Rooting strategy of naturally regenerated beech in Silver birch and Scots pine woodlands

This study investigated the belowground development and strategy of late-successional European beech (Fagus sylvatica L.) in ageing natural Scots pine (Pinus sylvestris L.) and Silver birch (Betula pendula Roth.) woodlands in a French volcanic mid-elevation area. For this purpose root biomass, root profile and fine-root architecture of competitor trees were examined in 53 mixed pine–beech and 42 birch–beech woodlands along a stand maturation gradient, using the root auger technique (0–75-cm). The total beech fine-root biomass highly correlated with aerial dimensions such as stem height and girth, whereas it moderately correlated with its age, thus indicating the effects of competition. Basic stand biometric data such as stand density and basal area had no significant effect on beech root biomass. Conversely, competition indices taking into account the vertical dimensions of competitor trees were efficient, probably due to redundancy with beech height. At similar age and height, beeches under birch had a greater belowground development than beeches under pine. Each species exhibited specific rooting pattern and plasticity of fine-root architecture along the gradients of stand maturation and competition. Beech had a heart-shaped rooting habit in both mixings, which strongly increased along stand maturation. Its fine-root system adopted a foraging strategy to respond to increasing stand competition. The Scots pine fine-root system was plate-like and showed a low morphological plasticity, thus presumably a conservative strategy. Silver birch exhibited a high biomass and a foraging capacity in the topsoil but a loose root system in the subsoil. The coexistence of pine and beech roots in the upper soil presumably leads to a high belowground competition. Beech root system becomes predominant throughout the soil profile and it adopts an efficient foraging strategy, but at the expense of its belowground development. Conversely, the niche partitioning strategy between beech and birch may explain why beech develops strongly belowground in spite of the fact that birch has a dense rooting and a competitive fine-root architecture. As a consequence, beech mid-term regeneration and development may be facilitated under birch as compared with pine.     

Betula pendula: A Promising Candidate for Phytoremediation of TCE in Northern Climates

Betula pendula (Silver birch) trees growing on two contaminated sites were evaluated to assess their capacity to phytoscreen and phytoremediate chlorinated aliphatic compounds and heavy metals. Both locations are industrially-contaminated properties in central Sweden. The first was the site of a trichloroethylene (TCE) spill in the 1980s while the second was polluted with heavy metals by burning industrial wastes. In both cases, sap and sapwood from Silver birch trees were collected and analyzed for either chlorinated aliphatic compounds or heavy metals. These results were compared to analyses of the surface soil, vadose zone pore air and groundwater. Silver birch demonstrated the potential to phytoscreen and possibly phytoremediate TCE and related compounds, but it did not demonstrate the ability to effectively phytoextract heavy metals when compared with hyperaccumulator plants. The capacity of Silver birch to phytoremediate TCE appears comparable to tree species that have been employed in field-scale TCE phytoremediation efforts, such as Populus spp. and Eucalyptus sideroxylon rosea.     

Root development and configuration in intensively managed radiata pine plantations

Summary In south-east Australia, where radiata pine (Pinus radiata D. Don) is grown on sandy soils low in nutrients and short of water, early establishment, and rapid growth to canopy closure lead to increased productivity. At this stage demands for nutrients and water are high, and trees respond vigorously to silvicultural inputs.For several months after transplanting in winter roots are confined within a narrow planting wedge, low temperature restricts new root growth and slows recovery from water stress in plants. From spring, depending upon the configuration and vigour of the roots transplanted, lateral roots extend radially throughout the soil.Although there were small decreases in concentration of roots radially from the stems of very young trees, such spatial differences disappeared between ages 2 and 3, so that rooting density was independent of distance from the stem. The pattern of vertical distribution of lateral roots was not influenced by age and 80–90% of the lateral roots were within the top 30 cm soil. Roots developed rapidly as the trees grew towards canopy closure, but in general the rooting densities of these pines are among the lowest reported for plants. In rapidly growing trees approaching canopy closure, the secondary thickening of the lateral roots was sufficient to double the weight of roots without altering root length.Knowledge about root growth and root configuration during the early phase of plantation development will assist management decisions where intensive silviculture is practiced, and hence ensure the most efficient use of nutrients and water.     

