Seasonal fluctuations of low‐molecular‐weight sugars,starch and nitrogen in sapwood of Pinus sylvestris L.

The content of water‐soluble substances and starch in the living tree stem at the time of felling influences wood durability during further utilization. The aim of the study was to describe the annual and seasonal fluctuations in the contents of stored carbohydrates and nitrogenous compounds. The contents of soluble sugars, starch, and nitrogen were measured in the outer sapwood (0–15 mm from cambium) of 65‐yr‐old Scots pine {Pinus sylvestris L.) trees during an annual cycle. To study the influence of growth conditions, samples were taken from different stands in Sweden, in one stand from a control and a fertilized block. The effect of the age of the trees on the content of stored substances was also considered by comparing young (10–15 yrs old) and older trees (40–65 yrs old). Determination of the carbohydrates was carried out using enzymatic analysis. The outer pine sapwood contained a higher content of low‐molecular weight sugars during autumn and winter than during spring and summer. Starch content rose at the beginning of the growth period and decreased in autumn. The content of soluble sugars increased towards the cambium on all sampling occasions. Fructose and glucose were dominant sugars in all the stands studied. Seasonal changes of sucrose were different from those of glucose and fructose, in that the sucrose content was already decreasing in February. The variations in the nitrogen content of the sapwood were far smaller than those of the soluble sugars. No significant differences were found between the stands with regard to glucose, fructose and the sum of all three sugars. The fertilized block showed low content of sucrose and nitrogen. It is concluded that seasonal fluctuations are more important with regard to the sugar content than the effect of growth conditions. Data indicate a lower content of soluble sugars and nitrogen in the outermost sapwood of young trees as compared with older trees.     

Irradiance in young stands of picea abies (L.) karst. and pinus sylvestris L. and the possibilities to prevent suckers of broad‐leaved trees

Incoming shortwave global radiation (Q _g) and photosynthetically active radiation (PAR; Q _pa as a fraction of full daylight, relative irradiance (%Q), were measured at the same time in young stands of Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.). Measurements were made on three levels above ground: 20 cm above ground and 50 and 15 % of stand height. Stands of three heights (75, 150 and 300 cm) were studied during two months. The stands were created by arranging young trees cut from natural stands, in nine quadratic spacings: 0.1, 0.2, 0.3, 0.4, 0.5, 0.7, 1.0, 1.4 and 2.0 m. The leaf area index (L) was estimated. Differences in %Q‐values for Q _pa and Q_g in the same species and at the same stand height and level of light measurements above ground were significant only in 150 and 300 cm stands. In 75 cm high stands of Scots pine, the %Q was <60% at spacings <0.2 m and in 75 cm high stands of Norway spruce, the %Q was <60% at spacings <0.3 m. Only at 0.1x0.1–0.3x0.3 m, %Q was <20% in Norway spruce stands. In 150 cm stands %Q<20% was measured at spacings <0.7 m in Norway spruce and <0.5 in Scots pine. In 300 cm stands of Norway spruce it was measured up to 1.2 and in Scots pine <1.1 m. Light extinction coefficients, K and K_g for spruce and pine stands were 0.17–0.40 and 0.16–0.31 respectively. Some practical implications of the study are presented. Lack of light (%Q<10%) as a single factor of seriously suppressed growth and development of broad‐leaved plants and suckers by competition in young stands of spruce and pine only occur in dense stands 0.3x0.3 m‐1.1xl.l m (8000–100000 stems/hectare). Competition by light on a regenerated area generally occurs in the level of 50% of tree height (150–300 cm) and higher due to the rapid growth of broad‐leaved trees (sprouts) compared with planted conifers but the light intensity at these levels %Q>10%.     

Long‐term effects of temperature on the wood production of Pinus sylvestris L. and Picea abies (L.) Karst. In old provenance experiments

Old provenance experiments with Scots pine and Norway spruce in Finland were used for assessing the long‐term effects of the projected climatic change on forest trees. The northernmost origins showed an increase in wood production when transferred southwards into a climate with an annual mean effective temperature sum close to that which is expected in northern areas as a result of the projected climatic change. A model is constructed with the estimated changes in wood production as a function of the annual mean temperature sum at the original location and the change in the annual mean temperature sum caused by the geographical transfer. The major changes in wood production are expected to occur in the northernmost areas of tree growth.     

