Fine Tree Research Articles

영조 대 숭례문 문루의 하층 사용과 건축 변화에 대한 연구

This research work is to analyze architectural characteristics of Sungnyemun especially in King Yeongjo`s reign in Joseon dynasty. The result of this research is summarized as following: 1. The architectural characteristics of Sungnyemun in King Yeongjo`s reign are closely related with Confucian ceremonies such as Jeon-jwa and Heon-goek-rye. To perform these ceremonies, some lower walls of Sungnyemun`s wooden pavilion were removed and used as ceremonial space. And after ceremony it was restored. 2. The floor type of center bay of the 1st story of wooden pavilion should have a type of floor using long and narrow fine tree plate, which is same type before the repair work of 1960`s dismantlement. 3. The width of east stairway which is reached to east small gate, was changed just before Japanese`s rule(1910~1945), should be broaden than present width, which is proven through the recent excavation. 4. The reason of asymmetric characteristic of locations of both east and west narrow-gate, and widths of east and west stairway, are related with order of King`s ceremony. * Jeonjwa : a ceremony to see national affairs or receive royalty from officials in main hall or main gate of palace in Joseon dynasty (some times open to public) * Heon-goek-rye : a ceremony after win a war and offering to king enemy`s ear or head in Joseon dynasty.

Impacts of forest post thinning residues on soil chemistry, fauna and roots: Implications of residue removal in Finland

There is increasing interest in removing greater amounts of non-timber residues from forests for use in energy production. As part of a study aimed at elucidating the ecological impacts of these practices in Finland, piles of thinning residues of contrasting mass per unit area were established in 2004 around the base of individual Scots pine trees. As part of an NSF funded undergraduate training program, we have sampled the soil under these residue piles to evaluate the effect of leaving different amounts of residue on site to supply nutrients for remaining trees. Aboveground tree biomass production was significantly higher with higher levels of post-harvest residue retention. However, changes in soil chemistry were minimal and inconsistent with increasing residue amounts. Fine (<1mm) tree root biomass showed little response to residue levels, but specific root length (length per unit mass) and ectomycorrhizal root tip abundance showed significant increases in the highest residue addition compared to the no-addition control. This may suggest a greater root searching strategy under high residue levels. There was no evidence of residue effect on soil nematodes but a consistent increase in abundance of 0–2mm length enchytraeids with increased residue. This may be a result of higher rates of asexual reproduction under residues. Soil arthropod abundances did not correlate with residue levels. Even in this cold boreal forest ecosystem, it is possible that sampling 5years after residue placement we may have missed some of the early influence of decomposition of more labile fractions of the residues on soil organisms and processes. It is likely that the current phase of woody material decomposition will have lesser effects on soil biology.

Productivity of Ephemeral Headwater Riparian Forests Impacted by Sedimentation in the Southeastern United States Coastal Plain

Riparian forests serve an essential function in improving water quality through the filtering of sediments and nutrients from surface runoff. However, little is known about the impact of sediment deposition on productivity of riparian forests. Sediment inputs may act as a subsidy to forest productivity by providing additional nutrients for plant uptake or may act as a stress by creating anoxic soil conditions. This study determined how sediment deposition affected riparian forests along ephemeral headwater streams at Ft. Benning, Georgia, USA. Above- and belowground productivity, leaf-area index (LAI), and standing crop biomass for fine roots, shrubs, and trees were compared along a gradient of present sedimentation rates in 17 riparian forests. Annual litterfall production was determined from monthly collections using 0.25- m(2) traps; woody biomass was determined from annual diameter at breast height (DBH) measurements using species-specific allometric equations; fine root productivity was determined using sequential coring; LAI was measured by expanding specific leaf area by annual litterfall production; and shrub biomass was determined using species-specific biomass equations based on height and root collar diameter. Significant declines in litterfall, woody biomass production, fine root production, LAI, and shrub biomass were found with as little as 0.1 to 0.4 cm yr(-2) sedimentation. We conclude that the levels of sedimentation in this study do not subsidize growth in ephemeral headwater riparian forests but instead create a stress similar to that found under flooded conditions.