Mycorrhizas and C and N transformations in the rhizospheres of Pinus sylvestris,Picea abies and Betula pendula seedlings

Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L.) and silver birch (Betula pendula L.) seedlings were grown in a greenhouse for four months in three different soils. The soils were from a field afforestation site on former agricultural land: soil from a pine site, soil from a spruce site and soil from a birch site. Pots without seedlings were included. The aim was to discover, independent of the effects of the different quality of aboveground litter and microclimate under the tree species, whether the roots change the microbial activities and chemical characteristics of the soil, whether the changes are dependent on the tree species, and whether the changes vary in different soils. Pine, spruce and birch had, on average, five, one and six meters of roots, respectively. Birch had by far the highest number of short root tips, on average 11 450 per seedling, compared to 1900 and 450 in pine and spruce seedlings, respectively. The majority of the short roots of pine and spruce were brown sheathed mycorrhizas, and those of birch were mycorrhizas in an early stage of development. The seedlings caused no major changes in either the soil pH or the concentrations of nutrients in the soils, but did affect the microbial characteristics of the soils. The effect of the tree species did not differ in different soils. Microbial biomass C and N, C mineralization rate and the concentration of ergosterol were all higher under birch and pine than under spruce and in plantless soils. Nitrate concentrations were lowest under pine and birch, but rates of net N mineralization, nitrification and denitrification did not differ under different seedlings. The stimulative effect of pine and especially birch on soil microbes was possibly due to them having more roots and releasing more root exudates to soil. There were, however, indications that not only the length/mass of roots determined the changes in microbial activities, but also differences in root activities per unit of root or in the quality of root exudates.     

Architectural Tradeoffs between Adventitious and Basal Roots for Phosphorus Acquisition

Adventitious rooting contributes to efficient phosphorus acquisition by enhancing topsoil foraging. However, metabolic investment in adventitious roots may retard the development of other root classes such as basal roots, which are also important for phosphorus acquisition. In this study we quantitatively assessed the potential effects of adventitious rooting on basal root growth and whole plant phosphorus acquisition in young bean plants. The geometric simulation model SimRoot was used to dynamically model root systems with varying architecture and C availability growing for 21 days at 3 planting depths in 3 soil types with contrasting nutrient mobility. Simulated root architectures, tradeoffs between adventitious and basal root growth, and phosphorus acquisition were validated with empirical measurements. Phosphorus acquisition and phosphorus acquisition efficiency (defined as mol phosphorus acquired per mol C allocated to roots) were estimated for plants growing in soil in which phosphorus availability was uniform with depth or was greatest in the topsoil, as occurs in most natural soils. Phosphorus acquisition and acquisition efficiency increased with increasing allocation to adventitious roots in stratified soil, due to increased phosphorus depletion of surface soil. In uniform soil, increased adventitious rooting decreased phosphorus acquisition by reducing the growth of lateral roots arising from the tap root and basal roots. The benefit of adventitious roots for phosphorus acquisition was dependent on the specific respiration rate of adventitious roots as well as on whether overall C allocation to root growth was increased, as occurs in plants under phosphorus stress, or was lower, as observed in unstressed plants. In stratified soil, adventitious rooting reduced the growth of tap and basal lateral roots, yet phosphorus acquisition increased by up to 10% when total C allocation to roots was high and adventitious root respiration was similar to that in basal roots. With C allocation to roots decreased by 38%, adventitious roots still increased phosphorus acquisition by 5%. Allocation to adventitious roots enhanced phosphorus acquisition and efficiency as long as the specific respiration of adventitious roots was similar to that of basal roots and less than twice that of tap roots. When adventitious roots were assigned greater specific respiration rates, increased adventitious rooting reduced phosphorus acquisition and efficiency by diverting carbohydrate from other root types. Varying the phosphorus diffusion coefficient to reflect varying mobilities in different soil types had little effect on the value of adventitious rooting for phosphorus acquisition. Adventitious roots benefited plants regardless of basal root growth angle. Seed planting depth only affected phosphorus uptake and efficiency when seed was planted below the high phosphorus surface stratum. Our results confirm the importance of root respiration in nutrient foraging strategies, and demonstrate functional tradeoffs among distinct components of the root system. These results will be useful in developing ideotypes for more nutrient efficient crops.     

