Growth Of Scots Pine Research Articles

The influence of initial spacing on growth and survival of Scots pine in 40 years period of cultivation in varied habitat conditions

Abstract The aim of the research was to determine the effect of initial spacing on the survival and growth of pine trees in dry coniferous and fresh coniferous forest habitats after nearly 40 years from the establishment of plantation. The study presents an analysis of seven spacing variants in square, rectangular and triangular spacing patterns with the initial density ranging from 6 944 seedlings/ha to 15 625 seedlings/ha. The studies were conducted on two study sites. No tending treatments (selective thinning) were performed in the examined stands throughout the growing season. It was shown that habitat conditions had a significant effect on the survival, diameter and height growth of trees in pine stands. In the less productive forest habitat, where the competition of trees is smaller, the survival was 1.5 to 2-fold higher compared to the more productive habitat. Pine trees growing in the fresh coniferous forest had substantially larger diameters at breast height (dbh) compared to the dry coniferous forest. The spacing effect depended on the habitat conditions. This influence was stronger in the less productive habitat compared to the more productive forest habitat which was reflected in the greater differences in the discussed parameters. The average dbh value of all trees on the Płock site increased with the increase of tree growing space (i.e. lower initial planting density) and ranged from 8.24 cm in variant A (15 625 seedlings/ha) to 9.79 cm in variant C (6 944 seedlings/ha). On the Łąck site, the trees growing at a low density (variants C and E) had significantly larger diameters compared to the trees growing at a density from 10 000 plants/ha to 15 625 plants/ha (spacing variants A, B, F, G). The studies also showed a significant effect of the habitat conditions and initial spacing on the diameter of pine trees in biosocial class I. Triangular spacing in the fresh coniferous forest was found to have more positive effect on tree diameter growth. It is consistent with the findings of other authors that trees planted in triangular spacing make better use of space which is positively reflected in their growth. The results obtained from the research allow to formulate the conclusion that habitat conditions have a significant effect on the survival, diameter and height growth of trees in pine stands. The research also showed a significant effect of initial spacing on the diameter at breast height of pines at the end of age class II. No dependence was found of the initial planting density on the height growth rate of trees. In both forest habitats under consideration, trees planted at a density of approximately 11.5 thousand plants per hectare were the highest. The triangular initial spacing pattern had a positive effect on this characteristic.

Wood ash in boreal, low-productive pine stands on upland and peatland sites: Long-term effects on stand growth and soil properties

The effect of wood ash on growth of Scots pine was studied in 64- to 75-year-old stands on three upland sites (Exps. 402, 407 and 408) for 20years and in a 30-year-old Scots pine stand on an oligotrophic peatland site (Exp. 251) for 25years. In Experiments 407 and 251 the responses of soil chemical properties and soil microbiological processes related to C and N cycling were also studied. The upland experiments included a control and a treatment with 3Mgha−1 of wood ash. In Exp. 407, 120kg Nha−1 was applied together with ash; this experiment also included a treatment with N alone. The peatland experiment included a control and a treatment with 4.8Mgha−1 of wood ash. All experiments had 3 replications. Wood ash significantly decreased soil acidity on all sites. On the upland site, after 20years, the concentration of K2SO4-extractable DOC and the rates of C mineralization (CO2–C production) and net N mineralization were all higher in the Ash+N treatment than in the control or N treatments. However, the treatments did not significantly affect the amounts of C or N in the microbial biomass or the concentration of NH4–N. On the peatland site, after 27years, ash stimulated C mineralization and cellulose decomposition, but microbial biomass C or N, net N mineralization or the concentration of N were not affected significantly. On both the upland and peatland site, net nitrification was very low in all treatments. In Exp. 408, the volume growth in the control and Ash treatment was during the 20-year study period 60 and 64 m3ha−1, respectively, and in Exp. 402 108 and 120m3ha−1, respectively, the latter difference being significant. In Exp. 407, the volume growth in the Ash+N treatment was during the 20-year study period significantly higher (92m3ha−1) than in the N and control treatments (76 and 73m3ha−1, respectively). On the peatland site during the 25-year study period the growth was 145 and 169m3ha−1, in the control and Ash treatments, respectively. In conclusion, the long-term positive response of stem growth to wood ash on peatlands and N fertilized upland sites can be partly explained by changes in soil nutrient status and by microbial processes related to C and N cycling.