Trace elements accumulation in walnut growing on residential areas in Ukraine

The Walnut (Jugland regia L,) is wide spread on the territory of Ukraine, This big fine tree isgrown both in orchards, park, in roadside green belts, It is popular for high nutritive value oftheir nuts, bactericidal properties of leaves, volatile production. Pilot investigation has beenheld to reveal trace elements accumulation in walnut depending on traits of environment inurban and rural areas,Leaves and nuts of walnut have been sampled in 2003-2004 September in different parts ofthe country, Leaf, kernel and nutshell have been ashed and analysed (ESA) separately,Main results of investigation are as follows: accumulation of phosphorus, copper, zinc andlead in kernel estimated; probably nutshell serves as a barrier for strontium accumulation inkernel; lead concentration is higher in kernel of walnut growing along motorway and may canreach sanitary limit; zinc concentration inversely is higher on rural areas; arsenic has beenfind in matter sampled near railway roads,In future more detailed investigation of Walnut could make it possible to estimate the walnutas an instrument for pollution monitoring and control.

Tree fine root Ca/Al molar ratio – Indicator of Al and acidity stress

High soil acidity and elevated soil Al concentrations limit plant growth in many terrestrial ecosystems. Aluminium toxicity can be ameliorated by Ca. Thus, Ca/Al molar ratios in soil solution and in plant tissues have been proposed as superior indicators than Al concentration itself for evaluating the Al toxicity stress to trees (Cronan & Grigal, J Environ Qual 1995;24:209 – 226). This article presents an overview of publications since 1995 where the reduced Ca/Al ratio in fine tree roots has been used as an indicator of stress for Al and/or soil acidity. The main aim of this review was to evaluate the use and the critical threshold of the fine root Ca/Al ratio as a potential indicator for Al toxicity stress to trees in acid soils. Based on the reviewed literature, the fine root Ca/Al molar ratio was strongly negatively related to Al stress in small tree seedlings in controlled environments, whereas the response was not clear under field conditions where other environmental factors interact. Fine root Ca/Al ranged from 0.03 to 17 in tree seedlings and from 0.1 to 18 in mature trees depending on experimental and site conditions, as well as the tolerance and uptake mechanisms of the different tree species. Fine root Ca/Al was positively related to the soil solution Ca/Al molar ratio. Fine root Ca/Al ratios were related positively to fine root length, growth, specific root length, and biomass, and negatively to root diameter, callose formation, respiration chain activity, starch concentration, and root necromass. A number of relationships have been also found between the fine root Ca/Al and above-ground seedling and/or mature tree growth and nutrient uptake. The critical thresholds for the Ca/Al fine root ratio of 0.2 suggested by Cronan and Grigal (1995) is estimated to represent 90% risk of inverse impact on root and above-ground tree growth. Values of Ca/Al molar ratio in the fine roots of mature trees were only rarely determined below the critical 0.2. The caveats for the use and the interpretation of Ca/Al ratio in fine roots have been addressed in detail. A protocol for root processing and elemental analysis to obtain reliable and comparable results of Ca and Al concentrations in roots is also provided. The article concludes with recommendations for a wider use of the Ca/Al ratio in roots as a bioindicator of Al toxicity to trees in acid soils.