胡杨根系水力提升作用的证据及其生态学意义

生长在塔里木河流域的荒漠河岸林植被虽长期忍受着高温和干旱的威胁, 然而它们却能够一直延续并保存至今。除了植物深根系吸水作用外, 另一个更主要的原因可能就是荒漠河岸林植被存在水力提升的效应。该文采用HRM热比率法茎流仪对3株胡杨(Populus euphratica)主根和侧根的液流速率分别进行了为期4 d的连续监测; 利用自动气象站对微气象因子：风速、空气相对湿度、叶面温度和地表温度进行连续监测; 同时采用了烘干法对不同深度土层在不同时刻的土壤含水率进行了取样分析。试验结果表明：胡杨主根液流在白天和夜间均表现为正值, 相反的, 胡杨侧根液流速率则出现了明显的夜间负向流动。胡杨根系0~120 cm土层土壤水分含量具有下湿上干的变化趋势; 胡杨侧根在夜间发生负向流动后, 土壤含水率显著升高, 尤其在60~120 cm土层中, 4:00土壤含水率上升幅度达到4:00时刻土壤含水率的22%~26%。影响胡杨侧根液流速率的主要气象因子主要是叶面水汽压亏缺。     

Phosphatase production by mycorrhizal fungi

Summary Sheathing mycorrhizal fungi have been shown to possess phosphatase enzymes which can hydrolyse inositol hexaphosphate. In a range of mycorrhizal fungi, this activity was often greater than in two common decomposer basidiomycetes. Mycorrhizal birch and pine roots both produce phosphatases. In birch production is inversely related to the inorganic phosphorus concentration in the growth medium. Mycorrhizas reduce phosphatase activity compared with non-mycorrhizal plants.Phosphatase production by basidiomycete fungi in liquid culture is independent of P in the medium. Saprophytic basidiomycetes tend to incorporate hydrolysed phosphate into their biomass. In contrast mycorrhizal fungi release more into solution than they absorb. The significance of this difference in relation to the supply of nutrients to plants is discussed.     

红松,白桦的氮营养行为及其种间分异

对红松、白桦的吸收空间和吸收N素的时间 (季节 )、数量、形态的研究表明 ,在混交情况下 ,白桦表现出较典型的浅根性特征 ,吸收根主要集中在土壤表层 ;红松则具有深根性趋势 ,其吸收根在下层土壤空间的分布明显增加 .白桦吸收N素养分的季节比较集中 ,具有明显的峰期 ;而受白桦庇荫的红松则在整个生长季中一直比较平缓地吸收N素 ,峰期不甚明显 .白桦对N的消耗量较大 ;而红松对N的消耗量则相对较小 ,N利用效率比白桦高 34% .在对N素养分化学形态的偏向选择性方面 ,白桦较喜NO-3 N ,而红松则较偏好NH 4 N .     

Water relations in silver birch during springtime: How is sap pressurised?

• Positive sap pressures are produced in the xylem of birch trees in boreal conditions during the time between the thawing of the soil and bud break. During this period, xylem embolisms accumulated during wintertime are refilled with water. The mechanism for xylem sap pressurization and its environmental drivers are not well known.
• We measured xylem sap flow, xylem sap pressure, xylem sap osmotic concentration, xylem and whole stem diameter changes, and stem and root non‐structural carbohydrate concentrations, along with meteorological conditions at two sites in Finland during and after the sap pressurisation period.
• The diurnal dynamics of xylem sap pressure and sap flow during the sap pressurisation period varied, but were more often opposite to the diurnal pattern after bud burst, i.e. sap pressure increased and sap flow rate mostly decreased when temperature increased. Net conversion of soluble sugars to starch in the stem and roots occurred during the sap pressurisation period. Xylem sap osmotic pressure was small in comparison to total sap pressure, and it did not follow changes in environmental conditions or tree water relations.
• Based on these findings, we suggest that xylem sap pressurisation and embolism refilling occur gradually over a few weeks through water transfer from parenchyma cells to xylem vessels during daytime, and then the parenchyma are refilled mostly during nighttime by water uptake from soil. Possible drivers for water transfer from parenchyma cells to vessels are discussed. Also the functioning of thermal dissipation probes in conditions of changing stem water content is discussed.

     

Response of vesicular-arbuscular mycorrhizas of maize to various rates of P addition to different rooting zones