Six Temperature Proxies of Scots Pine from the Interior of Northern Fennoscandia Combined in Three Frequency Ranges

Six chronologies based on the growth of Scots pine from the inland of northern Fennoscandia were built to separately enhance low, medium, and higher frequencies in growth variability in 1000–2002. Several periodicities of growth were found in common in these data. Five of the low-frequency series have a significant oscillatory mode at 200–250 years of cycle length. Most series also have strong multidecadal scale variability and significant peaks at 33, 67, or 83–125 years. Reconstruction models for mean July and June–August as well as three longer period temperatures were built and compared using stringent verification statistics. We describe main differences in model performance (R2 = 0.53–0.62) between individual proxies as well as their various averages depending on provenance and proxy type, length of target period, and frequency range. A separate medium-frequency chronology (a proxy for June–August temperatures) is presented, which is closely similar in amplitude and duration to the last two cycles of the Atlantic multidecadal oscillation (AMO). The good synchrony between these two series is only hampered by a 10-year difference in timing. Recognizing a strong medium-frequency component in Fennoscandian climate proxies helps to explain part of the uncertainties in their 20th century trends.

Variation in reproduction and growth in declining Scots pine populations

Disentangling how variation in reproduction and growth is linked in plants across different ecological scales, and how allocation rules change in response to stress are fundamental aspects of life history theory. Although it is known that reproductive allocation is an allometric process and that environmental conditions can influence demographic traits, patterns of variation in vegetative and reproductive functions across and within individuals of tree species suffering drought-induced decline have rarely been documented. In this study we use Scots pine (Pinus sylvestris L.) as a model species to explore patterns of variation in cone production and growth in two declining populations at the southern edge of its distribution. A Bayesian approach was used to assess how these demographic traits vary as a function of drought effects and competition and covary across different ecological scales. The allometric trajectories relating tree size with cone production and growth differed along gradients of drought impacts and biotic interactions. Although reproduction and growth increased with tree size, cone production reached a maximum at intermediate sized trees and stabilized or decreased at larger sizes. Drought stress effects (defoliation at the tree level and overall decline at the plot level) and competition for resources reduced cone production and growth. Our results also showed differential effects of defoliation on cone production depending on tree size, with stronger effects on larger individuals. After accounting for these effects, much of the variation of demographic traits and correlations among them occurred at small ecological scales across individuals (i.e. within plots) and within individuals across years. This resulted in covariations between demographic traits among nearby individuals and within individuals through time, suggesting a consistent advantage in resource acquisition of some individuals within plots, and trade-offs between growth and cone production within trees across years. In conclusion, this study reports that drought-induced forest decline is associated with lower growth and cone production in Scots pine, which could contribute to explain the long-term impacts of drought in southern populations of this species and, in particular, its low regeneration capacity after severe drought.

High negative genetic correlations between growth traits and wood properties suggest incorporating multiple traits selection including economic weights for the future Scots pine breeding programs