Fine roots refilling process in an artificial gap in a Picea mongolica forest

Picea mongolica is an endemic but endangered species in China. The spruce forest is only found in sandy forest-steppe ecotones. In this study, we examined the initial response of the quantity and refilling process of fine roots in an artificial canopy gap with a diameter of 36 m in a P. mongolica forest. Under the canopy, the fine root length densities of trees, shrubs and herbs were 2,622,864 and 3,086 m·m−2, respectively. The fine root biomass of trees, shrubs and herbs were 148, 62 and 65 g·m−2, respectively. In the gap, the fine root length density of trees was 151 m·m−2. The mean fine root densities of shrubs and herbs in the gap were 756 and 2,568 m·m−2. The fine root biomass of trees, shrubs and herbs were 9, 52 and 47 g·m−2, respectively. Two growing seasons after the gap creation, hardly any fine tree roots were found in the middle of the gap. The living tree roots in the gap edge zone were mainly located within a 4.5 m distance from the standing trees. Indices developed to show the influence of trees on fine root length density clearly revealed the effect of the vicinity of living trees on fine root length density. The root densities of shrubs and herbs did not show a clear response to gap creation despite the increase of their foliage. Our results suggest that in P. mongolica forests a gap disturbance creates a distinct tree root gap and that the gap edge trees do not extend their root systems rapidly into the formed root gap.

Testing research for assessing suitability of multi-species of trees introduced in habitats in hilly and gully areas of Loess Plateau

To enrich resource of species, 105 arbor species (25 genera, 15 families) were introduced to the hilly and gully areas on Loess Plateau. By acclimation and selection, more than 90 tree species (12 genera, 8 families) were identified as fine species, including trees suitable for sloping fields such as Pinus sylvestri var mongolica, Pinus tabulaeformis, Platycladus orientalis, and Robinia pseudoacacia, trees suitable for gully bottoms such as Populus davidiana, Populus diversifolia, and Salix cheilophila and non-timber trees such as Prunus armeniaca, Ziziphus jujuba and Prunus persica. For those fine trees, habitat conditions and regularity of requirement of water and fertilizers were studied and then habitat ranges were given. From research results, it could be seen that Robinia pseudoacacia consumed more water, but it could improve the content of organic matters in soil; by contrast, Pinus tabulaeformis and Platycladus orientalis consumed less water and were suitable for dry sloping fields; species of apricot were suitable for sunny or semi-shady sloping fields with good conditions of water and fertilizer; species of pear were suitable for both shady sloping fields and sunny sloping fields; species of Chinese date were suitable for sunny sloping fields.

Response of fine roots to an experimental gap in a boreal Picea abies forest

We examined the initial response of the quantity and distribution of fine roots to the creation of an experimental canopy gap with a diameter of 50 m in a mature managed Norway spruce forest. Under the canopy, the fine root length densities of trees, shrubs, and grasses and herbs were 3207, 707 and 2738 m m−2, respectively. The fine root biomass of trees, shrubs, and grasses and herbs were 182, 47 and 52 g m−2, respectively. Two growing seasons after gap creation hardly any fine tree roots were found in the middle part of the gap. The living tree roots in the gap edge zone were mainly located within a 5-m distance from the standing edge trees. The indices developed here to show the influence of trees on fine root lenght density clearly revealed the effect of the vicinity of living trees on fine root lenght density. The root densities of grasses, herbs and dwarf shrubs did not show a clear response to gap creation despite the increase of their foliage. Our results suggest that in boreal spruce forests a gap disturbance creates a distinct tree root gap and that the gap edge trees do not extend their root systems rapidly into the formed root gap.

Soil properties under a Pinus radiata - ryegrass silvopastoral system in New Zealand. Part I. Soil N and moisture availability, soil C, and tree growth