Colonization of plant roots by vesicular-arbuscular mycorrhizal fungi is known to be reduced as the phosphorus nutrition of the plant is increased. It is generally accepted that the concentration of P in the plant rather than the soil regulates VAM colonization. Whether it is the shoot P concentration, the mean P concentration in the root system or the P concentration in the specific root being colonized is not known, but is of agronomic significance because fertilizer P is frequently applied in concentrated zones which would be expected to result in higher P concentration in roots growing in the fertilized zone than in the remainder of the root system. Growth chamber and field experiments were conducted to determine the effect on colonization of supplying varying amounts of P to different portions of the rooting zone. In growth chamber studies using a split-pot technique, the proportion of maize (Zea mays L.) root length containing arbuscules in a high-P zone was lower than that of roots of the same plant growing in a low- or medium-P zone. Root P concentration was higher in the high-P zone. In a field experiment conducted over a two-year period, VAM colonization of roots of young maize plants growing in fertilized soil was affected differently than that of roots growing outside the fertilized zone. A small addition of fertilizer P increased colonization of roots in the fertilized soil, but further additions resulted in an abrupt decline followed by a slower further decline, although colonization was not eliminated even by rates of 1600 g P g^-1 soil. Colonization of roots growing outside the fertilized zone declined gradually with increasing P addition but the overall decline was less than for roots in the fertilized zone. The data support the hypothesis that it is P concentration in the portion of the root system being colonized rather than the general P status of the plant which regulates VAM colonization. The agronomic implication of this is that, although a fertilizer band may reduce VAM colonization of roots in the band volume, roots growing outside this volume may be well colonized so the mycorrhizal symbiosis may be an important contributor to P nutrition.     

Reverse flow of sap in tree roots and downward siphoning of water by Grevillea robusta

1. Constant-power heat-balance sap flow gauges were used to compare sap flow in vertical and lateral roots of Grevillea robusta trees growing without access to ground water at a semiarid site in Kenya.
2. Reversal of sap flow occurred when root systems crossed gradients in soil water potential. Measurement of changes in the direction of flow was possible because of the symmetrical construction of the sap flow gauges; gradients in temperature across the gauges, and thus computed rates of sap flow, changed sign when reverse flow occurred.
3. Reverse flow in roots descending vertically from the base of the tree occurred, while uptake by lateral roots continued, when the top of the soil profile was wetter than the subsoil. The transfer of water downwards by root systems, from high to low soil water potential, was termed 'downward siphoning'; this is the reverse of hydraulic lift.
4. Downward siphoning was induced by the first rain at the end of the dry season and by irrigation of the soil surface during a dry period.
5. Downward siphoning may be an important component of the soil water balance where there are large gradients in water potential across root systems, from a wet soil surface downwards. By transferring water beyond the reach of shallow-rooted neighbours, downward siphoning may enhance the competitiveness of deep-rooted perennials.     

Soil strength influences wheat root interactions with soil macropores

Deep rooting is critical for access to water and nutrients found in subsoil. However, damage to soil structure and the natural increase in soil strength with depth, often impedes root penetration. Evidence suggests that roots use macropores (soil cavities greater than 75 μm) to bypass strong soil layers. If roots have to exploit structures, a key trait conferring deep rooting will be the ability to locate existing pore networks; a trait called trematotropism. In this study, artificial macropores were created in repacked soil columns at bulk densities of 1.6 g cm⁻³ and 1.2 g cm⁻³, representing compact and loose soil. Near isogenic lines of wheat, Rht-B1a and Rht-B1c, were planted and root–macropore interactions were visualized and quantified using X-ray computed tomography. In compact soil, 68.8% of root–macropore interactions resulted in pore colonization, compared with 12.5% in loose soil. Changes in root growth trajectory following pore interaction were also quantified, with 21.0% of roots changing direction (±3°) in loose soil compared with 76.0% in compact soil. These results indicate that colonization of macropores is an important strategy of wheat roots in compacted subsoil. Management practices to reduce subsoil compaction and encourage macropore formation could offer significant advantage in helping wheat roots penetrate deeper into subsoil.     

Abscisic acid promotes root system development in birch tissue culture: a comparison to aspen culture and conventional rooting‐related growth regulators

The research aim was to assess the effects of the plant hormone abscisic acid (ABA) and the growth regulator paclobutrazol (PBZ) on root system development during the in vitro culture of different birch and aspen genotypes. The studied genotypes involved two aspen (Populus tremula and Populus tremuloides × P. tremula) and two silver birch (Betula pendula) trees, with one of the birches characterized by its inability to root in vitro. For experiments, apical shoot segments were cultured on nutrient medium enriched with either ABA or PBZ. Additionally, the analysis of the endogenous hormones in shoots developed on hormone‐free medium was conducted by high‐performance liquid chromatography. The endogenous concentration of auxin indole‐3‐acetic acid was much higher in the aspens than that in the birches, while the highest concentration of ABA was found in the root‐forming birch. The culturing of this birch genotype on medium enriched with ABA resulted in an increased root length and a higher number of lateral roots without any negative effect on either shoot growth or adventitious root (AR) formation, although these two processes were largely inhibited by ABA in the aspens. Meanwhile, PBZ promoted AR formation in both aspen and birch cultures but impaired secondary root formation and shoot growth in birches. These results suggest the use of ABA for the in vitro rooting of birches and PBZ for the rooting of aspens.     

