor impact on Carbon LEV. Notwithstanding, the proportion of total LEV due to carbon is greater when the discount rate increases.  相似文献   

19.
We explored environmental and genetic factors affecting seasonal dynamics of starch and soluble nonstructural carbohydrates in needle and twig cohorts and roots of Scots pine (Pinus sylvestris L.) trees of six populations originating between 49 degrees and 60 degrees N, and grown under common garden conditions in western Poland. Trees of each population were sampled once or twice per month over a 3-year period from age 15 to 17 years. Based on similarity in starch concentration patterns in needles, two distinct groups of populations were identified; one comprised northern populations from Sweden and Russia (59-60 degrees N), and another comprised central European populations from Latvia, Poland, Germany and France (49-56 degrees N). Needle starch concentrations of northern populations started to decline in late spring and reached minimum values earlier than those of central populations. For all populations, starch accumulation in spring started when minimum air temperature permanently exceeded 0 degrees C. Starch accumulation peaked before bud break and was highest in 1-year-old needles, averaging 9-13% of dry mass. Soluble carbohydrate concentrations were lowest in spring and summer and highest in autumn and winter. There were no differences among populations in seasonal pattern of soluble carbohydrate concentrations. Averaged across all populations, needle soluble carbohydrate concentrations increased from about 4% of needle dry mass in developing current-year needles, to about 9% in 1- and 2-year-old needles. Root carbohydrate concentration exhibited a bimodal pattern with peaks in spring and autumn. Northern populations had higher concentrations of fine-root starch in spring and autumn than central populations. Late-summer carbohydrate accumulation in roots started only after depletion of starch in needles and woody shoots. We conclude that Scots pine carbohydrate dynamics depend partially on inherited properties that are probably related to phenology of root and shoot growth.  相似文献   

20.
The superoxide dismutase (SOD EC 1.15.1.1) activity in Scots pine (Pinus sylvestris) and Norway spruce (Picea abies L. Karst.) needles in urban and rural trees of northern Finnish populations was studied. Enzyme activity was higher in pine than in spruce needles. Two pine clones from eastern Finland and Lapland revealed great differences in specific SOD enzyme activity.  相似文献   

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