Understanding the changes in soil properties in silvopastoral systems is important in regulating the interactions between tree and understorey pastures. In this study, the effects of understorey management on soil mineral N and moisture availability, soil temperature, soil C, and tree growth were investigated in a seven-year-old silvopastoral agroforestry experiment in Canterbury, New Zealand. The systems included understorey treatments of bare ground and ryegrass (Lolium perenne) pasture. Soil mineral N, moisture content, and temperature were monitored from July 1997 to July 1998 in two positions (0.9 and 3.5 m north of tree rows) and two soil depths (0–10 and 10–20 cm). Soil C and N in the 0–10 cm depth were higher in the ryegrass than in the bare ground plots, reflecting the organic C and N input in the ryegrass plots, as well as greater N loss from the bare ground plots in the form of nitrate leaching and/or denitrification. Soil C was higher in the position 0.9 m than 3.5 m away from the tree rows, possibly caused by the greater C input from decomposing fine tree roots and needle litterfall at the 0.9 m position. Soil moisture availability was greater in the bare ground than in the ryegrass plots in the summer. No effect of understorey management on soil temperature was found. Soil nitrate levels were lower in the ryegrass plots and may be limiting when soil moisture supply was adequate. Tree volume growth from winter 1997 to 1998 was significantly greater in the bare ground treatment, reflecting better soil moisture and N supply conditions.

Molecular identification of fine roots of trees from the Alps: reliable and fast DNA extraction and PCR-RFLP analyses of plastid DNA.

Fine roots of trees are intensively used as indicators to assess soil alterations, e.g. those owing to atmospheric inputs of acidifying substances, but their identification to species with morphological criteria is difficult. In this study, we established molecular techniques in order to identify fine roots of the 30 most common tree species of the Alps. We developed a protocol for efficient isolation of DNA from fine roots with extraction of DNA in the presence of polyvinylpyrrolidone (PVP) and polyvinylpolypyrrolidone (PVPP). The trnL (UAA) intron of plastid DNA was used as a marker for fine root identification. We amplified and sequenced this intron with plant universal primers. The size of the sequences ranged from 444 to 672 bp. A synoptic key for species identification was designed on the basis of restriction fragment patterns predicted from sequence data. Using the restriction enzyme TaqI as key enzyme, and where necessary HinfI, RsaI and CfoI, 16 taxa, including Picea abies, Larix decidua, Abies alba, and Fagus sylvatica, the dominant tree species of the Alpine region could be identified by agarose gel electrophoresis of restriction fragments. Fourteen taxa could be identified to the genus level, among them Quercus, Salix and Populus species. In a field study, conducted in a 20 x 30 m plot of a mixed forest with five tree species, fine roots of 43 out of 46 samples were identified and their distributions were mapped. These results demonstrate the utility of our DNA extraction method and of the trnL intron for the identification of fine tree roots.

Optimal algorithm for tree scheduling with unit time communication delays

A program is usually designed to act as a set of interacting tasks that can be used to construct a graph. These tasks can be assigned to processing elements in different ways. The scheduling problem is applied to defining an assignment of tasks in order to process elements that will optimise certain performance indices. One of the most important reasons for scheduling indices is to try to optimise the finishing time. The finishing time of a program is the result of two components: the computing time and communication delays. An optimal schedule is defined as the one that assigns tasks to processing elements in such a way as to finish at the earliest possible time. Completion of the optimum solution for arbitrary directed acyclic task graphs (DAGs) has been shown to be NP-complete. However, for some special classes of DAGs (such as fork, join, coarse-grain trees and some fine grain trees) many algorithms have been introduced to find optimal schedules. Note that most of these algorithms do not take into consideration the delays due to message passing among the processors. In the paper, the authors study the increase in time complexity due to communication delays. The particular problem that is addressed is the scheduling problem of the in-forest/out-forest. This paper introduces the first known linear time algorithm for finding the optimal schedule, for the special case of tree-like graphs, with unit time computation and unit time communication delays.