The development of multiple trait selection indices for solid (structure) wood production in the Scots pine (Pinus sylvestris L.) breeding program requires genetic variances and covariances estimated among wood quality traits including stiffness. Genetic control and relationships among Scots pine growth, fiber, and wood quality traits were assessed by estimating heritability, phenotypic and genetic correlation using a Scots pine full-sib family trial. Wood quality traits including clearwood and dynamic acoustic stiffness were measured using SilviScan and Hitman in a 40-year-old progeny trial and by sampling increment cores of 778 trees of 120 families. Genetic parameters were estimated using the mixed model by the ASReml software. Heritability ranged from 0.147 to 0.306 for growth, earlywood, transition wood and latewood proportion traits and from 0.260 to 0.524 for fiber dimension, wood density, MFA and stiffness traits. The highly unfavorable genetic correlation between diameter and whole core density (−0.479) and clearwood stiffness (−0.506) and dynamic acoustic stiffness (−0.382) was observed in this study. The unfavorable genetic correlations between growth traits and stiffness indicate that multiple traits selection using optimal economic weights and optimal breeding strategies are recommended for the advanced Scots pine breeding program.

Growth patterns at the southern range edge of Scots pine: Disentangling the effects of drought and defoliation by the pine processionary caterpillar

Dendrochronology and climate-growth modelling were used to assess to what extent defoliation by pine processionary moth (Thaumetopoea pityocampa) depresses growth in Scots pine (Pinus sylvestris) at the species’ southernmost distribution limit (southern Spain). Basal area increment (BAI) was measured in severely defoliated and non-defoliated trees, for a period of 20years, a period that includes three severe droughts and two severe outbreaks of pine processionary moth. Linear mixed-effects models of BAI as a function of climate were run for non-defoliated trees and thereafter the fit of the model was tested separately both for defoliated and non-defoliated ones. Severely defoliated trees showed pronounced growth reductions during defoliation, although their cumulative basal area and drought-sensitivity were similar to those of non-defoliated trees. The results were not related to tree size or age, while non-climatic residuals were significantly related to the defoliation percentage. The combined effect of drought stress and processionary caterpillar defoliation caused short-term growth reduction in affected trees, although defoliated trees presented higher growth recovery after the defoliation, displaying similar average growth. We conclude that, in Scots pine, the growth reduction induced by processionary caterpillar defoliation can be overcome to a greater extent than the impact of drought.

Influence of substrate compaction in nursery containers on the growth of Scots pine (Pinus sylvestris L.) seedlings

Abstract The paper presents research on influence of nursery soil compaction, composed of peat (90%) and perlite (10%), on the growth of seedlings of Pinus sylvestris grown in containers. Polyethylene nursery are containers used for the seedling production. These containers were filled with three different densities of the peat and perlite substrate (0.3, 0.5 and 0.7 g·cm-3). During the experiment, nursery containers were initially placed in a plastic tent for a period of two months, and then for three months further months in an open nursery field. Growth measurements for individual plants were the length of shoots and the root system, root collar diameter, root and shoot dry weight and photosynthetic rate. There was a relationship between the extent of compaction of the soil substrate and all analyzed growth parameters of seedlings. A more compact substrate adversely affected on the number of grown seedlings and their length but positively influenced the dry mass of pine seedlings.

Mixtures with spruce species can be more productive than monocultures: evidence from the Gisburn experiment in Britain

In1955,anexperimentwasestablishedatGisburnforestinnorthernEnglandtocomparetheperformanceofpure and mixed plots of four species: Norway spruce (Picea abies), Scots pine (Pinus sylvestris), sessile oak (Quercus petraea)andcommonalder(Alnus glutinosa).Attheendofthefirstrotation,therewasenhancedgrowthinallmixtures with Scots pine while there was a negative interaction in the Norwayspruce/sessile oak mixture. The experiment wasfelled in 1989 after windblowand replanted in 1991, when Sitka spruce (Picea sitchensis) was added to the species trialled. After 20 years of the second rotation, patterns of individual species growth were generally similar to those in the first rotation, except that height and diameter growth of Norway spruce and Scots pine was significantly greater (P , 0.01) in mixed plots. Basal area growth of three combinations (Sitka spruce/Scots pine; Norway spruce/Scots pine; Norway spruce/common alder) was about 40 per cent greater than (and significantlydifferentfrom)thatpredictedfromperformanceinpureplotsofthesamespecies,evidenceoftransgressive overyielding. These results indicate that facilitation effects through improved nutrient status can lead to better productivity in mixed-species stands in planted forests. The implications of these findings for policies seeking to diversify single species planted forests are considered.