Long-term inducible resistance in birch foliage: triggering cues and efficacy on a defoliator

Heavy damage of the mountain birch foliage, as well as application of small amounts of insect frass to the soil beneath the trees, reduced growth of Epirrita autumnata larvae reared in these trees in the following year. Foliage damage in the previous year decreased larval survival, too. Both foliage damage and insect frass in the soil decreased a fecundity index which combined the effects of size and survival. Because application of small amounts of fertilizers had an effect indistinguishable from that of insect frass, the effect of the frass may base on responses of trees to an increase in soil nutrient concentration in mid-summer. In previously untreated control trees, all performance indices (growth, survival, and egg production) of Epirrita correlated positively with the distance of the birch from the closest birch defoliated in the previous year, indicating communication between adjacent trees. Epirrita egg production in trees that had been both defoliated and treated with frass in the previous summer was at least 70% lower than in previously unmanipulated control trees.     

Urban tree root systems and their survival near houses analyzed using ground penetrating radar and sap flow techniques

Root systems of two mature Field maple trees (Acer campestre L.) growing in both shaded and non-shaded sites, on clay soil in an urban environment, were analyzed by ground penetrating radar (GPR), light microscope and sap flow techniques. The ground surface above the root systems was covered by asphalt. However, a small piece of garden existed near the non-shaded tree, and root area of roots growing in this direction increased significantly, due to a presumed increase in available water and nutrients. However, no garden was present near the shaded tree, therefore roots remaining under the asphalt surface did not increase in area in any particular direction. Maximum rooting depth of shaded and exposed trees, as determined by GPR, was approximately 1.4 and 1.7 m, respectively. The trees utilized relatively large amounts of water for transpiration, i.e. 65–140 l per fine summer day and in average 10 m³ per growing season. However, transpiration expressed per root surface area (and/or whole root system enveloping area) was practically the same in both trees, i.e. 1 dm³ m^-2 d^-1 or almost 100 dm³ m^-2 per growing season. These figures represented about 50% of potential evapotranspiration when considering projected crown areas. Increased transpiration under long-term high evaporation demands may cause occasional local drying of soil around roots, associated with soil shrinking in clay, which can be followed by serious damage to buildings.     

Influence of subsoil zinc on dry matter production,seed yield and distribution of zinc in oilseed rape genotypes differing in zinc efficiency

The effects of Zn supply (+Zn: 1 mg kg^–1 soil, -Zn: no Zn added) in subsoil were examined in three genotypes of Brassica napus (Zhongyou 821, Xinza 2, Narendra) and one genotype of Brassica juncea (CSIRO-1) in a glasshouse experiment in pots (100 cm long, 10.5 cm diameter). The topsoil (upper 20 cm soil in pots) was supplied with Zn in all treatments whereas Zn was either supplied or omitted from the subsoil. Supplying Zn to subsoil significantly increased the root growth in the lower zone, markedly decreased the number of aborted and unfilled pods plant^–1 and significantly increased the number of developed pods plant^–1, number of seeds pod^–1, individual seed weight and overall seed yield. Subsoil Zn also significantly increased the Zn concentration and Zn content of seed and improved the ratio of Zn uptake by seed to total Zn uptake by seed and shoots. These effects of subsoil Zn were more pronounced in Zhongyou 821, Xinza 2 and Narendra compared with CSIRO-1. CSIRO-I had 92% Zn efficiency (ratio of -Zn subsoil seed yield to +Zn subsoil seed yield expressed in percentage) compared with 63% for Zhongyou 821. Among the four genotypes, CSIRO-1 had the lowest Zn concentration in roots and shoots but highest Zn concentration and content in seed, suggesting it has a superior Zn transport mechanism from source (roots) to sink (seed). CSIRO-1 also significantly decreased the rhizosphere pH in lower rooting zone (20-93 cm) in -Zn subsoil treatment compared with +Zn treatment.     