'Good &amp; Not Expensive...': Lord Harcourt's Nuneham Courtenay

The definitive historical study of the circumstances surrounding the creation of the village of Nuneham Courtenay, a few miles south-east of Oxford, was published more than thirty years ago. In a wide-ranging essay Mavis Batey recounted how the first Earl Harcourt, founding President of the Dilettanti Society, embarked in 1761 on the creation of an appropriate landscape garden to complement the setting of his newly completed classical villa. An essential preliminary to the landscaping was the necessity to remove the medieval village out of sight of views of the house, and as early as 1760 work had already begun on building a new settlement outside the confines of the park. Progress was rapid, and by the autumn of 1761 the new estate village placed astride the Oxford-Henley turnpike was a going concern (Fig. 1). There is little to add to Mrs Batey’s account of the controversy that accompanied this arrogant display of the power exercised by eighteenth-century landlords over the lives of their tenantry apart from taking the opportunity to record that her own further research has confirmed the tentative identification of Nuneham with Oliver Goldsmith’s critical poem The Deserted Village . An entry in the manuscript notebooks of Beilby Porteus, Bishop of London, recording a visit to Lord Harcourt on 20 August 1800, reads: The village was originally in the Park at no great distance from the House and consisted of pretty white cottages, scattered round a small piece of water and shaded with a number of very fine trees. The late Lord Harcourt thinking the village too near the house, built a new one on the Oxford road, about a mile from the mansion house. But the poor people were very unwilling to leave their old habitation and several houses in the New Village remained for a long time uninhabited. And this was Goldsmith’s Deserted Village — so Lord Harcourt told me.

Habitat Preference, Reproduction and Diet of the Earthworm Eel, Chendol keelini (Teleostei: Chaudhuriidae)

The ecology of the earthworm eel, Chendol keelini, was studied in the field over a period of nine months. In addition this information was supplemented by aquarium observations. The species was most abundant in pools where it was associated with leaf litter and mats of fine tree roots along the banks. It fed on benthic invertebrates, especially chironomid and ephemeropteran larvae. C. keelini is sexually dimorphic; adult males develop a headhump and grow to a larger size than females. Reproduction was seasonal; the reproductive phase coincided with the wet season and lasted for several months. Fecundity was around 40 eggs per clutch. The eggs were spherical, between 1.2 and 1.5 mm in diameter, and possessed a pair of long filaments for adhesion to the substrate. Females probably spawned more than once during the breeding season. The length frequency distributions and juvenile growth suggest that C. keelini is a short-lived species that matures during the first year with few individuals surviving to the second breeding season.

Defining competition vectors in a temperate alley cropping system in the midwestern USA; 4. The economic return of ecological knowledge.

We tested the economic value of ecological knowledge in a midwestern USA alley-cropping system where row crops are planted in alleys between fine hardwood trees grown for veneer. Economic models were constructed to compare among agroforestry designs as well as to compare agroforestry with traditional forest plantation culture and row crop monoculture and rotational management. The general modeling approach was to quantify production inputs and outputs, estimate costs and revenues, simulate tree growth and crop productivity in agroforestry configurations, and estimate discounted cash flows. We incorporated scenarios that controlled both above- and below-ground competition through appropriate management as found in our previous research. This research showed the importance of below-ground competition in determining crop yields and the period of time that crop income could be expected from the agroforestry interplanting. Net present values and internal rates of return showed that agroforestry systems were generally more favorable investments than traditional agriculture and forestry. More importantly, the use of simple management techniques targeted at reducing below-ground competition allowed longer cultivation of row crops, greatly increasing returns to the landowner. Thus, the economic benefit of understanding the ecological interactions within agroforestry plantings dictates that accurate assessment of agroforestry alternatives will require the modeling of agroforestry as an integrated, interactive system.

Fine root biomass and tree species effects on potential N mineralization in afforested sodic soils.

The study was carried out under three types of plantation forest of 40 years, growing on infertile sodic soils, poor in organic matter and N content, of Indogangetic alluvium at Lucknow (26°45′ N; 80°53′ E). Fine root biomass estimated under three forests did not differ much with season, or with species (106–113 g m-2) but varied with soil depth to 0.45 m. The proportion of very fine roots (<0.5 mm) increased with soil depth. Available N in soil was greatest under mixed forest followed by Eucalyptus camaldulensis and Acacia nilotica planted soils. N was maximum in summer season and decreased with soil depth. Nitrogen mineralization during anerobic incubation of 14 days could not be differentiated by tree species, but the monsoon season favoured the process and winter season retarded it. Mineralization decreased with soil depth corresponding to fine roots. There was a reduction in bulk density of soil, pH and EC in forested soil compared to a similar but non forested soil, whereas, organic C and total N increased in forested soils. N mineralization was found to be affected significantly with the fine root biomass and available N content in the soils, whereas negative relations of mineralized N with pH and EC were noticed, though these were not significantly different in this study.