Occurrence and berry production of Rubus chamaemorus L., Vaccinium oxycoccus L. & Vaccinium microcarpum Turcz. and Vaccinium vitis‐idaea L. on Swedish peatlands

During three consecutive years, 1978–1980, cloudberries (Rubus chamaemorus L.), cranberries (Vaccinium oxycoccus L. & Vaccinium microcarpum Turcz.) and lingonberries Vaccinium vitis‐idaea L.) growing wild in Swedish forests and mires were inventoried in the annual National Forest Survey. Both the coverage and fertility of these were estimated. Observations from 42 000 test sites (314 m² each) were processed according to geographical region, composition of tree and field layer, altitude and occurrence of draining ditches. Cloudberries cover 425 000 hectares or 1.5 % of the total investigated area (28.6 million hectares). The corresponding values for cranberries and lingonberries are 136000 hectares (0.5 %) and 1362000 ha (4.8%) respectively. Open mires have a greater degree of coverage by cloudberry and cranberry than wet forests on peat. The reverse situation is true for lingonberry. The total berry yield on peatland was estimated to 116.6 million kg (freshweight), distributed as 75.7 million kg cloudberries, 20.8 million kg cranberries and 20.1 million kg lingonberries. The corresponding production of lingonberries on mineral soils was 188.8 million kg. Both in wet forests and on mires, drained areas show lower berry production for the three species, with one exception. Lingonberries yielded better on drained mires. Productive stands of cloudberries and cranberries ought not to be drained for economic reasons.     

Effect of maternal soil treatment on first year growth and autumn frost hardiness of Pinus sylvestris L. full‐sib families

After‐effects of maternal soil treatment, controlling for photoperiod and weather conditions, were tested in a nursery experiment with Pinus sylvestris L. seedlings. Three full‐sib crosses were replicated in 4 different soil treatment plots of a grafted experimental seed orchard (63"54'N). Weight of filled seeds, percentage of empty seeds, first year hypocotyl and epicotyl length, and autumn frost hardiness (from artificial freeze testing) were evaluated. Systematic effects from maternal soil treatment were small compared to family differences for all characters studied. However, epicotyl length of the progenies showed a positive relationship with N needle content of the mother grafts. The results also indicated an important interaction between maternal soil treatment and autumn frost hardiness of the families. It is suggested that the altered mother tree treatment could lead to a change in progeny performance, corresponding to a 1.5 degree difference in latitudinal origin of natural stand seedlings. The results demonstrate the advantages of providing the mother tree with uniform conditions in early progeny testing.     

Genetic parameters of greenhouse growth and performance of 2‐year pinus contorts subsp. latifolia

Stand differentiation, heritabilities and genetic correlations in 16 growth, bud and branch traits in Pinus contorta subsp. latifolia were 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, h² varied 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 of P. contorta subsp. latifolia.     

The impact of climate change on fire risk in Daxing’anling,China

Daxing'anling is a key region for forest fire prevention in China.Assessing changes in fire risk in the future under multiple climatic scenarios will contribute to our understanding of the influences of climate change for the region and provide a reference for applying adaptive measures for fire management.This study analyzed the changes in fire weather indices and the fire season under four climate scenarios(RCP2.6,RCP4.5,RCP6.0,RCP8.5)for 2021–2050 using data from five global climate models together with observation data.The results showed that the analog data could project the average state of the climate for a given period but were not effective for simulating extreme weather conditions.Compared with the baseline period(1971–2000),the period 2021–2050 was predicted to have an increase in average temperature of 2.02–2.65 °C and in annual precipitation 25.4–40.3 mm,while the fire weather index(FWI) was predicted to increase by6.2–11.2% and seasonal severity rating(SSR) by5.5–17.2%.The DMC(Duff moisture code),ISI(initial spread index),BUI(build-up index),FWI and SSR were predicted to increase significantly under scenarios RCP4.5,RCP6.0,and RCP8.5.Furthermore,days with high or higher fire danger rating were predicted to be prolonged by 3–6 days,with the change in the southern region being greater under scenarios RCP4.5,RCP6.0,and RCP8.5.     