红松、白桦的氮营养行为及其种间分异

对红松、白桦的吸收空间和吸收N素的时间(季节)、数量、形态的研究表明,在混交情况下,白桦表现出较典型的浅根性特征,吸收根主要集中在土壤表层;红松则具有深根性趋势,其吸收根在下层土壤空间的分布明显增加.白桦吸收N素养分的季节比较集中,具有明显的峰期;而受白桦庇荫的红松则在整个生长季中一直比较平缓地吸收N素,峰期不甚明显.白桦对N的消耗量较大;而红松对N的消耗量则相对较小,N利用效率比白桦高34%.在对N素养分化学形态的偏向选择性方面,白桦较喜NO₃^--N,而红松则较偏好NH₄⁺-N.     

Abscisic acid concentration,root pH and anatomy do not explain growth differences of chickpea (Cicer arietinum L.) and lupin (Lupinus angustifolius L.) on acid and alkaline soils

The ABA concentrations of leaves, roots, soils and transport fluids of chickpea and lupin plants growing in acid (pH=4.8) and alkaline (pH=8.0) soils and an acid soil with an alkaline subsoil and an alkaline soil with an acid subsoil were measured with the aim of explaining the poor growth of narrow-leafed lupins in alkaline soil. The ABA concentration in the leaves was higher in lupin than chickpea, but did not differ when the plants were grown in alkaline compared to acid soil. The ABA concentration of the roots and xylem sap of lupin did not differ significantly when grown in acid or alkaline soil. Chickpea roots and xylem sap had, however, lower ABA concentrations in acid soil. The ABA concentration in the soil solution was higher in the acid than in the alkaline soil. Roots of lupin and chickpea showed no suberization of the hypodermis or exodermis whether grown aeroponically or hydroponically and the pH of the cytoplasm did not change significantly when root cells of lupin and chickpea were exposed to external pHs of 4.8 or 8.0. The chickpea roots had greater suberization of the endodermal cells adjacent to radial xylem rays and maintained a slightly higher vacuolar pH than lupin in both acid and alkaline external media, but these small differences are insufficient to explain the reductions in lupin growth in alkaline soil.     

Model Trials for Phytoremediation of Hydrocarbon-Contaminated Sites by the Use of Different Plant Species

In order to further the development of plant-based remediation of sites contaminated by carbo-chemical and petro-chemical industries, the penetration of the roots of Phragmites australis in contaminated soil substrate was studied in model trials. The series of experiments contained model substrate with firm bitumen and tar. In terms of the level of root penetration, the roots and rhizomes penetrated equally through the middle of the pot and at the edges as well as coming up through the bottom. There were differences between the density of the root systems in the topsoil of the two variations, with the roots in the sample with a 3.5 -cm bitumen layer being more dense. The experiment also showed that shallow rooting plants can penetrate thick barriers and are suitable for planting in contaminated areas. In the subsoil zone, which contained many roots, a reduction of up to 85% in the MOH content was observed. In a second series of long-term pot experiments, the stimulation of hydrocarbon remediation by Phragmites australis, Alnus glutinosa, and Robinia pseudoacacia was studied. In the subsoil zone, which contained many roots, a reduction of up to 64% in the hydrocarbon content was determined. In the comparison between the cropped and noncropped treatments, the decontamination ratio was up to 40% higher in the cropped pots than in the pots without plants. For a determination of microbial activity, two enzymes (catalase, ß-glucosidase) and microbial biomass were measured. Variants with plants showed higher microbial activities than uncropped pots. By increasing “biostimulation,” pollution and also the leaching of pollutants can be reduced.     

Adventitious roots as a source of information in reconstructing the activity of modern aeolian processes in the temperate climate zone: A case study from the Kozłów sandy area (SW Poland)

This paper presents a spatial-temporal reconstruction of inland dune movements at an anthropogenic active sandy area known as the Kozłów Desert, SW Poland. This unique sandy area, with assemblages of aeolian forms typical of “true” deserts, is an inactive military training ground (decommissioned in 1992) where military activity led to the initiation of geomorphic processes. The reconstruction was carried out based on the growth reaction characteristics of Scots pine (Pinus sylvestris L.) and downy birch (Betula pubescens L.) trees. 14 increment cores were collected from 12 trees and analysed with standard dendrochronological techniques. Samples of adventitious roots from all the trees examined were collected and prepared to extend the analyses and check their usefulness in dating modern geomorphic processes. The adventitious roots of pine and birch were found to react differently to burial, in terms of both reaction time and the shape of the root system. Growth-ring widths and wood anatomy were indicative of sudden or multi-stage sand movement, thus confirming the usefulness of adventitious roots as an additional source of information about aeolian process activity. More broadly, the study shows that the dynamics of landforming processes can be assessed more accurately and reliably by using such a combination of methods, comparing data from roots to data from tree trunks.