Effect of liming on fine root cation exchange sites of oak

Nutrient acquisition has been shown to be related to the root cation exchange capacity of roots (root‐CEC). Here, the effects of root‐age and liming or gypsum treatments on root‐CEC of fine roots of sessile oak [Quercus petraea. (M.) Liebl.] were studied. In the field, sampling was carried out one to five years, and in rootboxes 3.5 months, after the treatments. Root‐CEC was determined by an adapted desorption method based on percolation with 10−2 NCuSO4. The results showed that the root‐CEC was higher in young whitish roots than in older brownish roots, mainly as a result of higher concentrations of potassium (K). Liming or gypsum applications increased relative occupation by calcium (Ca) of root‐CEC and Ca/aluminum (Al) molar ratio, while decreasing relative occupation of Al (all significant at P<0.05), and this was true for older brownish roots and in the field, but not for young whitish roots. This indicates that the potential of fine roots for uptake of base cations, decreasing with root age in the control, could be maintained or increased after liming or gypsum treatments. Both treatments acted against ‘age’, so that for a given root‐age the roots of the liming or gypsum treatment were in fact ‘chemically’ younger than those of the control. The results support other results on fine root turnover, fine root mortality, tree growth, and foliar nutrition, and suggest that liming and gypsum enhanced root function, perhaps by extending the effective uptake lifetime.

Tree Vectorization: A Methodology to Characterize Fine Tree Architecture in Support of Remote Sensing Models

RÉSUMÉLa structure du couvert végétal est cruciale pour l'interprétation d'images en télédétection optique et micro-onde des forêts. L'utilisation de modèles par la communauté scientifique pour une meilleure compréhension de l'interaction entre le rayonnement incident (signal) et les composantes de la forêt est à la hausse. En soutien à ces efforts de modélisation, une méthode visant à décrire l'architecture détaillée des arbres fut développée. Cette méthode permet la reconstruction statistique en trois dimensions d'un arbre à partir d'un échantillonnage sélectif de ses composantes structurales. Ainsi, une stratégie d'échantillonnage est proposée afin de recueillir l'information (descriptive et spatiale) sur les branches et leurs segments de bois. Une base de données complète de vectorisation implique l'information sur les aspects généraux de l'arbre, la topologie, et un ensemble d'attributs et de mesures sur le feuillage. Une procédure de reconstruction tridimensionnelle intègre les paramètres des données de vectorisation pour une représentation complète des branches et de l'arbre. L'intégrité de la variation spatiale est assurée par la cueillette de données au niveau des segments de bois. La méthode de vectorisation n'assume aucune connaissance au préalable de l'arrangement des branches. De plus elle fournie des estimés localisés de la biomasse de bois et de feuillage. L'information sur les segments de bois par classe de diamètre peut être décidé après la reconstruction. Les résultats obtenus pour des pins gris sont présentés.

Modelling light obstruction in three conifer forests using hemispherical photography and fine tree architecture

A catalogue of hemispherical photographs was collected from conifer forest plantations in order to assess light obstruction by tree crowns. The three conifer species of interest were red pine ( Pinus resinosa), jack pine ( Pinus banksiana Lamb.), and white spruce ( Picea glauca). A tree reconstruction technique called the vectorization method provided the means by which to reproduce fine 3-dimensional spatial distributions of the foliage and support structures of forest trees. More specifically, the detailed geometry of three selected canopies was simulated using the data set produced from the vectorization method and the in situ site characterisation. Moreover, a ray tracing model based on material density provided by the vectorization was developed to replicate hemispherical photos taken looking up from beneath the canopy. The comparison of in situ with simulated hemispherical photographs met three objectives: 1. 1. to estimate the elementary scale driving the obstruction patterns, 2. 2. to validate the vectorization method, and 3. 3. to assess the degree to which the trunks and support structures obstruct light.