Light quality and intensity of light-emitting diodes during pre-cultivation of Picea abies (L.) Karst. and Pinus sylvestris L. seedlings – impact on growth performance,seedling quality and energy consumption

Three different LED lamps with continuous spectra were compared against commonly used fluorescent lights. The lamps were characterized by light output, energy consumption and spectral quality for plant growth. The biological effects of light quality were compared by pre-cultivating seedlings of Picea abies (L.) Karst. and Pinus sylvestris L. under each spectrum for 35 days in a growth chamber with controlled temperature, humidity and photoperiod. The seedlings were then transplanted and cultivated for one vegetation period at the nursery, then planted outdoors on a forest field trial and followed for three years. The seedlings showed similar growth performance for all spectra tested. LED lamps have several advantages to fluorescent light such as energy consumption, longer life span and adjustable light intensity. Regarding light intensity the effects on growth performance were studied for both species using the most promising LED spectra. The photosynthetically active radiation (PAR) was maintained at 50, 100, 200 and 400 μmol?m^?2?s^?1. Unlike energy consumption, seedling development did not display a linear relationship to light intensity. Instead, the results show an optimum light level between 100 and 200?μmol?m^?2?s^?1 for the shade tolerant Picea abies seedlings and a level of around 200?μmol?m^?2?s^?1 for the more shade intolerant Pinus sylvestris seedlings.     

Growth loss and economic consequences following two years defoliation of pinus sylvestris by the pine sawfly neodiprion sertifer in West‐Norway

Two years of heavy defoliation of Pinus sylvestris by Neodiprion sertifer caused a volume loss of 33 % during a 9‐year period after the defoliation of 90–120 years old pine forests. This loss corresponds to 3 normal annual increments. The increment losses in height, diameter and basal area are calculated both for the old stands and a young one (40 years of age). The economic consequences of the growth loss are also calculated and discussed.     

A preliminary study on the genetic structure of Northern European pinus sylvestris L. by means of neutral nuclear microsatellite markers

This paper aimed to investigate the genetic structure (GS) of Scots pine in the northern area of its distribution range by means of seven neutral nuclear microsatellite markers. In particular, the postglacial recolonization of these areas and possible different adaptation patterns in distinct refugia were studied. The GS and diversity were assessed with seven pairs of neutral nuclear microsatellite primers. A high genetic diversity was found in the Scots pine material tested, along with a shallow GS. This pattern is typical for recolonized areas and species with large population sizes, which are connected by pollen-mediated gene flow. A STRUCTURE analysis found two genetic groups to be the most likely, one south-eastern and one north-western group that meet in Fennoscandia. This indicates that Scots pine recolonization of Fennoscandia might have taken place from two different directions (south-west and north-east). Scots pine that recolonized the area originated in at least two different refugia during the last glacial maximum. The glacial survival in distinct refugia can have led to different adaptation patterns and growth optima in the different groups as reflected in the formation of latewood content, where lineage was a significant influencing factor.     

Stand and site characteristics in the decline of pinus sylvestris caused by gremmeniella abietina shoot disease in a severely damaged 50‐year‐old plantation in se lapland

The role of stand and site characteristics in a 50‐year‐old, sowed Scots pine (Pinus sylvestris L.) stand on the decline of Scots pine caused by Gremmeniella abietina was studied. Treewise damage of Scots pine was modelled using stand and site variables and stepwise regression analysis. The significant variables included in the model were stand elevation from the main cold air centre and the pH of the humus layer, while the other less significant variables were the number of stems per hectare of Scots pine and Norway spruce, content of Cu and Ni in the humus layer, and the thickness of the humus layer and the A₂ horizon. The studied variables excluded from the model were the number of broad‐leaved trees per hectare, Al and Pb contents in the humus layer, and Al, Cu, Pb and Ni contents in the A₂ horizon. The results strongly suggest that the vicinity of water as well as local depressions act as vulnerable sites for Scots pine and the said vulnerability is enhanced by increased pH of the humus layer.     

Freezing temperatures in the root zone—effects on growth of containerized Pinus sylvestris and Picea abies seedlings

Roots of 1‐year‐old containerized seedlings of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) were experimentally frozen in December. The seedlings were then grown for 3 weeks in a growth chamber and evaluated with regard to root growth capacity (RGC) and shoot elongation. The subsequent RGC of Scots pine declined as root zone temperatures were lowered from ‐6°C to ‐11°C and from ‐11°C to ‐16°C. Almost no root growth was observed after exposure to ‐20°C. Shoot growth was also negatively affected by low root temperatures but less than root growth. Low root temperatures did not affect Norway spruce as much as Scots pine, although root and shoot growth of Norway spruce were reduced after exposure to the lowest test temperatures (‐16°C and ‐20°C). The length of exposure, ranging between 1 and 8 hours had no effect on subsequent growth.     