Long-term effects of stump harvesting on soil properties and tree growth in Scots pine and Norway spruce stands

Effects of stump harvesting on the properties of surface soil and on the density, structure and growth of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) stands were estimated in a field trial in western Finland. The experiment was established in 1977 and measured in 2010. Stems and logging residues were harvested after clear-cutting, and stumps were lifted and removed from half of the experimental area. Sixteen plots were planted with pine seedlings and 16 with spruce. The main effects of stump harvesting were improved survival of planted trees and an increase in natural regeneration. No clearly negative effects were noted in the stand development. Stump harvesting had no or minimal effects on the properties of the organic layer and those of the 0- to 10-cm mineral-soil layer. Soil properties did not differ between tree species. Pine production was higher on plots with stump removal compared to plots without soil treatment.

Dynamic response of tree growth to changing environmental pollution

Long-term investigations of Scots pine (Pinus sylvestris L.) growth were carried out in the vicinity of one of the biggest air pollution sources in Lithuania—mineral fertilizers plant “Achema.” It is detected that initial stages of the dynamic tree response to the external stress factors in the polluted environment with an increased quantity of nitrogen compounds have started with a stimulation stage, followed by a gradual transition to a depression of growth. The recovery of the damaged stands took place along with the reduced environmental pollution, and the overdraft of the “normal” annual increment was a characteristic feature of all the investigated stands. This phase is still continuing for the most damaged stands. A very high individual variability of the tree growth response to the environmental impact is a characteristic feature of the damaged Scots pine stands. The homeostatic mechanisms of the survived trees stipulated reaching approximately the same or even higher growth rate as prior to the depression period, and the tree growth rate before the depression period can serve as the most powerful predictor of tree growth recovery capacity under the reduced environmental pollution. Crown defoliation is the next most important predictor of individual tree recovery capacity. Lower stand density and lower competition cause higher recovery capacity of damaged trees. The conclusion is made that a reduction in the environmental pollution on the local and regional scale and especially a decrease in emissions and deposition of sulfur and nitrogen compounds caused the recovery of damaged forests. These trends should be taken into account while analyzing and modeling forest dynamics. Interaction of environmental pollution and climatic factors is very important for the response of tree growth to the environmental stressors.

Impact of climate and drought events on the growth of Scots pine (Pinus sylvestris L.) provenances

We explored the growth response of Scots pine to temperature, precipitation, and drought focusing on eleven provenances from the IUFRO 1982 international provenance trial. At two macroclimatically different sites in Germany we measured chronologies of tree-ring widths and annual height increment. We estimated general climate/growth relationships and examined the growth response, based on tolerance indices of resistance, recovery, resilience and relative resilience, to the most severe drought event per site. Using multivariate benchmarking of provenance archetypes, we established a ranking of the individual provenances in terms of general performance. In addition to considerable differences in overall growth between provenances, growth metrics differed between sites which were mostly attributable to climate. Basal area increment depended mainly on water availability from May to July, whereas annual height growth was influenced by moisture deficit during May of the current year.The reaction to drought events was shown to depend on the timing and duration of the drought event. Differences between provenances in resistance were modest, but more pronounced for recovery and especially for resilience and relative resilience. The results indicate a better adaptation to drought of the provenance from Bosnia Herzegovina and of local German provenances compared to other provenances. We summarized the findings by aligning the eleven provenances between two multivariately defined archetypes, one of which represented best general performance defined by good overall growth, low climate sensitivity and high resilience to drought. This approach confirmed the superior performance of the local German populations. Provenances from France and Poland were ranked above average whereas northern provenances and that from Bosnia Herzegovina were found to be least suitable at the sites under investigation. Our results clearly demonstrate the importance of considering provenance in the discussion about future adaptedness and adaptability of tree species under climate change scenarios.