15N abundance of surface soils, roots and mycorrhizas in profiles of European forest soils.

15N natural abundances of soil total N, roots and mycorrhizas were studied in surface soil profiles in coniferous and broadleaved forests along a transect from central to northern Europe. Under conditions of N limitation in Sweden, there was an increase in δ15N of soil total N of up to 9% from the uppermost horizon of the organic mor layer down to the upper 0-5 cm of the mineral soil. The δ15N of roots was only slightly lower than that of soil total N in the upper organic horizon, but further down roots were up to 5% depleted under such conditions. In experimentally N-enriched forest in Sweden, i.e. in plots which have received an average of c. 100 kg N ha-1 year-1 for 20 years and which retain less than 50% of this added N in the stand and the soil down to 20 cm depth, and in some forests in central Europe, the increase in δ15N with depth in soil total N was smaller. An increase in δ15N of the surface soil was even observed on experimentally N-enriched plots, although other data suggest that the N fertilizer added was depleted in15N. In such cases roots could be enriched in15N relative to soil total N, suggesting that labelling of the surface soil is via the pathway: - available pools of N-plant N-litter N. Under N-limiting conditions roots of different species sampled from the same soil horizon showed similar δ15N. By contrast, in experimentally N-enriched forest δ15N of roots increased in the sequence: ericaceous dwarf shrubs<Scots pine<grass, suggesting increasing use of inorganic N along the sequence. Complementary studies at the major transect sites had shown that 90-99% of fine tree roots had ectomycorrhizas (ECMs). ECMs were 2% more enriched than corresponding non-mycorrhizal fine roots. Fungal sheaths stripped off ECMs were 2.4-6.4 enriched relative to the remaining root core. It is suggested that a flux of N through ECMs to aboveground parts in N-limited forests would leave 15N enriched compounds in fungal material, which could contribute to explain the observed δ15N profiles if fungal material is enriched, because it is a precursor of stable organic matter and recalcitrant N. This could act in addition to the previous explanation of the isotopically lighter soil surface in forests: plant uptake of 15N-depleted N and its redeposition onto the soil surface by litter-fall.

Nutrient losses after clearfelling in Beddgelert Forest: a comparison of the effects of conventional and whole-tree harvest on soil water chemistry

The effects of conventional, bole only harvesting (CH) and whole-tree harvesting (WTH) on major inorganic nutrient concentrations (K, NO3-N, NH4-N, PO4-P and Ca) in soil water are described from Beddgelert forest in North Wales. Monitoring of nutrient leaching losses, and the timing thereof, from brash through the soil and into streams draining the CH areas allowed assessments to be made of the value of brash as a nutrient source for second rotation crops. Most of the K (around 100 kg ha-1) and one-third of the P (10 out of 30 kg ha-1) leached out of the brash lying on the CH plots within one year of felling. A pulse of K passed through the soil profile, but less than half this K reached the streams. In contrast, the P was immobilized in the soil. The lack of brash resulted in the absence of K and P pulses on the WTH plots. On the CH plots, brash was a net sink for inorganic-N for 3 years after felling. However, in both CH and WTH, a pulse of nitrate was observed in the soil and also in streams draining CH areas. The source of this nitrate may have been death of fine tree roots, followed by rapid mineralization and nitrification. Calculation of a nutrient budget for a complete crop rotation indicates that P and Ca losses in harvested material are likely to result in long-term depletion of these elements, and that the effects will be significantly more severe if WTH is practised.