Long‐term effects of liming on the fine‐root standing crop of Picea abies and Pinus sylvestris in relation to chemical changes in the soil

The long‐term effects of lime application on fine roots of Norway spruce, Picea abies (L.) Karst, and Scots pine, Pinus sylvestris (L.), have been studied in five experimental forest stands subjected to different lime applications 5 to 18 years before the present study was undertaken. The effects of liming does not seem to significantly influence fine‐root development in forest stands in the long term. The only response to liming in measured root variables was a tendency to increased specific root length (SRL = fine‐root length/fine‐root dry weight, m/g). A correlation between increased SRL, decreased root biomass and increased stem volume growth was indicated. Changes in water extractable amounts of mineral elements—P, K, Ca, Mg, Mn, S, Al and Fe‐in bulk soil and rhizosphere soil from the mineral soil layers were studied in a control area and an area treated with 3830 kg CaCO₃ ha^‐1. Few significant differences were found between treatments, and then mainly in the case of Ca.     

The impact of Pinus halepensis afforestation on Mediterranean spontaneous vegetation: do soil treatment and canopy cover matter?

We investigated central Mediterranean Pinus halepensis plantations under semi-arid climate in order to evaluate the combined effect of soil treatment and afforestation practices on spontaneous plant species composition,richness and evenness,and on the trend and speed of vegetation dynamics.Phytosociological relevés of three different plot typologies,i.e.(1) soil-treatment and plantation,(2) only soil-treatment,(3) no soil-treatment and no plantation,were compared by(a) multivariate analysis and(b) with reference to species richness and evenness.Moreover,in order to compare vegetation dynamics within the plantations with those ones ongoing in semi-natural garrigue communities,we compared life form and syntaxonomic spectra between phytosociological relevés taken at 8 years of distance.DCA showed that floristic species composition and similarity are influenced by the canopy cover of Pine trees as well as by soil-treatment practices.Although species richness and evenness are not clearly related to neither soil treatment nor Pine afforestation,canopy cover clearly plays a major role:in fact,the highest Ph cover rates correspond to the lowest values of understory species richness.This is true also if only species of biogeographical/conservation interest are considered.Regarding vegetation dynamics,sites with dense Pine canopy cover evolve much slower than the adjacent garrigue communities.The same factors invoqued to explain the patterns of floristic composition and similarity(i.e.allelopathy and competition for light,water and nutrients) may also explain the lowering of diversity of therophytes and the strong decline of the cover perfomed by both therophytes and hemicryptophytes underneath the canopy of dense Ph plantations.Thus,in sites where Ph cover exceeds about 80%,thinning is recommended not only in order to accelerate succession,but also to give a natural ’shape’ to afforestations.     

Survival and long-term growth of eucalypts on semi-arid sites in a Mediterranean climate,South Africa§

Four experiments were established on the semi-arid west coast plain of South Africa during the 1990s. The trails tested the survival and growth of several eucalypt species and hybrids, some of which were established in a climate that is drier than their natural distribution range. The aridity indices (AI; defined as mean annual precipitation [MAP]/mean annual potential evapotranspiration) ranged from 0.21 to 0.36 and MAP from 228 to 423 mm. The driest trial site (AI = 0.21 and MAP = 228) had high levels of mortality. However, a number of species (in particular, Eucalyptus gomphocephala, E. camaldulensis and E. tereticornis, as well as individual hybrids of the latter two species with E. grandis) survived and grew well at the remaining sites. Eucalyptus cladocalyx survived well and attained competitive growth rates only on the wettest site in the group (AI = 0.36). The dominant height of the top-performing genotypes at age 5 ranged between 9 and 10 m on the two wetter sites. This corresponded to mean annual increment values in excess of 10 m³ ha^?1 a^?1, which is comparable to volume obtained at more favourable aridity indices in the summer rainfall zone of South Africa and exceeds the growth rates obtained in several other arid zone studies globally. The E. grandis × E. camaldulensis hybrid ranked among the top performers in two trials, but its susceptibility to recently introduced pests and relatively poor wood quality makes it a less attractive choice for planting. The high density and durability of timber, acceptable growth rate (given the low rainfall conditions), and low pest and disease incidence make E. gomphocephala and E. cladocalyx the species of choice for planting in the drier and relatively wetter sections of the semi-arid zone, respectively.     