Effect of climatic factors on height increment of Scots pine in experimental plantation in Kalsnava, Latvia

Effects of climatic factors on tree growth are usually determined by analysis of various tree-ring parameters thus focusing on secondary growth. Relationships between climatic factors and height (primary) growth of trees, which is important parameter in forestry and has been linked with geography of species, is poorly studied, mainly due to laborious gathering of data. However, several studies dealing with height growth of Scots pine in Finland showed that climatic factors have a strong effect on height growth. Thus height increment of trees also appears as a valuable proxy for climatological studies.Relationships between height growth of Scots pine in two experimental plantations (local provenance and diallel hybridization experiment) in eastern part of Latvia and climatic factors was determined by dendrochronological techniques. Similarity of high frequency variation of annual height increment (HI) between trees in each plantation was determined by PCA. Effects of climatic factors were determined by correlation analysis. For each plantation two groups of trees were distinguished. These groups showed slight differences in high-frequency variation HI. Height growth of trees from diallel hybridization experiment was sensitive to temperature in early spring and precipitation in dormant period; however, differences in significant climatic factors were observed between groups. Groups distinguished for local provenance experiment differed by mean HI. Both groups showed sensitivity to temperature in May and precipitation in previous July and September; however, fast growing trees showed higher correlation coefficients and additional sensitivity to summer and seasonal amounts of precipitation. As the distinguished groups consisting of trees from different origin or with hybridization patterns, thus the differences in height-growth-climate relationships apparently might be related with individuality of tree growth or different functional traits of trees.

Growth of Scots pine (Pinus sylvestris L.) on forest and former agricultural lands in Krynki Forest District

Growth of Scots pine (Pinus sylvestris L.) on forest and former agricultural lands in Krynki Forest District

Regional climatic signals in Scots pine growth with insights into snow and soil associations

We performedclimatic assessments of Scots pine growth variations in Finlandover recent decades by their tree-ring series andcomparing growth variations to those observedin meteorological record s. Tree-ring indices showed non-significant growth trends over roughly the past four decades (1972-2007). The observedgrowth variability was explainedby connexions to the mid -summer (July) climate (temperature and, likely, cloudiness) in the north and to the spring (April) soil temperatures in the south. Tree growth was negatively associated with snow depth at the beginning of dormancy (in November, previous to the corre- sponding growth year) in the south and during the growing season start (May) in the north. Thus, these anal- yses emphasized the relevance of snow and soil data, which have usually been overlooked in studies of associ- ations between climate and tree-ring changes.

Drought and mistletoe reduce growth and water-use efficiency of Scots pine

To what extent do mistletoes contribute to growth decline in drought-prone forests? Can the rising atmospheric CO2 concentrations offset the negative impacts of drought and mistletoe infestation on tree growth? Long-term data on growth and intrinsic water use efficiency (iWUE) may allow answering both questions. We used dendrochronology to assess long-term changes in radial growth and iWUE in Scots pine (Pinus sylvestris) trees severely infested by mistletoe (Viscum album) as compared to non-infested trees. The relationships among tree variables and mistletoe infestation were quantified using structural equation models. Linear mixed-effects models of basal area increment as a function of climate were fitted to severely infested and non-infested trees. Infested trees showed higher stem and crown diameters because they grew faster than non-infested trees in the past. Mistletoe infestation enhanced defoliation and reduced radial growth for more than 10years prior to sampling, while iWUE was significantly lower on severely infested trees only for the last 5years. Severely infested trees had higher growth responsiveness to drought stress than non-infested trees. Although infested and non-infested trees displayed similar rising iWUE temporal trends, the combined effect of drought stress and mistletoe infestation caused a reduction in growth and reversed the CO2-induced increase of iWUE in infested trees. We conclude that rising atmospheric CO2 concentrations cannot compensate for the impacts of drought and mistletoe on tree growth and iWUE.