The production and use of knowledge in regulatory impact assessment – An empirical analysis

Regulatory Impact Assessment (RIA) – understood as the formalised analytical activities initiated or carried out by central government administrations when designing specific policy instruments – is currently receiving high levels of political attention. It is seen as a tool to improve regulatory quality and to promote cross-cutting objectives such as sustainable development. Often conceived as an economic analysis of costs and benefits, RIA tends to be depicted as a ‘neutral’ assessment process that informs decision-makers about ‘facts’. This does not explain, of course, why RIA often becomes an arena for political conflict involving both government departments and stakeholders. Based on empirical research on the design and practical application of RIA across the European Union, this paper explores the relationship between RIA, policy-making and politics. The aim is to shed light on what knowledge is produced, how it is used by different actors and what role it plays in decision-making. Based on this analysis, we explore to what extent and under what conditions RIA can serve as a tool for more evidence-based and sustainability oriented policy-making processes.     

The impact of climate change on forest fire danger rating in China’s boreal forest

The Great Xing’an Mountains boreal forests were focused on in the northeastern China.The simulated future climate scenarios of IPCC SRES A2a and B2a for both the baseline period of 1961-1990 and the future scenario periods were downscaled by the Delta Method and the Weather Generator to produce daily weather data.After the verification with local weather and fire data,the Canadian Forest Fire Weather Index System was used to assess the forest fire weather situation under climate change in the study region.An increasing trend of fire weather severity was found over the 21st century in the study region under the both future climate change scenarios,compared to the 1961-1990 baseline period.The annual mean/maximum fire weather index was predicted to rise continuously during 2010-2099,and by the end of the 21st century it is predicted to rise by 22%-52% across much of China’s boreal forest.The significant increases were predicted in the spring from of April to June and in the summer from July to August.In the summer,the fire weather index was predicted to be higher than the current index by as much as 148% by the end of the 21st century.Under the scenarios of SRES A2a and B2a,both the chance of extremely high fire danger occurrence and the number of days of extremely high fire danger occurrence was predicted to increase in the study region.It is anticipated that the number of extremely high fire danger days would increase from 44 days in 1980s to 53-75 days by the end of the 21st century.     

Effects of different culture media on the growth of Indian sandalwood （Santalum album L.） seedlings in Zhanjiang, Guangdong, southern China

We studied the effects of different culture media on the growth of India sandalwood(Santalum album L.) seedlings in Zhanjiang,Guangdong Province in southern China. Five different growth substrates,lateritic subsoil,burnt soil,agricultural soil,peaty soil and coconut dust,were used as the basic culture materials and seven different treatments of composition were used as potting media. Kuhnia rosmarinifolia Vent. was used as a primary host plant for all treatments. Statistically significant differences were f...     

Below‐Canopy distribution of photosynthetically active radiation and its relation to seedling growth in a boreal Pinus sylvestris stand

A simulation model was used to predict the spatial distribution of direct and diffuse photosynthetically active radiation below a heterogenous canopy of a Pinus sylvestris stand in eastern Finland. Seedling growth was related to both measured and predicted radiation. The model predicted rather well the overall pattern of radiation distribution beneath the canopy. All the growth parameters of Pinus sylvestris seedlings (height, current height increment and mean height increment) correlated positively with the amount of both measured and predicted radiation. The correlation between seedling growth and irradiance was better for predicted diffuse radiation than for total radiation. This was probably because diffuse radiation, being symmetrically distributed around trees, correlates more strongly than direct radiation with other factors affecting seedling growth.     

Effect of resin‐top disease caused by Peridermium pini on the volume and value of Pinus sylvestris saw timber and pulpwood

The role of the resin‐top disease caused by Peridermium pini in volume and value losses to Scots pine (Pinus sylvestris L.) was surveyed in two heavily infected stands in northern Finland. Of the Scots pines, 26% were infected by the disease. Peridermium pini caused 2% volume losses to saw timber trees and 3% volume losses to pulpwood trees in the stem‐lesion class and 10% and 14% in the dead‐top class, respectively. The disease caused saw timber volume losses to saw timber trees of 34% and 22% in the stem‐lesion and dead‐top class, respectively. However, saw timber volume losses increased the pulpwood volume in both disease classes. The disease reduced the marketing value of saw timber trees and pulpwood trees by 18% and 3% in the stem‐lesion class and by 15% and 14% in the dead‐top class.