Effects of stabilized wood ash on nutrient status and growth of Scots pine – Comparison between uplands and peatlands

The effects of granulated and self-hardened wood ash on the nutrient status and stem growth of middle-aged Scots pine (Pinus sylvestris L.) stands were studied at two upland and two peatland sites 13years after ash application. The study sites were located in central Finland and represented different site fertility classes. The treatments consisted of an unfertilized control and two different doses of ash, 3 and 9Mgha−1 (upland sites) or 5 and 15Mgha−1 (peatland sites) on fresh weight basis, with both types of wood ash. All four sites had a similar experimental design following the principles of randomized blocks with four replications.The effect of ash treatments on the stand growth depended on the site type and ash dose. At the nutrient-poor upland site, the ash-induced response in the basal area growth was slightly positive and at the more fertile site slightly negative. However, in all cases the growth response at the upland sites was non-significant. At peatland sites, the ash applications increased stand growth remarkably, and the ash-induced basal area response strengthened with time, especially at the more fertile site. The high application rates resulted in stronger responses than the lower doses at the peatland sites. At the end of the study period, the annual basal area increment on the plots treated with the higher application rate of ash was 1.7–1.8-fold at the nutrient-poor site and 4–5-fold at the more fertile site compared with the control.While the trees in unfertilized control plots of peatland sites had sufficient (Site 3) or even an abundance of (Site 4) available N, they were suffering from severe P and K deficiencies (Site 4) or moderate K deficiency (Site 3). Higher dose of both ash types increased needle K concentrations at both peatland sites and that of P at Site 4 above the deficiency limit. At upland sites no nutrient deficiencies were found. All ash treatments increased needle B concentrations both at upland and peatland sites.

Effect of mineral composition and medium pH on Scots pine tolerance to toxic effect of zinc ions

Effect of mineral composition and pH of nutrient medium on the growth of Scots pine (Pinus sylvestris L.) seedlings and their tolerance to toxic effect of zinc ions was investigated by modifying the standard Knop-Hoagland medium (pH 6.6) (M1). The improved medium (M2) was more acid (pH 4.5) and notable for 2.7-fold lower osmolarity, with equimolar ratio between ammonia and nitrate nitrogen, assimilable form of iron (9 μM Fe2+), and the presence of 0.02 μM Co2+ and 2 mM Cl−. Owing to balanced mineral composition and low pH, M2 enhanced seedling growth under normal conditions and reduced the toxic effect of 100 μM ZnSO4. Rapid development of the root system (main root, the number and total length of lateral roots) on M2 was maintained even under stress conditions (100 μM Zn2+); as a result, the ratio between the biomass of aboveground organs and the biomass of the root system remained on the level of 2.5, whereas on M1, it increased to 3.9. At the same time, on M2 we observed accelerated production of the needles with elevated content of photosynthetic pigments therein. Investigation of the operation of individual components of antioxidant system (superoxide dismutase, catalase, ascorbate peroxidase, and guaiacol peroxidases) and peculiarities of proline accumulation showed that Scots pine seedlings grown on M2 experienced less oxidative stress than the seedlings grown on M1. The probable physiological foundation of the observed phenomena is discussed.

Ecotypic variation in response to light spectra in Scots pine (Pinus sylvestris L.)

We investigated Scots pine adaptive responses to the light spectra by measuring hypocotyl length in seeds sampled from three natural Scots pine ecotypes across a latitudinal cline ranging from 63° to 68° N in Sweden where the adaptive cline is known to be steeper. Seeds were germinated under dark (D) and three monochromatic continuous light wavelengths: blue (B), red (R) and far-red (FR). Analysis of variance revealed a northward decrease in the inhibitory effect of FR with respect to D, the so-called far red high irradiance response. Ecotypic variation for hypocotyl development was observed under the FR and D treatments, while the trends for the B and R treatments were not statistically significant. Under FR the ecotypic variation showed an increase in hypocotyl length northwards, in contrast to the treatment under D which showed a decrease in the hypocotyl length northwards. These results could be interpreted in view of the previously reported northward increase in FR requirement to maintain growth in Norway spruce and Scots pine. Prior to the performance of the main light experiment, the maternal effect on progeny performance was investigated, which showed the absence of maternal environment effect on the performance of the seedlings.

Increase of apatite dissolution rate by Scots pine roots associated or not with Burkholderia glathei PML1(12)Rp in open-system flow microcosms

The release of nutritive elements through apatite dissolution represents the main source of phosphorus, calcium, and several micronutrients (e.g., Zn, Cu) for organisms in non-fertilized forest ecosystems. The aim of this study was to quantify, for the first time, the dissolution rate of apatite grains by tree roots that were or were not associated with a mineral weathering bacterial strain, and by various acids known to be produced by tree roots and soil bacterial strains in open-system flow microcosms. In addition, we explored whether the mobilization of trace elements (including rare earth elements) upon apatite dissolution was affected by the presence of trees and associated microorganisms. The dissolution rate of apatite by Scots pine plants that were or were not inoculated with the strain Burkholderia glathei PML1(12)Rp, and by inorganic (nitric) and organic (citric, oxalic and gluconic) acids at pH 5.5, 4.8, 3.8, 3.5, 3.0, and 2.0 was monitored in two controlled experiments: “plant–bacteria interaction” and “inorganic and organic acids”. Analyses of the outlet solutions in the “plant–bacteria interaction” experiment showed that Scots pine roots and B. glathei PML1(12)Rp produced protons and organic acids such as gluconate, oxalate, acetate, and lactate. The weathering budget calculation revealed that Scots pines (with or without PML1(12)Rp) significantly increased (factor>10) the release of Ca, P, As, Sr, Zn, U, Y, and rare earth elements such as Ce, La, Nd from apatite, compared to control abiotic treatment. Scanning electron microscopy observation confirmed traces of apatite dissolution in contact of roots. Most dissolved elements were taken up by Scots pine roots, i.e., approximately 50% of Ca, 70% of P, 30% of As, 70% of Sr, 90% of Zn, and 100% of U, Y, and rare earth elements. Interestingly, no significant additional effect due to the bacterial strain PML1(12)Rp on apatite dissolution and Scots pine nutrition and growth was observed. The “inorganic and organic acids” experiment demonstrated that the apatite dissolution efficacy of organic acids was higher than for the inorganic acid and varied in function of the acids: oxalic acid>citric acid>gluconic acid>nitric acid for pH ⩽3.5. In addition, apatite dissolution increased with increasing acidity for each acid. Only oxalic acid generated non-stoichiometric release of calcium and phosphorus from apatite in the solution at pH ⩽3.5, due to the precipitation of Ca-oxalate crystals at apatite surfaces. Comparison of the experiments revealed that the apatite dissolution rate by Scots pines supplied with nutritive solution at pH 5.5 reached 2.0×10−13molcm−2s−1 and was equivalent to rates with nitric acid at pH 3.2, gluconic acid at pH 3.5, citric acid at pH 3.7, and oxalic acid at pH 3.8.Altogether our results highlight that, through the production of weathering agents, notably protons and organic acids, tree roots and root-associated microorganisms are able to significantly increase the release of macro- and micro-nutrients from apatite, thus maintaining high-nutrient conditions to support their growth.

Growth of Scots pine (Pinus sylvestris L.) on forest and former agricultural lands in Krynki Forest District

We’ve built this digital research platform to provide academics everywhere with fast, stable and secure digital access to our library of over 110,000 scholarly books and 800,000 journal articles. We’ve tested the platform in close cooperation with leading academic institutions. If you have any questions or you notice something doesn’t quite work as it should, please visit our <a href="/publishing/faq?lang=en" class="text-primary">Help/FAQ</a> page and let us know.